Goodrive350 Series High-performance Multi-function Inver ter. Operation manual

Chapter 7

Fault

Fault type

Possible cause

Corrective measures

code

There is no data

Check whether the

DeviceNET card

transmission between the

communication card wiring is

E-DEV

communication

communication card and the

loose or dropped

timeout fault

host computer (or PLC)

Can master/slave

There is no data

Check whether the

communication card

transmission between the

communication card wiring is

ESCAN

communication

CAN master and slave

loose or dropped

timeout fault

communication cards

Master-slave

Detect the CAN slave inverter

Fault occurred to one of the

S-Err

synchronous CAN

and analyze the corresponding

CAN slave inverters

slave fault

fault cause of the inverter

7.5.2 Other state

Displayed code

State type

Possible cause

Solution

System power

The system is powered off or

Check the grid

PoFF

failure

the bus voltage is too low.

conditions.

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Chapter 7

7.6 Analysis on common faults

7.6.1 Motor fails to work

Motor fails to work

Whether the POWER

indicator is on?

Whether the air switch

Close the air

Whether the keypad

and EM contactor on the

contactor

displays information?

input side are closed?

Yes

Running

Rectify the fault

Yes

Whether fault information

Check the voltage

Normal

properly

based on the

is displayed?

of RST with a

Inverter fault

fault inforamtion

multimeter

Normal

Communication

Exception occurs

Whether it runs

Terminal

properly after the

Whether communication

Identify the channel of

Check the voltage

Running

parameters are

parameters are properly set?

running commands

of the grid

properly

reset?

Exception occurs

Yes

Keypad

Normal

normal

Normal

Whether it runs

Whether the

Running

Press RUN to run

Check whether the input terminal

properly after the

Running

communication wiring

properly

is in the correct state

terminal is closed?

properly

is performed properly?

Yes

Exception occurs

Whether the speed

Normal

Whether it runs properly after the

Normal

command is set

speed command is properly set?

running

properly?

Yes

Exception occurs

Check the voltage of

Inverter fault

UVW with a multimeter

Normal

Whether the motor is

Wire the motor

properly wired?

properly

Yes

Whether the load is too

Yes

Reduce the load if

Motor fault

the motor is locked

heavy?

due to heavy loads

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Chapter 7

7.6.2 Motor vibrates

Motor vibrates or emits

an unusual sound

Whether the motor

Set the motor type

parameters and motor type

and parameters

are set correctly ?

correctly

Yes

Whether autotuning is

Perform autotuning

performed?

Yes

Whether the V/F

Whether it is vector

vibration parameter is

control?

set properly?

Yes

Whether the ASR and ACR

Set the parameters

Set the parameter

parameters are set

properly

properly?

Yes

Whether unusual

Yes

Check the set

fluctuations occurs when it

frequency

runs at the set frequency?

Whether unusual

Yes

fluctuations occurs on the

Check the load

load?

If it is an inverter fault,

contact our company

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Chapter 7

7.6.3 Overvoltage

Overvoltage fault

Whether the voltage of the power

Ensure the power supply

supply is within the standard range?

meets the requirement

Yes

Whether UVW on the output

side ofn the inverter is short to

Yes

Rectify the short-circuit

ground?

fault and perform the

Whether the wiring on the

wiring properly

output side of the inverter is

performed

properly?

Yes

Whether the ACC/DEC

Whether the ACC/DEC time

Prolong the ACC/DEC

time is too short?

can be prolonged?

time

Yes

Whether to use a

Yes

Check the load and adjust

Whether the loaded motor

Add brake accessories

is drived reversely?

brake accessory?

Adjust the brake

If it is an inverter fault,

accessories and

contact our company

resistance

7.6.4 Undervoltage

Undervoltage fault

Whether the voltage of the

Yes

Ensure the power supply

power supply is within the

meet the requirement

standard range?

Whether the air switch and

Yes

Close the air switch and

contactor are opened or

contactor; and rectify the

encounter exceptions?

exceptions

Whether a large-power device

Yes

Adjust the input of the

is running on the grid that pulls

grid

down the voltage of the grid?

Whether the inverter is

Yes

Identify the power-off

powered off during

causes, and rectify the

running?

exceptions

If it is an inverter fault,

contact our company

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Chapter 7

7.6.5 Unusual heating of motor

Unusual heating of the

motor

Whether the motor

Set the motor

parameters are set

parameters

correctly?

correctly

Yes

Whether parameter

Parameter

autotuning is

autotune

performed?

Yes

Whether the inverter runs

at a low speed all the time?

Yes

Whether it is a variable-

Use a variable-

frequency motor?

frequency motor

Yes

Whether the load is

Yes

Reduce the

too heavy?

load

Whether the three

Replace the

phases of the motor are

motor

balanced?

Yes

Set the carrier

Whether the carrier

frequency

frequency is too low?

properly

Whether the motor

Yes

Add an output

cable is too long?

filter

If it is an inverter fault,

contact our company

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Chapter 7

7.6.6 Inverter overheating

Inverter overheating

Whether the load is too

Yes

Reduce the load and

heavy or the capacity of

increase the capacity

the inverter is too small?

of the inverter

Whether the ambient

Yes

Add a cooling device

temperature is too

or derate the inverter

high?

Whether the fan of

Yes

If it is an inverter fault,

the inverter emits an

contact our company

unusual sound?

Yes

Clean the heat sink to

Whether the heat sink

improve the cooling

is blocked?

conditions

Whether the carrier

Yes

Reduce the carrier

frequency is too high?

frequency

If it is an inverter fault,

contact our company

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Chapter 7

7.6.7 Motor stalls during ACC

Motor stalls during

ACC

Yes

Whether the ACC

Increase the ACC

time is too short?

time

Check the voltage of the

Yes

Use larger cables, shorten the

terminals of the motor with a

wiring distance, adjust the voltage

multimeter. Whether the voltage

drop of the output reactor, etc.

is within the defined range?

Whether the load

Yes

Whether a special

Contact our

or inertia is too

motor is used?

company

large?

Reduce the torque of

Reduce the inertia of

Yes

the load

and

Whether the load

the load and

increase the capacity

torque is too large?

increase the capacity

of the inverter

If it is an inverter fault

Whether the

Yes

Whether it is V/F

or interference,

torque boost

control?

contact our company

is too high?

Yes

Whether parameter

Modify the torque

autotuning is

Overcurrent

boost

performed?

Yes

If it is an inverter fault or

interference, contact our

company

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Chapter 7

7.6.8 Overcurrent

Overcurrent

Whether UVW on the

output side of the inverter

Rectify the short-to-

is short to ground?

Yes

ground fault, and

Remove the motor cable

configure the motor

and checked whether it is

cables properly

connected to earth.

Whether the motor is

Yes

Replace the motor

short to ground?

Whether the motor type and

Set the motor type and

parameters are set correctly?

parameters correctly

Yes

Whether parameter

Perform parameter

autotuning is

autotuning

performed?

Yes

Whether the

Yes

Adjust the ACC/DEC

ACC/DEC time is too

time

short?

Whether the load is

Yes

Reduce the load and

increase the capacity of

too heavy?

the inverter

Whether there are

Yes

Remove the

interference sources?

interference sources

Decrease the torque

Yes

Whether the torque

Yes

Whether it is V/F

boost

boost is too high?

control?

Whether the multi-

Whether the ASR and ACR

Set the ASR and ACR

Adjust the V/F curve

dots V/F curve is set

parameters are set properly?

parameters properly

properly?

Yes

Set the

Yes

Whether unusual

If it is an inverter fault,

V/F vibration control

vibration occurs on

contact our company

parameters properly

the motor?

If it is an inverter fault,

contact our company

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Chapter 7

7.7 Countermeasures on common interference

7.7.1 Interference on meter switches and sensors

Interference phenomenon

Pressure, temperature, displacement, and other signals of a sensor are collected and displayed by a

human-machine interaction device. The values are incorrectly displayed as follows after the inverter

is started:

1. The upper or lower limit is wrongly displayed, for example, 999 or -999.

2. The display of values jumps (usually occurring on pressure transmitters).

3. The display of values is stable, but there is a large deviation, for example, the temperature is

dozens of degrees higher than the common temperature (usually occurring on thermocouples).

4. A signal collected by a sensor is not displayed but functions as a drive system running feedback

signal. For example, an inverter is expected to decelerate when the upper pressure limit of the

compressor is reached, but in actual running, it starts to decelerate before the upper pressure

limit is reached.

5. After an inverter is started, the display of all kinds of meters (such as frequency meter and current

meter) that are connected to the analog output (AO) terminal of the inverter is severely affected,

displaying the values incorrectly.

6. Proximity switches are used in the system. After an inverter is started, the indicator of a proximity

switch flickers, and the output level flips.

Solution

1. Check and ensure that the feedback cable of the sensor is 20 cm or farther away from the motor

cable.

2. Check and ensure that the ground wire of the motor is connected to the PE terminal of the

inverter (if the ground wire of the motor has been connected to the ground block, you need to use

a multimeter to measure and ensure that the resistance between the ground block and PE

terminal is lower than 1.5 Ω).

3. Try to add a safety capacitor of 0.1 μF to the signal end of the feedback signal terminal of the

sensor.

4. Try to add a safety capacitor of 0.1 μF to the power end of the sensor meter (pay attention to the

voltage of the power supply and the voltage endurance of the capacitor).

5. For interference on meters connected to the AO terminal of an inverter, if AO uses current signals

of 0 to 20 mA, add a capacitor of 0.47 μF between the AO and GND terminals; and if AO uses

voltage signals of 0 to 10 V, add a capacitor of 0.1 μF between the AO and GND terminals.

Note:

1. When a decoupling capacitor is required, add it to the terminal of the device connected to the

sensor. For example, if a thermocouple is to transmit signals of 0 to 20 mA to a temperature meter,

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Chapter 7

the capacitor needs to be added on the terminal of the temperature meter.; if an electronic ruler is

to transmit signals of 0 to 30 V to a PLC signal terminal, the capacitor needs to be added on the

terminal of the PLC.

2. If a large number of meters or sensors are disturbed. It is recommended that you configure an

external C2 filter on the input power end of the inverter. For models of filters, see section D.7.

7.7.2 Interference on communication

Interference phenomenon

The interference described in this section on 485 communication mainly includes communication

delay, out of sync, occasional power-off, or complete power-off that occurs after an inverter is started.

If the communication cannot be implemented properly, regardless of whether the inverter is running,

the exception is not necessarily caused by interference. You can find out the causes as follows:

1. Check whether the 485 communication bus is disconnected or in poor contact.

2. Check whether the two ends of line A or B are connected reversely.

3. Check whether the communication protocol (such as the baud rate, data bits, and check bit) of

the inverter is consistent with that of the upper computer.

If you are sure that communication exceptions are caused by interference, you can resolve the

problem through the following measures:

1. Simple inspection.

2. Arrange the communication cables and motor cables in different cable trays.

3. In multi-inverter application scenarios, adopt the chrysanthemum connection mode to connect

the communication cables between inverters, which can improve the anti-interference capability.

4. In multi-inverter application scenarios, check and ensure that the driving capacity of the master is

sufficient.

5. In the connection of multiple inverters, you need to configure one 120 Ω terminal resistor on each

end.

Solution

1. Check and ensure that the ground wire of the motor is connected to the PE terminal of the

inverter (if the ground wire of the motor has been connected to the ground block, you need to use

a multimeter to measure and ensure that the resistance between the ground block and PE

terminal is lower than 1.5 Ω).

2. Do not connect the inverter and motor to the same ground terminal as the upper computer. It is

recommended that you connect the inverter and motor to the power ground, and connect the

upper computer separately to a ground stud.

3. Try to short the signal reference ground terminal (GND) of the inverter with that of the upper

computer controller to ensure that ground potential of the communication chip on the control

board of the inverter is consistent with that of the communication chip of the upper computer.

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Chapter 7

4. Try to short GND of the inverter to its ground terminal (PE).

5. Try to add a safety capacitor of 0.1 μF on the power terminal of the upper computer (PLC, HMI,

and touch screen). During this process, pay attention to the voltage of the power supply and the

voltage endurance capability of the capacitor. Alternatively, you can use a magnet ring (Fe-based

nanocrystalline magnet rings are recommended). Put the power L/N line or +/- line of the upper

computer through the magnet ring in the same direction and wind 8 coils around the magnet ring.

7.7.3 Failure to stop and indicator shimmering due to motor cable coupling

Interference phenomenon

1. Failure to stop

In an inverter system where an S terminal is used to control the start and stop, the motor cable and

control cable are arranged in the same cable tray. After the system is started properly, the S terminal

cannot be used to stop the inverter.

2. Indicator shimmering

After an inverter is started, the relay indicator, power distribution box indicator, PLC indicator, and

indication buzzer shimmers, blinks, or emits unusual sounds unexpectedly.

Solution

1. Check and ensure that the exception signal cable is arranged 20 cm or farther away from the

motor cable.

2. Add a safety capacitor of 0.1 μF between the digital input terminal (S) and the COM terminal.

3. Connect the digital input terminal (S) that controls the start and stop to other idle digital input

terminals in parallel. For example, if S1 is used to control the start and stop and S4 is idle, you

can try to connect connect S1 to S4 in parallel.

Note: If the controller (such as PLC) in the system controls more than 5 inverters at the same

time through digital input terminals (S), this scheme is not available.

7.7.4 Leakage current and interference on RCD

Inverters output high-frequency PWM voltage to drive motors. In this process, the distributed

capacitance between the internal IGBT of an inverter and the heat sink and that between the stator

and rotor of a motor may inevitably cause the inverter to generate high-frequency leakage current to

the ground. A residual current operated protective device

(RCD) is used to detect the

power-frequency leakage current when a grounding fault occurs on a circuit. The application of an

inverter may cause misoperation of a RCD.

1. Rules for selecting RCDs

(1)

Inverter systems are special. In these systems, it is required that the rated residual current of

common RCDs at all levels is larger than 200 mA, and the inverters are grounded reliably.

(2)

For RCDs, the time limit of an action needs to be longer than that of a next action, and the time

difference between two actions need to be longer than 20 ms. For example, 1s, 0.5s, and 0.2s.

(3)

For circuits in inverter systems, electromagnetic RCDs are recommended. Electromagnetic

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Chapter 7

RCDs have strong anti-interference capability, and thus can prevent the impact of

high-frequency leakage current.

Electronic RCD

Electromagnetic RCD

Requiring highly sensitive, accurate, and

stable zero-phase sequence current

Low cost, high sensitivity, small in volume,

transformer, using permalloy

susceptible to voltage fluctuation of the grid

high-permeability materials, complex process,

and ambient temperature, weak

high cost, not susceptible to voltage

anti-interference capability

fluctuation of the power supply and ambient

temperature, strong anti- interference

capability

2. Solution to RCD misoperation (handling the inverter)

Try to remove the jumper cap at "EMC/J10" on the middle casing of the inverter.

Try to reduce the carrier frequency to 1.5 kHz (P00.14=1.5).

Try to modify the modulation mode to "3PH modulation and 2PH modulation" (P8.40=0).

3. Solution to RCD misoperation (handling the system power distribution)

(1)

Check and ensure that the power cable is not soaking in water.

(2)

Check and ensure that the cables are not damaged or spliced.

(3)

Check and ensure that no secondary grounding is performed on the neutral wire.

(4)

Check and ensure that the main power cable terminal is in good contact with the air switch or

contactor (all screws are tightened).

(5)

Check 1PH powered devices, and ensure that no earth lines are used as neutral wires by these

devices.

(6)

Do not use shielded cables as inverter power cables and motor cables.

7.7.5 Live device chassis

Phenomenon

After an inverter is started, there is sensible voltage on the chassis, and you may feel an electric

shock when touching the chassis. The chassis, however, is not live (or the voltage is far lower than

the human safety voltage) when the inverter is powered on but not running.

Solution

1. If there is power distribution grounding or ground stud on the site, ground the cabinet chassis of

the drive system through the power ground or stud.

2. If there is no grounding on the site, you need to connect the motor chassis to the ground terminal

PE of the inverter, and ensure that the jumper at "EMC/J10" on the middle casing of the inverter

is shorted.

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Chapter 8

Chapter 8 Maintenance and hardware fault diagnosis

8.1 What this chapter contains

This chapter describes how to carry out preventive maintenance on Goodrive350 series inverters.

8.2 Periodical inspection

Little maintenance is required when inverters are installed in environments that meet requirements.

The following table describes the routine maintenance periods recommended by INVT.

Subject

Item

Method

Criterion

Check the temperature, and

humidity, and whether there is

Visual inspection,

The requirements

vibration, dust, gas, oil spray,

and use instruments

stated in this

and water droplets in the

for measurement.

manual are met.

Ambient environment

environment.

Check whether there are

There are no tools

foreign matters, such as tools,

or dangerous

Visual inspection

or dangerous substances

substances placed

placed nearby.

nearby.

Use multimeters or

The requirements

Check the voltage of the main

Voltage

other instruments for

stated in this

circuit and control circuit.

measurement.

manual are met.

Check the display of

The characters are

Visual inspection

information.

displayed properly.

Keypad

The requirements

Check whether characters are

Visual inspection

stated in this

not completely displayed.

manual are met.

Check whether the bolts

No exception

Screw them up.

loose or come off.

occurs.

Check whether the machine

is deformed, cracked, or

No exception

damaged, or their color

Visual inspection

occurs.

changes due to overheating

and aging.

Main

Common

No exception

circuit

occurs.

Note:

Check whether there are

Discoloration of

Visual inspection

stains and dust attached.

copper bars does

not mean that they

cannot work

properly.

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Chapter 8

Subject

Item

Method

Criterion

Check whether the

conductors are deformed or

No exception

Visual inspection

their color change due to

occurs.

Conductor and

overheat.

wire

Check whether the wire

No exception

sheaths are cracked or their

Visual inspection

occurs.

color changes.

Check whether there is

No exception

Terminal block

Visual inspection

damage.

occurs.

Check whether there is

electrolyte leakage,

No exception

Visual inspection

discoloration, cracks, and

occurs.

chassis expansion.

Determine the

service life based on

the maintenance

Filter capacitor

Check whether the safety

No exception

information, or

valves are released.

occurs.

measure them

through electrostatic

capacity.

Check whether the

Use instruments to

Electrostatic

electrostatic capacity is

measure the

capacity ≥ initial

measured as required.

capacity.

value × 0.85

Check whether there is

Olfactory and visual

No exception

displacement caused due to

inspection

occurs.

overheat.

Visual inspection, or

Resistor

remove one end of

Resistance range:

Check whether the resistors

the connection cable

±10% (of the

are disconnected.

and use a

standard

multimeter for

resistance)

measurement.

Check whether there is

Auditory, olfactory,

Transformer

No exception

unusual vibration sounds or

and visual

and reactor

occurs.

smells.

inspection

Check whether there are

Electromagnetic

No exception

vibration sounds in the

Auditory inspection

contactor and

occurs.

workshop.

relay

Check whether the contacts

Visual inspection

No exception

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Chapter 8

Subject

Item

Method

Criterion

are in good contact.

occurs.

Check whether the screws

No exception

Screw them up.

and connectors loose.

occurs.

Check whether there is

Olfactory and visual

No exception

unusual smell or

inspection

occurs.

discoloration.

Check whether there are

Control

Control PCB,

No exception

cracks, damage, deformation,

Visual inspection

circuit

connector

occurs.

or rust.

Visual inspection,

Check whether there is

and determine the

No exception

electrolyte leakage or

service life based on

occurs.

deformation.

the maintenance

information.

Auditory and visual

Check whether there are

inspection, and turn

The rotation is

unusual sounds or vibration.

the fan blades with

smooth.

your hand.

Check whether the bolts

No exception

Screw them up.

Cooling fan

loose.

occurs.

Visual inspection,

Cooling

Check whether there is

and determine the

system

No exception

decoloration caused due to

service life based on

occurs.

overheat.

the maintenance

information.

Check whether there are

foreign matters blocking or

No exception

Ventilation duct

Visual inspection

attached to the cooling fan, air

occurs.

inlets, or air outlets.

For more details about maintenance, contact the local INVT office, or visit our website

http://www.invt.com.cn, and choose Service and Support > Online Service.

8.3 Cooling fan

The service life of the cooling fan of the inverter is more than 25,000 hours. The actual service life of

the cooling fan is related to the use of the inverter and the temperature in the ambient environment.

You can view the running duration of the inverter through P07.14 (Accumulated running time).

The increase of the bearing noise indicates a fan fault. If the inverter is applied in a key position,

replace the fan once the fan starts to generate unusual noise. You can purchase spare parts of fans

from INVT.

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Chapter 8

Cooling fan replacement

 Read the safety precautions carefully and follow the instructions to perform

operations. Otherwise, physical injuries or damage to the device may be

caused.

1. Stop the device, disconnect the AC power supply, and wait for a time no shorter than the waiting

time designated on the inverter.

2. Open the cable clamp to loose the fan cable (for inverters of 380 V, 1.5 to 30 kW, the middle

casing needs to be removed).

3. Remove the fan cable.

4. Remove the fan with a screwdriver.

5. Install a new fan in the inverter in the reverse steps. Assemble the inverter. Ensure that the air

direction of the fan is consistent with that of the inverter, as shown in the following figure.

Rotating direction

Air direction

Air

direction

Fig 8.1 Fan maintenance for inverters of 7.5 kW or higher

6. Power on the inverter.

8.4 Capacitor

8.4.1 Capacitor reforming

If the inverter has been left unused for a long time, you need to follow the instructions to reform the

DC bus capacitor before using it. The storage time is calculated from the date the inverter is

delivered.

Storage time

Operation principle

Less than 1 year

No charging operation is required.

The inverter needs to be powered on for 1 hour before the first running

1 to 2 years

command.

2 to 3 years

Use a voltage controlled power supply to charge the inverter:

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Chapter 8

Storage time

Operation principle

Charge the inverter at 25% of the rated voltage for 30 minutes, and

then charge it at 50% of the rated voltage for 30 minutes, at 75% for

another 30 minutes, and finally charge it at 100% of the rated voltage

for 30 minutes.

Use a voltage controlled power supply to charge the inverter:

Charge the inverter at 25% of the rated voltage for 2 hours, and then

More than 3 years

charge it at 50% of the rated voltage for 2 hours, at 75% for another 2

hours, and finally charge it at 100% of the rated voltage for 2 hours.

The method for using a voltage controlled power supply to charge the inverter is described as follows:

The selection of a voltage controlled power supply depends on the power supply of the inverter. For

inverters with an incoming voltage of 1PH/3PH 230 V AC, you can use a 230 V AC/2 A voltage

regulator. Both 1PH and 3PH inverters can be charged with a 1PH voltage controlled power supply

(connect L+ to R, and N to S or T). All the DC bus capacitors share one rectifier, and therefore they

are all charged.

For inverters of a high voltage class, ensure that the voltage requirement (for example, 380 V) is met

during charging. Capacitor changing requires little current, and therefore you can use a

small-capacity power supply (2 A is sufficient).

The method for using a resistor (incandescent lamp) to charge the drive is described as follows:

If you directly connect the drive device to a power supply to charge the DC bus capacitor, it needs to

be charged for a minimum of 60 minutes. The charging operation must be performed at a normal

indoor temperature without load, and you must connect a resistor in series mode in the 3PH circuit of

the power supply.

For a 380 V drive device, use a resistor of 1 kΩ/100W. If the voltage of the power supply is no higher

than 380 V, you can also use an incandescent lamp of 100W. If an incandescent lamp is used, it may

go off or the light may become very weak.

Resistor 1 KΩ/100 W

Power supply

Resistor 1 KΩ/100 W

Inverter

380 V

Resistor 1 KΩ/100 W

Fig 8.2 Charging circuit example of driving devices of 380 V

8.4.2 Electrolytic capacitor replacement

 Read the safety precautions carefully and follow the instructions to perform

operations. Otherwise, physical injuries or damage to the device may be

caused.

The electrolytic capacitor of an inverter must be replaced if it has been used for more than 35,000

hours. For details about the replacement, contact the local INVT office.

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Chapter 9

Chapter 9 Communication protocol

9.1 What this chapter contains

This chapter describes the communication protocol of Goodrive350 series products.

Goodrive350 series inverters provide RS485 communication interfaces and adopt the master-slave

communication based on the international standard Modbus communication protocol. You can

implement centralized control (setting commands for controlling the inverter, modifying the running

frequency and related function code parameters, and monitoring the working state and fault

information of the inverter) through PC/PLC, upper control computer, or other devices to meet specific

application requirements.

9.2 Modbus protocol introduction

Modbus is a software protocol, a common language used in electronic controllers. By using this

protocol, a controller can communicate with other devices through transmission lines. It is a general

industrial standard. With this standard, control devices produced by different manufacturers can be

connected to form an industrial network and be monitored in a centralized way.

The Modbus protocol provides two transmission modes, namely American Standard Code for

Information Interchange (ASCII) and remote terminal units (RTU). On one Modbus network, all the

device transmission modes, baud rates, data bits, check bits, end bits, and other basic parameters

must be set consistently.

A Modbus network is a control network with one master and multiple slaves, that is, on one Modbus

network, there is only one device serving as the master, and other devices are the slaves. The master

can communicate with one slave or broadcast messages to all the slaves. For separate access

commands, a slave needs to return a response. For broadcasted information, slaves do not need to

return responses.

9.3 Application of Modbus

Goodrive350 series inverters use the RTU mode provided by the Modbus protocol, and RS485

interfaces are used.

9.3.1 RS485

RS485 interfaces work in half-duplex mode and transmit data signals in the differential transmission

way, which is also referred to as balanced transmission. An RS485 interface uses a twisted pair,

where one wire is defined as A (+), and the other B (-). Generally, if the positive electrical level

between the transmission drives A and B ranges from +2 V to +6 V, the logic is "1"; and if it ranges

from -2 V to -6 V, the logic is "0".

The 485+ terminal on the terminal block of the inverter corresponds to A, and 485- corresponds to B.

The communication baud rate (P14.01) indicates the number of bits transmitted in a second, and the

unit is bit/s

(bps). A higher baud rate indicates faster transmission and poorer anti-interference

capability. When a twisted pair of 0.56 mm (24 AWG) is used, the maximum transmission distance

varies according to the baud rate, as described in the following table.

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Chapter 9

Max. transmission

Baud rate (bps)

distance

2400

1800 m

9600

800 m

4800

1200 m

19200

600 m

When RS485 interfaces are used for long-distance communication, it is recommended that you use

shielded cables, and use the shield layer as the ground wires.

When there are fewer devices and the transmission distance is short, the whole network works well

without terminal load resistors. The performance, however, degrades as the distance increases.

Therefore, it is recommended that you use a 120 Ω terminal resistor when the transmission distance

is long.

9.3.1.1 Application to one inverter

Fig 9.1 is the Modbus wiring diagram of one inverter and a PC. Generally, PCs do not provide RS485

interfaces, so you need to convert an RS232 interface or USB port of a PC to an RS485 interface.

Connect end A of the RS485 interface to the 485+ port on the terminal block of the inverter, and

connect end B to the 485- port. It is recommended that you use shielded twisted pairs. When an

RS232-RS485 converter is used, the cable used to connect the RS232 interface of the PC and the

converter cannot be longer than 15 m. Use a short cable when possible. It is recommended that you

insert the converter directly into the PC. Similarly, when a USB-RS485 converter is used, use a short

cable when possible.

Shielded twisted pair

Ground

RS485 line

Ground

485+

485-

RS232-RS485 converter

Inverter

Fig 9.1 Wiring of RS485 applied to one inverter

9.3.1.2 Application to multiple inverters

In practical application to multiple inverters, chrysanthemum connection and star connection are

commonly used.

According to the requirements of the RS485 industrial bus standards, all the devices need to be

connected in chrysanthemum mode with one 120 Ω terminal resistor on each end, as shown in Fig

9.2. Fig 9.3 is the simplified wiring diagram, and Fig 9.4 is the practical application diagram.

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Chapter 9

120Ω

32 #

Fig 9.2 On-site chrysanthemum connection diagram

A+

B-

A+

B-

Master

31#

Fig 9.3 Simplified chrysanthemum connection diagram

Shielded twisted pair

485 +

485+

485 +

120Ω

Terminal resistor

485-

485 -

485-

Earth

RS232-RS485

Converter

INVT

Max. length of the

GND

inverter

cable: 15 m

Address 1

Address 2

Address N

Fig 9.4 Practical application diagram of chrysanthemum connection

Fig 9.5 shows the start connection diagram. When this connection mode is adopted, the two devices

that are farthest away from each other on the line must be connected with a terminal resistor (in Fig

9.5, the two devices are devices 1# and 15#).

32#

15#

Fig 9.5 Star connection

Use shielded cable, if possible, in multi-device connection. The baud rates, data bit check settings,

and other basic parameters of all the devices on the RS485 line must be set consistently, and

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addresses cannot be repeated.

9.3.2 RTU mode

9.3.2.1 RTU communication frame structure

When a controller is set to use the RTU communication mode on a Modbus network, every byte (8

bits) in the message includes 2 hexadecimal characters (each includes 4 bits). Compared with the

ASCII mode, the RTU mode can transmit more data with the same baud rate.

Code system

• 1 start bit

• 7 or 8 data bits; the minimum valid bit is transmitted first. Each frame domain of 8 bits includes 2

hexadecimal characters (0-9, A-F).

• 1 odd/even check bit; this bit is not provided if no check is needed.

• 1 end bit (with check performed), 2 bits (without check)

Error detection domain

• Cyclic redundancy check (CRC)

The following table describes the data format.

11-bit character frame (Bits 1 to 8 are data bits)

Check

Start bit

BIT1

BIT2

BIT3

BIT4

BIT5

BIT6

BIT7

BIT8

End bit

bit

10-bit character frame (Bits 1 to 7 are data bits)

Check

Start bit

BIT1

BIT2

BIT3

BIT4

BIT5

BIT6

BIT7

End bit

bit

In a character frame, only the data bits carry information. The start bit, check bit, and end bit are used

to facilitate the transmission of the data bits to the destination device. In practical applications, you

must set the data bits, parity check bits, and end bits consistently.

In RTU mode, the transmission of a new frame always starts from an idle time (the transmission time

of 3.5 bytes). On a network where the transmission rate is calculated based on the baud rate, the

transmission time of 3.5 bytes can be easily obtained. After the idle time ends, the data domains are

transmitted in the following sequence: slave address, operation command code, data, and CRC

check character. Each byte transmitted in each domain includes 2 hexadecimal characters (0-9, A-F).

The network devices always monitor the communication bus. After receiving the first domain (address

information), each network device identifies the byte. After the last byte is transmitted, a similar

transmission interval (the transmission time of 3.5 bytes) is used to indicate that the transmission of

the frame ends. Then, the transmission of a new frame starts.

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RTU data frame format

Modbus packet

Start with an idle time (at

End with an idle time (at

Slave

Function

least the transmission

Data

Check

least the transmission

address

code

time of 3.5 bytes)

The information of a frame must be transmitted in a continuous data flow. If there is an interval greater

than the transmission time of 1.5 bytes before the transmission of the entire frame is complete, the

receiving device deletes the incomplete information, and mistakes the subsequent byte for the

address domain of a new frame. Similarly, if the transmission interval between two frames is shorter

than the transmission time of 3.5 bytes, the receiving device mistakes it for the data of the last frame.

The CRC check value is incorrect due to the disorder of the frames, and thus a communication fault

occurs.

The following table describes the standard structure of an RTU frame.

START (frame header)

T1-T2-T3-T4 (transmission time of 3.5 bytes)

Communication address: 0-247 (decimal system) (0 is the

ADDR (slave address domain)

broadcast address)

03H: read slave parameters

CMD (function domain)

06H: write slave parameters

DATA (N-1)

Data of 2×N bytes, main content of the communication as well

DATA (0)

as the core of data exchanging

(data domain)

CRC CHK (LSBs)

Detection value: CRC (16 bits)

CRC CHK high bit (MSBs)

END (frame tail)

T1-T2-T3-T4 (transmission time of 3.5 bytes)

9.3.2.2 RTU communication frame error check modes

During the transmission of data, errors may occur due to various factors. Without check, the data

receiving device cannot identify data errors and may make a wrong response. The wrong response

may cause severe problems. Therefore, the data must be checked.

The check is implemented as follows: The transmitter calculates the to-be-transmitted data based on

a specific algorithm to obtain a result, adds the result to the rear of the message, and transmits them

together. After receiving the message, the receiver calculates the data based on the same algorithm

to obtain a result, and compares the result with that transmitted by the transmitter. If the results are

the same, the message is correct. Otherwise, the message is considered wrong.

The error check of a frame includes two parts, namely, bit check on individual bytes (that is, odd/even

check using the check bit in the character frame), and whole data check (CRC check).

Bit check on individual bytes (odd/even check)

You can select the bit check mode as required, or you can choose not to perform the check, which will

affect the check bit setting of each byte.

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Definition of even check: Before the data is transmitted, an even check bit is added to indicate

whether the number of "1" in the to-be-transmitted data is odd or even. If it is even, the check bit is set

to "0"; and if it is odd, the check bit is set to "1".

Definition of odd check: Before the data is transmitted, an odd check bit is added to indicate whether

the number of "1" in the to-be-transmitted data is odd or even. If it is odd, the check bit is set to "0";

and if it is even, the check bit is set to "1".

For example, the data bits to be transmitted are "11001110", including five "1". If the even check is

applied, the even check bit is set to "1"; and if the odd check is applied, the odd check bit is set to "0".

During the transmission of the data, the odd/even check bit is calculated and placed in the check bit of

the frame. The receiving device performs the odd/even check after receiving the data. If it finds that

the odd/even parity of the data is inconsistent with the preset information, it determines that a

communication error occurs.

CRC check mode

A frame in the RTU format includes an error detection domain based on the CRC calculation. The

CRC domain checks all the content of the frame. The CRC domain consists of two bytes, including 16

binary bits. It is calculated by the transmitter and added to the frame. The receiver calculates the CRC

of the received frame, and compares the result with the value in the received CRC domain. If the two

CRC values are not equal to each other, errors occur in the transmission.

During CRC, 0xFFFF is stored first, and then a process is invoked to process a minimum of 6

contiguous bytes in the frame based on the content in the current register. CRC is valid only for the

8-bit data in each character. It is invalid for the start, end, and check bits.

During the generation of the CRC values, the "exclusive or" (XOR) operation is performed on the

each 8-bit character and the content in the register. The result is placed in the bits from the least

significant bit (LSB) to the most significant bit (MSB), and 0 is placed in the MSB. Then, LSB is

detected. If LSB is 1, the XOR operation is performed on the current value in the register and the

preset value. If LSB is 0, no operation is performed. This process is repeated 8 times. After the last bit

(8^th bit) is detected and processed, the XOR operation is performed on the next 8-bit byte and the

current content in the register. The final values in the register are the CRC values obtained after

operations are performed on all the bytes in the frame.

The calculation adopts the international standard CRC check rule. You can refer to the related

standard CRC algorithm to compile the CRC calculation program as required.

The following is a simple CRC calculation function for your reference (using the C programming

language):

unsigned int crc_cal_value(unsigned char×data_value,unsigned char data_length)

{

int i;

unsigned int crc_value=0xffff;

while(data_length--)

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Chapter 9

{

crc_value^=×data_value++;

for(i=0;i<8;i++)

{

if(crc_value&0x0001)

crc_value=(crc_value>>1)^0xa001;

else

crc_value=crc_value>>1;

}

return(crc_value);

}

In the ladder logic, CKSM uses the table look-up method to calculate the CRC value according to the

content in the frame. The program of this method is simple, and the calculation is fast, but the ROM

space occupied is large. Use this program with caution in scenarios where there are space

occupation limits on programs.

9.4 RTU command code and communication data

9.4.1 Command code: 03H, reading N words (continuously reading a maximum of 16 words)

The command code 03H is used by the master to read data from the inverter. The quantity of data to

be read depends on the "data quantity" in the command. A maximum of 16 pieces of data can be read.

The addresses of the read parameters must be contiguous. Each piece of data occupies 2 bytes, that

is, one word. The command format is presented using the hexadecimal system (a number followed by

"H" indicates a hexadecimal value). One hexadecimal value occupies one byte.

The 03H command is used to read information including the parameters and operation state of the

inverter.

For example, starting from the data address of 0004H, to read two contiguous pieces of data (that is,

to read content from the data addresses 0004H and 0005H), the structure of the frame is described in

the following table.

RTU master command (transmitted by the master to the inverter)

START

T1-T2-T3-T4 (transmission time of 3.5 bytes)

ADDR (address)

01H

CMD (command code)

03H

Most significant byte (MSB) of

00H

the start address

Least significant byte (LSB) of

04H

the start address

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MSB of data quantity

00H

LSB of data quantity

02H

LSB of CRC

85H

MSB of CRC

CAH

END

T1-T2-T3-T4 (transmission time of 3.5 bytes)

The value in START and END is "T1-T2-T3-T4 (transmission time of 3.5 bytes)", indicating that the

RS485 needs to stay idle for at least the transmission time of 3.5 bytes. An idle time is required to

distinguish on message from another to ensure that the two messages are not regarded as one.

The value of ADDR is 01H, indicating that the command is transmitted to the inverter whose address

is 01H. The ADDR information occupies one byte.

The value of CMD is 03H, indicating that the command is used to read data from the inverter. The

CMD information occupies one byte.

"Start address" indicates that data reading is started from this address. It occupies two bytes, with the

MSB on the left and LSB on the right.

"Data quantity" indicates the quantity of data to be read (unit: word).

The value of "Start address" is 0004H, and that of "Data quantity" is 0002H, indicating that data is to

be read from the data addresses of 0004H and 0005H.

CRC check occupies two bytes, with the LSB on the left, and MSB on the right.

RTU slave response (transmitted by the inverter to the master)

T1-T2-T3-T4 (transmission time of 3.5

START

bytes)

ADDR

01H

CMD

03H

Number of bytes

04H

MSB of data in 0004H

13H

LSB of data in 0004H

88H

MSB of data in 0005H

00H

LSB of data in 0005H

00H

LSB of CRC

7EH

MSB of CRC

9DH

END

T1-T2-T3-T4 (transmission time of 3.5 bytes)

The definition of the response information is described as follows:

The value of ADDR is 01H, indicating that the message is transmitted by the inverter whose address

is 01H. The ADDR information occupies one byte.

The value of CMD is 03H, indicating that the message is a response of the inverter to the 03H

command of the master for reading data. The CMD information occupies one byte.

"Number of bytes" indicates the number of bytes between a byte (not included) and the CRC byte (not

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included). The value 04 indicates that there are four bytes of data between "Number of bytes" and

"LSB of CRC", that is, "MSB of data in 0004H", "LSB of data in 0004H", "MSB of data in 0005H", and

"LSB of data in 0005H".

A piece of data is two bytes, with the MSB on the left and LSB on the right. From the response, we

can see that the data in 0004H is 1388H, and that in 0005H is 0000H.

CRC check occupies two bytes, with the LSB on the left, and MSB on the right.

9.4.2 Command code: 06H, writing a word

This command is used by the master to write data to the inverter. One command can be used to write

only one piece of data. It is used to modify the parameters and operation mode of the inverter.

For example, to write 5000 (1388H) to 0004H of the inverter whose address is 02H, the structure of

the frame is described in the following table.

RTU master command (transmitted by the master to the inverter)

START

T1-T2-T3-T4 (transmission time of 3.5 bytes)

ADDR

02H

CMD

06H

MSB of data writing address

00H

LSB of data writing address

04H

MSB of to-be-written data

13H

LSB of to-be-written data

88H

LSB of CRC

C5H

MSB of CRC

6EH

END

T1-T2-T3-T4 (transmission time of 3.5 bytes)

RTU slave response (transmitted by the inverter to the master)

START

T1-T2-T3-T4 (transmission time of 3.5 bytes)

ADDR

02H

CMD

06H

MSB of data writing address

00H

LSB of data writing address

04H

MSB of to-be-written data

13H

LSB of to-be-written data

88H

LSB of CRC

C5H

MSB of CRC

6EH

END

T1-T2-T3-T4 (transmission time of 3.5 bytes)

Note: The sections 9.2 and 9.3 mainly describes the command formats. For the detailed application,

see the examples in section 9.4.8.

9.4.3 Command code: 08H, diagnosis

Sub-function code description

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Sub-function code

Description

0000

Return data based on query requests

For example, to query about the circuit detection information about the inverter whose address is 01H,

the query and return strings are the same, and the format is described in the following tables.

RTU master command

START

T1-T2-T3-T4 (transmission time of 3.5 bytes)

ADDR

01H

CMD

08H

MSB of the sub-function code

00H

LSB of the sub-function code

00H

MSB of data

12H

LSB of data

ABH

LSB of CRC CHK

ADH

MSB of CRC CHK

14H

END

T1-T2-T3-T4 (transmission time of 3.5 bytes)

RTU slave response

START

T1-T2-T3-T4 (transmission time of 3.5 bytes)

ADDR

01H

CMD

08H

MSB of the sub-function code

00H

LSB of the sub-function code

00H

MSB of data

12H

LSB of data

ABH

LSB of CRC CHK

ADH

MSB of CRC CHK

14H

END

T1-T2-T3-T4 (transmission time of 3.5 bytes)

9.4.4 Command code: 10H, continuous writing

The command code 10H is used by the master to write data to the inverter. The quantity of data to be

written is determined by "Data quantity", and a maximum of 16 pieces of data can be written.

For example, to write 5000 (1388H) and 50 (0032H) respectively to 0004H and 0005H of the inverter

whose slave address is 02H, the structure of the frame is described in the following table.

RTU master command (transmitted by the master to the inverter)

START

T1-T2-T3-T4 (transmission time of 3.5 bytes)

ADDR

02H

CMD

10H

MSB of data writing address

00H

LSB of data writing address

04H

MSB of data quantity

00H

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LSB of data quantity

02H

Number of bytes

04H

MSB of data to be written to 0004H

13H

LSB of data to be written to 0004H

88H

MSB of data to be written to 0005H

00H

LSB of data to be written to 0005H

32H

LSB of CRC

C5H

MSB of CRC

6EH

END

T1-T2-T3-T4 (transmission time of 3.5 bytes)

RTU slave response (transmitted by the inverter to the master)

START

T1-T2-T3-T4 (transmission time of 3.5 bytes)

ADDR

02H

CMD

10H

MSB of data writing address

00H

LSB of data writing address

04H

MSB of data quantity

00H

LSB of data quantity

02H

LSB of CRC

C5H

MSB of CRC

6EH

END

T1-T2-T3-T4 (transmission time of 3.5 bytes)

9.4.5 Data address definition

This section describes the address definition of communication data. The addresses are used for

controlling the running, obtaining the state information, and setting related function parameters of the

inverter.

9.4.5.1 Function code address representation rules

The address of a function code consists of two bytes, with the MSB on the left and LSB on the right.

The MSB ranges from 00 to ffH, and the LSB also ranges from 00 to ffH. The MSB is the hexadecimal

form of the group number before the dot mark, and LSB is that of the number behind the dot mark.

Take P05.06 as an example, the group number is 05, that is, the MSB of the parameter address is the

hexadecimal form of 05; and the number behind the dot mark is 06, that is, the LSB is the

hexadecimal form of 06. Therefore, the function code address is 0506H in the hexadecimal form. For

P10.01, the parameter address is 0A01H.

Function

Setting

Default

Name

Detailed parameter description

Modify

code

range

value

0: Stop after running once

Simple PLC

1: Keep running in the final value

P10.00

0-2

○

mode

after running once

2: Cyclic running

P10.01

Simple PLC

0: No memory after power down

0-1

○

memory

1: Memory after power down

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Chapter 9

Function

Setting

Default

Name

Detailed parameter description

Modify

code

range

value

selection

Note:

1. The parameters in the P99 group are set by the manufacturer. They cannot be read or modified.

Some parameters cannot be modified when the inverter is running; some cannot be modified

regardless of the state of the inverter. Pay attention to the setting range, unit, and related

description of a parameter when modifying it.

2. The service life of the Electrically Erasable Programmable Read-Only Memory (EEPROM) may

be reduced if it is frequently used for storage. For users, some function codes do not need to be

stored during communication. The application requirements can be met by modifying the value of

the on-chip RAM, that is, modifying the MSB of the corresponding function code address from 0

to 1. For example, if P00.07 is not to be stored in the EEPROM, you need only to modify the

value of the RAM, that is, set the address to 8007H. The address can be used only for writing

data to the on-chip RAM, and it is invalid when used for reading data.

9.4.5.2 Description of other function code addresses

In addition to modifying the parameters of the inverter, the master can also control the inverter, such

as start and stop it, and monitor the operation state of the inverter. The following table describes other

function parameters.

Function

Address

Data description

R/W

0001H: Forward running

0002H: Reverse running

0003H: Forward jogging

Communication-based

0004H: Reverse jogging

2000H

R/W

control command

0005H: Stop

0006H: Coast to stop (emergency stop)

0007H: Fault reset

0008H: Jogging to stop

Communication-based frequency setting

(0-

2001H

Fmax, unit: 0.01 Hz)

R/W

PID setting, range (0-1000, 1000 corresponding

2002H

to 100.0%)

PID feedback,

range

(0-1000,

1000

Communication-based

2003H

R/W

corresponding to 100.0%)

value setting

Torque

setting

(-3000-+3000,

1000

2004H

corresponding to 100.0% of the rated current of

R/W

the motor)

Setting of the upper limit of the forward running

2005H

R/W

frequency (0-Fmax, unit: 0.01 Hz)

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Chapter 9

Function

Address

Data description

R/W

Setting of the upper limit of the reverse running

2006H

R/W

frequency (0-Fmax, unit: 0.01 Hz)

Upper limit of the electromotion torque (0-3000,

2007H

1000 corresponding to

100.0% of the rated

R/W

current of the inverter)

Upper limit of the brake torque (0-3000, 1000

2008H

corresponding to 100.0% of the rated current of

R/W

the motor)

Special control command word:

Bit0-1: =00: Motor 1

=01: Motor 2

=10: Motor 3

=11: Motor 4

Bit2:

=1 Torque control disabled

=0: Torque

control cannot be disabled

2009H

R/W

Bit3: =1 Power consumption reset to 0

=0: Power consumption not reset

Bit4:

=1 Pre-excitation

=0: Pre-excitation

disabled

Bit5: =1 DC brake

=0: DC brake disabled

Virtual input terminal command, range: 0x000-

200AH

R/W

0x1FF

Virtual output terminal command, range: 0x00-

200BH

R/W

0x0F

Voltage setting

(used when V/F separation is

implemented)

200CH

R/W

(0-1000, 1000 corresponding to 100.0% of the

rated voltage of the motor)

AO output setting

(-1000-+1000,

1000

200DH

R/W

corresponding to 100.0%)

AO output setting

(-1000-+1000,

1000

200EH

R/W

corresponding to 100.0%)

0001H: Forward running

0002H: Reverse running

0003H: Stopped

Inverter state word 1

2100H

0004H: Faulty

0005H: POFF

0006H: Pre-excited

Bit0:

=0: Not ready to run =1: Ready to run

Inverter state word 2

2101H

Bi1-2: =00: Motor 1

=01: Motor 2

=10: Motor 3

=11: Motor 4

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Function

Address

Data description

R/W

Bit3:

=0: Asynchronous machine

=1:

Synchronous machine

Bit4: =0: No overload alarm =1: Overload alarm

Bit5-Bit6:

=00: Keypad-based control

=01:

Terminal-based control

=10: Communication-based control

Inverter fault code

2102H

See the description of fault types.

Inverter identification

2103H

GD35-----0x0109

code

Running frequency

3000H

0-Fmax (unit: 0.01Hz)

Set frequency

3001H

0-Fmax (unit: 0.01Hz)

Bus voltage

3002H

0.0-2000.0 V (unit: 0.1V)

Output voltage

3003H

0-1200V (unit: 1V)

Output current

3004H

0.0-3000.0A (unit: 0.1A)

Rotating speed

3005H

0-65535 (unit: 1RPM)

Ouptut power

3006H

-300.0-+300.0% (unit: 0.1%)

Output torque

3007H

-250.0-+250.0% (unit: 0.1%)

Closed-loop setting

3008H

-100.0-+100.0% (unit: 0.1%)

Closed-loop feedback

3009H

-100.0-+100.0% (unit: 0.1%)

Input state

300AH

000-1FF

Output state

300BH

000-1FF

Compatible

Analog input 1

300CH

0.00-10.00V (unit: 0.01V)

with CHF100A

Analog input 2

300DH

0.00-10.00V (unit: 0.01V)

and CHV100

Analog input 3

300EH

-10.00-10.00V (unit: 0.01V)

communication

Analog input 4

300FH

addresses

Read input of

3010H

0.00-50.00kHz (unit: 0.01Hz)

high-speed pulse 1

Read input of

3011H

high-speed pulse 2

Read current step of

3012H

0-15

multi-step speed

External length

3013H

0-65535

External count value

3014H

0-65535

Torque setting

3015H

-300.0-+300.0% (unit: 0.1%)

Identification code

3016H

Fault code

5000H

The Read/Write (R/W) characteristics indicate whether a function can be read and written. For

example, "Communication-based control command" can be written, and therefore the command code

6H is used to control the inverter. The R characteristic indicates that a function can only be read, and

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W indicates that a function can only be written.

Note: Some parameters in the preceding table are valid only after they are enabled. Take the running

and stop operations as examples, you need to set "Running command channel" (P00.01) to

"Communication", and set "Communication running command channel" (P00.02) to the Modbus

communication channel. For another example, when modifying "PID setting", you need to set "PID

reference source" (P09.00) to Modbus communication.

The following table describes the encoding rules of device codes (corresponding to the identification

code 2103H of the inverter).

8 MSBs

Meaning

8 LSBs

Meaning

0x08

GD35 vector inverter

0x09

GD35-H1 vector inverter

0x0a

GD300 vector inverter

0xa0

GD350 vector inverter

9.4.6 Fieldbus scale

In practical applications, communication data is represented in the hexadecimal form, but

hexadecimal values cannot represent decimals. For example, 50.12 Hz cannot be represented in the

hexadecimal form. In such cases, we can multiply 50.12 by 100 to obtain an integer 5012, and then

50.12 can be represented as 1394H (5012 in the decimal form) in the hexadecimal form.

In the process of multiplying a non-integer by a multiple to obtain an integer, the multiple is referred to

as a fieldbus scale.

The fieldbus scale depends on the number of decimals in the value specified in "Detailed parameter

description" or "Default value". If there are n decimals in the value, the fieldbus scale m is the

n^th-power of 10. Take the following table as an example, m is 10.

Function

Default

Name

Detailed parameter description

code

value

P01.20

Wake-up-from-sleep delay

0.0-3600.0s (valid when P01.19 is 2)

0.0s

0: Restart is disabled

P01.21

Restart after power cut

1: Restart is enabled

The value specified in "Detailed parameter description" or "Default value" contains one decimal, so

the fieldbus scale is

10. If the value received by the upper computer is

50, the value of

"Wake-up-from-sleep delay" of the inverter is 5.0 (5.0=50/10).

To set the "Wake-up-from-sleep delay" to 5.0s through Modbus communication, you need first to

multiply 5.0 by 10 according to the scale to obtain an integer 50, that is, 32H in the hexadecimal form,

and then transmit the following write command:

01 14

00 32

49 E7

Inverter

Write

Parameter Parameter

CRC

address command address

data

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After receiving the command, the inverter converts 50 into 5.0 based on the fieldbus scale, and then

sets "Wake-up-from-sleep delay" to 5.0s.

For another example, after the upper computer transmits the "Wake-up-from-sleep delay" parameter

read command, the master receives the following response from the inverter:

00 32

39 91

Inverter

Read

2-byte

Parameter

CRC

address command

data

The parameter data is 0032H, that is, 50, so 5.0 is obtained based on the fieldbus scale (50/10=5.0).

In this case, the master identifies that the "Wake-up-from-sleep delay" is 5.0s.

9.4.7 Error message response

Operation errors may occur in communication-based control. For example, some parameters can

only be read, but a write command is transmitted. In this case, the inverter returns an error message

response.

Error message responses are transmitted by the inverter to the master. The following table describes

the codes and definitions of the error message responses.

Code

Name

Definition

The command code received by the upper computer is not allowed

to be executed. The possible causes are as follows:

Invalid

01H

• The function code is applicable only on new devices and is not

command

implemented on this device.

• The slave is in the faulty state when processing this request.

For the inverter, the data address in the request of the upper

Invalid data

computer is not allowed. In particular, the combination of the

02H

address

invalid.

The received data domain contains a value that is not allowed. The

value indicates the error of the remaining structure in the combined

03H

Invalid data bit

request.

Note: It does not mean that the data item submitted for storage in

the register includes a value unexpected by the program.

Operation

The parameter is set to an invalid value in the write operation. For

04H

failure

example, a function input terminal cannot be set repeatedly.

Password

The password entered in the password verification address is

05H

error

different from that set in P03.00.

The length of the data frame transmitted by the upper computer is

Data frame

06H

incorrect, or in the RTU format, the value of the CRC check bit is

error

inconsistent with the CRC value calculated by the lower computer

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Code

Name

Definition

Parameter

The parameter to be modified in the write operation of the upper

07H

read-only

computer is a read-only parameter.

Parameter

cannot be

The parameter to be modified in the write operation of the upper

08H

modified in

computer cannot be modified during the running of the inverter.

running

A user password is set, and the upper computer does not provide

Password

09H

the password to unlock the system when performing a read or write

protection

operation. The error of "system locked" is reported.

When returning a response, the device uses a function code domain and fault address to indicate

whether it is a normal response (no error) or exception response (some errors occur). In a normal

response, the device returns the corresponding function code and data address or sub-function code.

In an exception response, the device returns a code that is equal to a normal code, but the first bit is

logic 1.

For example, if the master device transmits a request message to a slave device for reading a group

of function code address data, the code is generated as follows:

0 0 0 0 0 0 1 1 (03H in the hexadecimal form)

For a normal response, the same code is returned.

For an exception response, the following code is returned:

1 0 0 0 0 0 1 1 (83H in the hexadecimal form)

In addition to the modification of the code, the slave returns a byte of exception code that describes

the cause of the exception. After receiving the exception response, the typical processing of the

master device is to transmit the request message again or modify the command based on the fault

information.

For example, to set the "Running command channel" (P00.01, the parameter address is 0001H) of

the inverter whose address is 01H to 03, the command is as follows:

00 01

00 03

98 0B

Inverter

Write

Parameter

CRC

address command

address

data

But the setting range of the "Running command channel" is 0 to 2. The value 3 exceeds the setting

range. In this case, the inverter returns an error message response as shown in the following:

43 A3

Inverter

Exception

Error code

CRC

address

response code

The exception response code 86H (generated based on the MSB "1" of the write command 06H)

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indicates that it is an exception response to the write command (06H). The error code is 04H. From

the preceding table, we can see that it indicates the error "Operation failure", which means "The

parameter is set to an invalid value in the write operation".

9.4.8 Read/Write operation example

For the formats of the read and write commands, see sections 9.4.1 and 9.4.2.

9.4.8.1 Read command 03H examples

Example 1: Read state word 1 of the inverter whose address is 01H. From the table of other function

parameters, we can see that the parameter address of state word 1 of the inverter is 2100H.

The read command transmitted to the inverter is as follows:

21 00

00 01

8E 36

Inverter

Read

Parameter

Data quantity

CRC

address

command

address

Assume that the following response is returned:

00 03

F8 45

Inverter

Read

Number

CRC

Data content

address

command

of bytes

The data content returned by the inverter is 0003H, which indicates that the inverter is in the stopped

state.

Example 2: View information about the inverter whose address is 03H, including "Type of current

fault" (P07.27) to "Type of last but four fault" (P07.32) of which the parameter addresses are 071BH to

0720H (contiguous 6 parameter addresses starting from 071BH).

The command transmitted to the inverter is as follows:

07 1B

00 06

B5 59

Inverter

Read

Start

6 parameters in total

CRC

address

command address

Assume that the following response is returned:

03 03 0C 00 23 00 23 00 23 00 23 00 23 00 23 5F D2

Inverter

Read Number of

Type of

Type of last

CRC

address command bytes

current fault

last fault

but one fault

but two fault

but three fault

but four fault

From the returned data, we can see that all the fault types are 0023H, that is, 35 in the decimal form,

which means the maladjustment fault (STo)

9.4.8.2 Write command 06H examples

Example 1: Set the inverter whose address is 03H to be forward running. Refer to the table of other

function parameters, the address of "Communication-based control command" is 2000H, and 0001H

indicates forward running, as shown in the following figure.

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Function

Address

Data description

R/W

0001H: Forward running

0002H: Reverse running

0003H: Forward jogging

Communication-based

0004H: Reverse jogging

2000H

R/W

control command

0005H: Stop

0006H: Coast to stop (emergency stop)

0007H: Fault reset

0008H: Jogging to stop

The command transmitted by the master is as follows:

20 00

00 01

42 28

Inverter

Write

Parameter

Forward

CRC

address

command

address

running

If the operation is successful, the following response is returned (same as the command transmitted

by the master):

20 00

00 01

42 28

Inverter

Write

Parameter

Forward

CRC

address

command

address

running

Example 2: Set the "Max. output frequency" of the inverter whose address is 03H to 100 Hz.

Function

Default

Modi

Name

Detailed parameter description

code

value

Used to set the max. output frequency of the

Max. output

inverter. It is the basis of frequency setup and the

P00.03

50.00Hz

◎

frequency

acceleration/deceleration.

Setting range: Max (P00.04, 10.00) -630.00Hz

From the number of decimals, we can see that the fieldbus scale of the "Max. output frequency"

(P00.03) is 100. Multiply 100 Hz by 100. The value 10000 is obtained, and it is 2710H in the

hexadecimal form.

The command transmitted by the master is as follows:

00 03

27 10

62 14

Inverter

Write

Parameter

CRC

address

command

address

data

If the operation is successful, the following response is returned (same as the command transmitted

by the master):

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00 03

27 10

62 14

Inverter

Write

Parameter

CRC

address

command

address

data

Note: In the preceding command description, spaces are added to a command just for explanatory

purposes. In practical applications, no space is required in the commands.

9.4.8.3 Continuously write command 10H examples

Example 1: Set the inverter whose address is 01H to be forward running at the frequency of 10 Hz.

Refer to the table of other function parameters, the address of "Communication-based control

command" is 2000H, 0001H indicates forward running, and the address of "Communication-based

value setting" is 2001H, as shown in the following figure. 10 Hz is 03E8H in the hexadecimal form.

Function

Address

Data description

R/W

0001H: Forward running

0002H: Reverse running

0003H: Forward jogging

Communication-based

0004H: Reverse jogging

2000H

R/W

control command

0005H: Stop

0006H: Coast to stop (emergency stop)

0007H: Fault reset

0008H: Jogging to stop

Communication-based frequency setting

(0-

2001H

Communication-based

Fmax, unit: 0.01 Hz)

R/W

value setting

PID setting, range (0-1000, 1000 corresponding

2002H

to 100.0%)

In the actual operation, set P00.01 to 2 and P00.06 to 8.

The command transmitted by the master is as follows:

20 00

00 02

00 01

03 E8

3B 10

Inverter

Continuous

Parameter

Number of

Froward

10 Hz

CRC

address

write

address

quantity

bytes

running

command

If the operation is successful, the following response is returned:

20 00

00 02

4A 08

Inverter

Continuous

Parameter

CRC

address

write

address

quantity

command

Example 2: Set "Acceleration time" of the inverter whose address is 01H to 10s, and "Deceleration

time" to 20s.

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Function

Default

Modi

Name

Detailed parameter description

code

value

Acceleration

Acceleration time is the time needed for accelerating

Depend

P00.11

○

time 1

from 0Hz to max. output frequency (P00.03).

on model

Deceleration time is the time needed from

decelerating from max. output frequency (P00.03) to

0Hz.

Goodrive350 series inverter defines four groups of

Deceleration

Depend

P00.12

acceleration and deceleration time, which can be

○

time 1

on model

selected via multi-function digital input terminals

(P05 group). The acceleration/deceleration time of

the inverter is the first group by default.

Setting range of P00.11 and P00.12: 0.0-3600.0s

The address of P00.11 is 000B, 10s is 0064H in the hexadecimal form, and 20s is 00C8H in the

hexadecimal form.

The command transmitted by the master is as follows:

00 0B

00 02

00 64

00 C8

F2 55

Inverter

Continuous

Parameter

Number of

10s

20s

CRC

address

write

address

quantity

bytes

command

If the operation is successful, the following response is returned:

00 0B

00 02

30 0A

Inverter

Continuous

Parameter

CRC

address

write

address

quantity

command

Note: In the preceding command description, spaces are added to a command just for explanatory

purposes. In practical applications, no space is required in the commands.

9.4.8.4 Modbus communication commissioning example

A PC is used as the host, an RS232-RS485 converter is used for signal conversion, and the PC serial

port used by the converter is COM1 (an RS232 port). The upper computer commissioning software is

the serial port commissioning assistant Commix, which can be downloaded from the Internet.

Download a version that can automatically execute the CRC check function. The following figure

shows the interface of Commix.

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First, set the serial port to COM1. Then, set the baud rate consistently with P14.01. The data bits,

check bits, and end bits must be set consistently with P14.02. If the RTU mode is selected, you need

to select the hexadecimal form Input HEX. To set the software to automatically execute the CRC

function, you need to select ModbusRTU, select CRC16 (MODBU SRTU), and set the start byte to 1.

After the auto CRC check function is enabled, do not enter CRC information in commands. Otherwise,

command errors may occur due to repeated CRC check.

The commissioning command to set the inverter whose address is 03H to be forward running is as

follows:

20 00

00 01

42 28

Inverter

Write

Parameter

Forward running

CRC

address command

address

Note:

1. Set the address (P14.00) of the inverter to 03.

2. Set "Channel of running commands" (P00.01) to "Communication", and set "Communication

channel of running commands" (P00.02) to the Modbus communication channel.

3. Click Send. If the line configuration and settings are correct, a response transmitted by the

inverter is received as follows:

20 00

00 01

42 28

Inverter

Write

Parameter

Forward running

CRC

address command

address

9.5 Common communication faults

Common communication faults include the following:

•

No response is returned.

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Goodrive350 Series High-performance Multi-function Inver ter. Operation manual - page 7