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KEB COMBIVERT F5-A,-E,-H 4.0. APPLICATION MANUAL (2008) - page 15

Positioning and Synchronous Control

7.12.2.1

Approach to reference point / modes

There are 3 different Modes of position reference:

PS.14 Mode of position reference

Bit

Meaning

Value

Explanation

0: off

No approach to reference point

1: no auto-

Approach to reference point is started via digital input. The input is

start

defined with PS.19.

The approach to reference point is carried out automatically during the

first "start positioning” command after "power on", even if the positio-

ning mode has not been activated yet (input with function "Positioning

/synchronous activation" not set). If the approach to reference point is

interrupted (e.g., by switching off the control release), all other "start

2: autostart

positioning" commands also start an approach to reference point. Has

the reference point search been completed once, no approach to re-

ference point can be initiated with "start positioning" anymore. If, addi-

tionally, an input is occupied with the function "approach to reference

point", this input is also active.

Mode of positi-

0/1

The software limit switches are active immediately (if programmed

on reference

in Pn. 66), the switching condition "approach to reference point com-

pleted" is met.The value for the actual position (ru.54) is generated as

follows:

● Encoder without absolute position information (e.g., incremen-

tal encoder): After "power on" the actual position is = the last acquired

3: last positi-

actual position before "power off". To ensure that the position is cor-

on (at power-

rect, the encoder may not turn anymore after power off.

on-reset)

● Encoder with single-turn absolute position information (e.g., re-

solver): After "power on", the position is read out by the encoder within

one revolution, the count of whole revolutions is taken from the last ac-

tual position before "power off". To ensure that the position is correct,

the encoder may turn maximally ½ revolution after power off.

● Encoder With multi turn absolute position information:

The current actual position is read from the encoder after "power on".

In mode 1 and 2, the approach to reference point is started on the rising edge of input "start approach to refe-

rence point" (mode 1) and "start positioning" (mode 2), respectively.

The approach to reference point starts at the speed set in PS.21 "reference speed". The direction of rotation

which is used first for the reference point search (the preferred direction f rotation) is set by the sign of PS.21 .

A positive sign means the drive first looks for the reference point switch in the clockwise direction of rotation.

The acceleration / deceleration ramps during the approach to reference point are defined via PS.20 "approach

to reference point ramp time" rather than the OP-parameters.

Attention: the ramp time and the approach to reference point speed must be chosen so that the drive can stop

and reverse as long as the reference point switch is active. Otherwise, faulty referencing can occur (e.g., stop

on the wrong side of the reference point).

To achieve the most precise referencing possible, an "approach to reference point free drive-speed" can be

programmed for free driving of the reference switch in PS.22 . If this parameter is set to "0:off", the free drive-

speed is taken as ¼ of the approach to reference point speed (PS.21) .

At the reference point, the actual position is overwritten with the value of PS.17 "reference point".

Page7.12 - 6

Positioning and Synchronous Control

The two following figures show an exemplary approach to reference point process. The further possibililties

programmable in PS.14 are shown later in this chapter.

Ref. point

search com-

pleted

Start

PS.21: Approach to ref.point

speed = positive

5/6

2/3

1

0

1000

2000

3000

4000

5000

6000

7000

8000

Limit switch left

Ref. point

Limit switch

switch

right

1

2

3

4

5

6

ru.02: Ramp

output display

ru.54: Actual

position

Approach to ref.

point completed

Target window

reached

Ref. point

switch

7

Start approach

to ref. point

1. PS.21 = positive, i.e., the drive accelerates with the ramp from PS.20 and searches in the direction of

clockwise rotation for the reference switch

2. Stopping at the reference switch

3. Free driving of the reference switch with free drive-speed (PS.21 / PS.22)

4. Stopping of the drive with ramp from PS.20

Setting of the signal "target window reached"

5. Wait for the damping period of 100ms

6. Overwrite the current actual position (ru.54) with the reference point position(PS.17)

Resetting of the signal "target window reached"

Setting of the signal "approach to reference point completed"

Stopping of the drive left of the reference point (programmable via PS.14)

Page7.12 - 7

Positioning and Synchronous Control

7.12.2.2

Approach to reference point / stopping point

PS.14 determines which side of the reference point switch the drive is positioned on after the approach to re-

ference point. Even if, after the free driving of the reference switch, positioning is to occur based on the zero

signal, "stopping point " determines if the first null signal is to be driven on at the right or left of the reference

switch.

The adjustment is only considered if the reference point switch serves not simultaneously as limit switch.

PS.14 Mode of position reference

Bit

Meaning

Value

Explanation

Stopping

0: right

Stop on the right side of the reference point switch

3

point

8: left

Stop on the left side of the reference point switch

7.12.2.3

Approach to reference point / stop at zero signal

An approach to reference point that depends only on the initiator signal of the reference point switch is insuf-

ficiently precise for many applications. Therefore, the possibility exists to couple the reference point with the

marker pulse of the encoder.

To that end, positioning after the free driving of the reference switch is done on the marker pulse of the encoder

and the current actual position=marker pulse is then overwritten with the reference point value.

With "stop at null signal= 4: yes" this function is activated.

Additionally, two monitoring functions can be switched in with bit 4 "error if no zero signal" and bit 8 "Verify zero

signal". These are only active if "stop at null signal= yes" is programmed.

PS.14 Mode of position reference

Bit

Meaning

Value

Explanation

0: no

The drive stops directly after free driving of the reference point switch.

The drive positions on the null signal of the encoder after free driving of

Stop at zero

2

the reference point switch at the free drive-speed. If during the drive to the

signal

4: yes

reference switch no null signal was received, the behaviour of the drive is

determined by bit 4 "error if no zero signal".

If, during the reference point search, no null signal is recognised, the drive

rotates maximally another two revolutions at the free drive-speed to locate

the null signal. If the null signal is found, the drive reverses and drives back

to the reference point switch. Positioning on the null signal is executed after

0: off

that.

Error, if no zero

If no null signal is recognised during the null signal search, the inverter re-

4

signal

ports "error! Encoder 1" respectively "error! Encoder 2" (E.EnC1 respectively

E.EnC2)

If, during the search for the reference point switch, no null signal is recogni-

sed (i.e., if the reference switch is reached before the encoder sends the first

16: on

marker pulse), the inverter immediately reports "error! encoder 1" and "error!

Encoder 2", respectively (E.EnC1 and E.EnC2, respectively).

0: off

no examination of the position of the null signal

The distance from switch to null signal is examined after driving free of the

Examine the

8

reference point switch. If the null signal does not lie within a range of ¼ to

zero signal

256: on

¾ revolutions, "error! Encoder 1" respectively "error! Encoder 2" (E.EnC) is

triggered.

Page7.12 - 8

Positioning and Synchronous Control

7.12.2.4

Approach to reference point / no driving free

Apart from the two modes "stop at null signal" or "stop after driving free" of the reference switch, there is a third

reference point drive mode:

PS.14 Mode of position reference

Bit

Meaning

Value

Explanation

The reference point switch is driven free during the approach to reference

0: off

point

As soon as the reference point switch has been hit, the drive stops on the

9

No driving free

switch. It does not matter whether the switch has been hit going in the

512: on

preferred direction. This setting may not be combined with "stop at null

signal".

7.12.2.5

Approach to reference point / limit switch

When the drive reaches the hardware limit switch for the direction of rotation, it automatically reverses and

begins searching the reference point in the

other direction of rotation.

If no reference point switch is found, the drive continuously shuttles between the two hardware limit switches.

Note: During the approach to reference point, the limit switch function works differently than in usual operation.

If the value "6: function turned off" is programmed in Pn.07 "Proh. rotation stopping mode", the drive reverses

with the acceleration and deceleration times defined in parameter PS.20 "reference acc/dec time".

For all other value of Pn.07, the setpoint speed without ramp is set to zero. The drive stops and then accele-

rates in the other direction of rotation with the ramp from PS.20. No normal quick stop is executed, and the

quick stop parameters (Pn.60 / Pn.61 / Pn.67) have no function.

7

Approach to

ref. point com-

pleted

Start

PS.21: Approach to ref. point

3/4

6/7

5

2

Speed = positive

1

0

1000

2000

3000

4000

5000

6000

7000

8000

Limit switch left

Ref. point

2

Limit switch

switch

right

Reversal after reaching the

right limit switch

Page7.12 - 9

Positioning and Synchronous Control

1

2

3

4

5

6

7

ru.02: Ramp

output display

ru.54: Actual

position

Limit switch

right

Approach to ref.

point completed

Target window

reached

Ref. point

switch

Start approach

to ref. point

1. PS.21 positive

Drive accelerates with ramp from PS.20 and seeks in clockwise direction of rotation for the reference

switch

2. Run-on to the limit switch

Reverse and seek in the other direction of rotation

3. Overdriving of the reference switch

(because stopping the drive left of the reference switch is chosen in PS.14, the switch must be hit from

the right)

4. Reversing and running onto the reference switch in direction of rotation clockwise

5. Reversing on the reference switch and driving free at free drive-speed (PS.21/ PS.22)

6. Stopping of the drive with the ramp from PS.20

Setting of the signal "target window reached"

Wait for the damping period of 100ms

7. Overwrite the current actual position (ru.54) with the reference point position(PS.17)

Resetting of the signal "target window reached"

Setting of the signal "approach to reference point completed"

Stopping of the drive left of the reference point (programmable via PS.14)

Page7.12 - 10

Positioning and Synchronous Control

7.12.2.6

Reference point / manual setting

7.12.2.6.1

Over PS.14

If no reference point switch is provided in the application, the drive can also be manually referenced:

PS.14 Mode of position reference

Bit

Meaning

Value

Explanation

0: off

No manual setting

The drive is approached in inching mode to reference point and then "ma-

nual setting = on" (bit 6) is set. The reference point position (PS.17) is

6

Manual setting

64: on

taken as the actual position (ru.54). The switching condition "approach to

reference point completed” (do.00...07, value 29) is set, the software limit

switch function can be used.

7.12.2.6.2

With input function "set reference point"

Independent of PS.14 "Mode of position reference" or PS.00 "position / synchronous mode", the actual position

ru.54 can be overwritten with the value of PS.17 "reference point" by setting a digital input.

To that end, an input must be selected in PS.13 "set reference point input selection".

(assignment of a digital input see chapter 7.3)

If this input set during an active positioning:

-

the inverter remembers the remaining path

-

the current position ru.54 is set to the reference point position PS.17

7

-

the inverter continues the interrupted positioning

7.12.2.7

Reference point / valid position

In order for the software limit switch function to be useable, an approach to reference point must be executed

prior to the positioning. In some cases (e.g., when using an absolute encoder), an approach to reference point

is, however, not required. By activation of bit 7 "the captured position is valid = yes", the drive is informed that

no approach to reference point is necessary.

PS.14 Mode of position reference

Bit

Meaning

Value

Explanation

0: no

Approach to reference point must be executed.

The captured

The actual position (ru.54) is declared "always valid". The switching condition

7

position is

128:

"approach to reference point completed” (do.00...07, value 29) is set, the soft-

valid

yes

ware limit switch function can be used.

Page7.12 - 11

Positioning and Synchronous Control

7.12.2.8

Approach to reference point / stop at index 0

By setting bit 5 (stop at index 0 = 32: on), it can be programmed that the drive automatically (i.e., without a "boot

positioning" signal) moves to the position from index 0 after completing the approach to reference point.

PS.20 "reference acc/dec time" specifies the acceleration / deceleration values for the positioning to index 0.

The maximum profile speed for positioning is determined for Index 0 by the value of PS.25 "index speed".

The drive remains at that Position. The setting "continue profile = yes” from index 0 is ignored.

PS.14 Mode of position reference

Bit

Meaning

Value

Explanation

0: off

After approach to reference point the drive stops at the reference point.

5

Stop at index 0

32: on

after approach to reference point, the position from Index 0 is driven to.

The following figure shows an approach to reference point with stop at the null signal left of the reference point

switch and automatic positioning to index 0:

1

2

3

4

5

6

7

8

ru.02: Ramp

outp. display

ru.54: Actual

position

Active approa-

che to ref. point

Target window

reached

Ref. point

switch

Start approache

to ref. point

1:

Start of approach to reference point

2.:

Run-on at the reference point switch

2 - 3: Reversing and free driving of the reference switch

3 - 4: Stop left of the reference switch

4:

Start of the positioning to the null signal of the encoder

5 - 6: Waiting out the damping period after reaching the null signal

6:

Referencing of the actual position: ru.54 is overwritten with the value of PS.17 "reference point"

6 - 7: Positioning to the target position of index 0 with the ramp time from parameter PS.20

7:

Reaching of the target position

8:

Approach to reference point finished

Page7.12 - 12

Positioning and Synchronous Control

7.12.3Synchronous mode

7.12.3.1

Synchronous mode / principle

The synchronous module realises an angle / speed synchronous control of a master drive (control drive) to one

or more slave drives. The control drive must not be closed-loop.

The master position is passed on to the slave. The master must therefore be equipped with an encoder inter-

face with incremental encoder output, and every slave with a second incremental encoder input.

Alternatively, the master can also be operated uncontrolled and the encoder signals of the master drive can be

connected directly to the slave.

The speed ratios are adjustable individually. The gear ratio is adjusted via the numerator / denominator ratio. If

the directions of rotation have to be different, a negative gear ratio has to be set.

For activated position controller, the slave is driven angular-synchronous, for deactivated position controller

(PS.06 = 0), speed-synchronous to the master drive.

The synchronous module contains other variants for synchronising (constant acceleration ramp or constant

synchronisation path) and a programmable angle correction.

The following mapping shows the general behaviour of synchronous control (without synchronisation pha-

ses):

oP.14/oP.15

ru.10

absolute

speed

Encoder 2

maximum

calculation

Ec.11

speed

ref. for / rev

Encoder 2

ru.02

(inc/r)

+

Ramp output

display

(setpoint speed for

Ec.01

+

speed controller)

encoder 1

(inc/r)

7

PS.09

Increments

Posi/synchronous

ru.56

of encoder

position limit

Set position

channel 2

Ec.14

Gear 2 nume-

+

PS.06 to

rator

PS.08

Position

Ec.15

-

controller

Gear factor

2 denominator

Increments

ru.54

of encoder

Actual

channel 1

position

Page7.12 - 13

Positioning and Synchronous Control

7.12.3.2

Synchronous mode / premise

For the synchronous module, the incremental signals from the encoder of the master drive must be passed on

to the slave.

Speed con-

Speed con-

Controlled

Speed con-

trolled master

trolled slave

master drive

trolled slave

drive

drive

drive

ENTER

START

FUNC.

ENTER

START

FUNC.

ENTER

START

FUNC.

ENTER

START

FUNC.

F/R

SPEED

F/R

SPEED

F/R

SPEED

F/R

SPEED

STOP

STOP

STOP

STOP

ANTRIEBSTECHNI K

ANTRIEBSTECHNI K

ANTRIEBSTECHNI K

ANTRIEBSTECHNI K

X3B X3A

X3B X3A

X3B X3A

3

3

3

3

~

~

~

~

If more than one slave is connected, there are two different variations for assembling the master-slave-chain:

direct transfer of the signals from the output of the master encoder interface to all slaves.

Page7.12 - 14

Positioning and Synchronous Control

Speed con-

Speed con-

Speed contolled

Speed con-

trolled slave

trolled

master drive

trolled

drive 2

slave drive X

slave drive 1

ENTER

START

FUNC.

ENTER

START

FUNC.

START

ENTER

START

FUNC.

F/R

SPEED

F/R

SPEED

ENTERF/R

FUNC.SPEED

F/R

SPEED

STOP

STOP

STOP

STOP

ANTRIEBSTECHNI K

ANTRIEBSTECHNI K

ANTRIEBSTECHNI K

ANTRIEBSTECHNI K

X3B X3A

X3B X3A

X3B X3A

3

3

3

3

~

~

~

~

Ec.20 Encoder operating mode = 1

Ec.20 Encoder operating mode = 0

(Input + without terminating resistor)

(Input + with terminating resistor)

Disadvantages:

-

Limitation of the number (max. 10, after RS.422 specification)

-

No guarantee of an EMC conform installation (adapter required for distribution, no off-the-shelf cables

available), therefore, the second variant is preferable:

7

Advantages:

-

The incremental signals are processed. Thus, no limitation of the number of the connected slaves

-

off-the-shelf cables available that guarantee EMC compliant assembly. Further information on available

components can be found at wow.keb.de => Service & Downloads

-

Error control for processed master signal integrated in repeater

Page7.12 - 15

Positioning and Synchronous Control

7.12.3.4

Synchronous mode / position normalisation

Via parameter PS.01 act. master source, the channel from which the slave receives the master position is

selected.

This must be encoder channel 2 for most applications. (Off-the-shelf cables and a terminating resistor that can

be switched off exist only for channel 2 ).

Figure 7.12.3.4 Position normalisation

Speed con-

Speed con-

The adjoining figure shows a typical

trolled master

trolled slave

synchronous application.

drive

drive

If the load of the master drive has travelled

one

revolution, the load of the slave should also

have travelled one revolution (in the oppo-

ENTER

START

FUNC.

ENTER

START

FUNC.

F/R

STOP

SPEED

F/R

STOP

SPEED

site direction).

This is the case for, e.g., printing presses

or

rolling machines.

ANTRIEBSTECHNI K

ANTRIEBSTECHNI K

X3B X3A

X3B X3A

3

3

~

~

i= 5,25

i= 15

Load

Load

Direction of ro-

Direction of ro-

tation clockwise

tation counter-

clockwise

In parameter ru.54 "actual position", the slave position (i.e., the number of increments from the slave motor) is

displayed. In ru.54, one revolution of the slave load corresponds to:

Ec.01 "encoder 1 (inc/r)" x gear factor slave

The master position is displayed in parameter ru.56 "set position". The display occurs in increments and is

converted to the slave position. The conversion takes into account the ratio of the increments per revolution of

the encoder and the relation of the two gear factors. If the master is connected to encoder channel 2, the gear

factor of the slave must be entered in parameter Ec.14 "gear 2 numerator" and the gear factor of the master

must be entered in parameter Ec.15 "gear 2 denominator" for the conversion of the gear ratios.

Page7.12 - 16

Positioning and Synchronous Control

Since only integer values can be set, the gear factors must be expanded correspondingly

(15 : 5,25 becomes 1500 : 525).

Display in ru.56 (master position converted to slave units):

Ec.01

Ec.14 (gear factor slave)

number increments master x

———

x

———————————————

Ec.11

Ec.15 (gear factor master)

An inversion of the rotation direction of the slave compared to the master drive is achieved by setting a negative

value for Ec.14.

Example (adjustments for figure 7.12.3.3 position normalisation):

"Normal" vector controlled operation is programmed in the master, the synchronous module is not activated.

For the slave, encoder channel 1 serves as speed feedback and encoder channel 2 as master position infor-

mation. Both load shall be moved angular-synchronous, but in opposite direction of rotation.

Adjustment in the slave:

-

PS.00 "Posi / synchronous mode" = synchronous mode

-

CS.01 "Actual source" = channel 1

-

PS.01 "Actual master source" = channel 2

-

PS.06 "KP for positioning / synchronous" ≠ 0

-

Ec.14 "Gear 2 numerator" = -1500

-

Ec.15 "Gear 2 denominator" = 525

7

Typically, an approach to reference point is executed for the slave drive before the start of the synchronous

running, to create the relation between the position display of the slave drive and the mechanics of the appli-

cation.

The relation between master and slave position is created only with the activation of the synchronous module.

At the time of activation, the master position (= ru.56 "set position") is set equal to the slave position (= ru.54

"actual position").

7.12.3.5

Synchronous mode / selection of operating mode

The operating mode synchronous mode is selected via parameters PS.00 bit 0...3 or via the control word (Sy.43

or Sy.50)

PS.00: Posi / synchronous mode

Bit

Meaning

Value

Explanation

0: off

no special operation selected

1:

Synchronous

Selection of operating mode "synchronous mode"

mode

Posi / synchro-

0..3

2...6

Without function for synchronous mode

nous mode

The operating modes (synchronous running, positioning mode

7: Via control word

or contouring control) are selected via the control word (Sy.43

or Sy.50).

Page7.12 - 17

Positioning and Synchronous Control

If PS.00 bit 0..3 contains the value 7:

Sy.50: control word (low) / Sy.43: control word (long)

Bit

Meaning

Value

Explanation

0: off

4096: Synchro-

Selection of operating mode synchronous running

Operating

nous running

12/13

mode

8192: Positioning

Selection of operating mode positioning

12288: Contou-

Selection of operating mode contouring control

ring control

PS.00 can only be written if the modulation is switched off, Sy.50 can always be written. The synchronous mo-

dule must be activated by an input. Which input is to be used is determined via parameter PS.02 "posi / sync

input selection".

7.12.3.6

Synchronous mode / activation and synchronization

7.12.3.6.1

Principle

With the activation of the synchronous module, the relation between master position and slave position is es-

tablished.

Activation means:

-

Synchronous mode is selected in parameter PS.00,

-

Modulation is enabled,

-

the digital input for activation of the synchronous operation is set.

At the time of activation, the starting synchronisation begins.

Gear factor changes, angle correction or similar may not be execut-

Attention:

ed during the synchronisation.

The synchronous module is not deactivated by switching of the modulation. The angle difference is continuous-

ly calculated, and, after again switching on the modulation, a synchronisation with ramps is always carried out

(independent of the type of initial synchronisation).

The type of the synchronisation at activation of the synchronous running is determined by the setting of "acce-

leration time forward (oP.28)" in parameter PS.00 "position / synchronous mode" and by the parameter PS.05

"start offset" .

7.12.3.6.2

Synchronization at limit

For synchronisation at the torque limit, the starting ramp must be deactivated.

PS.00: Posi / synchronous mode

Bit

Meaning

Value

Explanation

Synchronous running / star-

No starting ramp for synchronisation at the start of the synchro-

10

0: off

ting ramp (oP.28)

nous running.

Furthermore, the value 0 must be set in parameter PS.05 "start offset".

Page7.12 - 18

Positioning and Synchronous Control

This parametrisation is only reasonable if master and slave rotate at the same speed at the start of the syn-

chronous operation, so that a synchronisation is unnecessary. If the speeds are different, the synchronisation

occurs in the following manner:

At activation of the synchronous mo-

ru.56: Set position

dule, the set point position is set to the

(master position)

actual position.

ru.54: Actual positi-

The setpoint speed of the slave is set

on (slave position)

PS.05:

Start-

to the actual speed of the master.

offset

The difference to the master position is

corrected by the position controller.

Maximum speed of the slave:

Actual speed

master

(converted with

Master speed + PS.09

gear ratio)

The switching condition "drive running

Act. speed slave

synchronously" is met with activation

Angle difference >

of the synchronous mode.

level

Drive runs synchro-

To recognize the instant at which both

nous

drives are actually running synchro-

Activate posi/ syn-

nously, the switching condition "angle

chronous running

Time

difference < level" must be linked with

the signal "drive running synchronous-

ly".

7

7.12.3.6.3

Synchronization with constant path

For the synchronisation within a constant path, the starting ramp must be deactivated.

PS.00: Posi / synchronous mode

Bit

Meaning

Value

Explanation

Synchronous running / star-

No starting ramp for synchronisation at the start of the syn-

10

0: off

ting ramp (oP.28)

chronous running.

The path which the master traverses during the synchronisation is entered in parameter PS.05 "starting offset".

The slave drive calculates internally the acceleration / deceleration times with which it reaches the master

speed within the adjusted path. If the master has traversed the programmed path, the master position is set to

the slave position.

Example:

Let the master speed be 1500 rpm. Let the encoder type be an incremental encoder with 2500 pulses. Let

"multiple evaluations" be set to the value "2:4-fold".

This results in 10000 increments / revolution * 1500 U / 60s = 250000 increments/ s

Page7.12 - 19

Positioning and Synchronous Control

If the value 250000 increments is set in PS.05, the slave must also accelerate to the master speed

in 1s. The disadvantages of this type of initial synchronization are as follows:

-

The synchronisation path is set via parameter PS.05 "start offset", making it difficult to realise an

offset between master and slave at the start.

-

Checking whether the synchronisation was successful is not possible. If the slave drive cannot fol-

low the calculated ramp (e.g., due to reaching the torque limit), the master position is still set to the

slave position. The angle synchronicity is lost thereby (For the example above, the connection to the

position of the switch "activate synchronous running" would be lost). The switching condition "drive

running synchronously" is also still set in spite of the angle error.

-

Even if the slave drive can generally follow, system deviations can distort the accuracy of the angle-

synchronous running.

At the activation of the synchronous module,

ru.56: Set position

3000

the master position (set point position) is set

(master position)

to 0.

2000

ru.54: Act. position

When the master has completed the path

(slave position)

1000

programmed in PS.05, the master position is

PS.05:

set to the slave position.

Startoffset

0

Actual speed

master

The slave drive calculates the acceleration /

(converted with

deceleration ramps it needs to reach the ma-

gear ratio)

ster in this time.

The ramp time also depends on the master

Act. speed slave

speed and the value in PS.05.

After the master has completed the path

Angle difference >

level

PS.05, the master position (set point position)

is overwritten with the slave position (actual

Drive runs synchro-

position).

nous

Activate posi/ syn-

chronous running

Time

Page7.12 - 20

Positioning and Synchronous Control

7.12.3.6.4

Synchronization with ramp

The synchronisation with ramp is the most comfortable method for the initial synchronization. It is always used

for

synchronisation after interruption of the synchronous running due to switching off the modulation.

PS.00: Posi / synchronous mode

Bit

Meaning

Value

Explanation

Synchronisation at the start of the synchronous running with

Synchronous running /

10

1024: off

the ramp times for acceleration / deceleration, clockwise ro-

starting ramp (oP.28)

tation

With activation of the synchronous module, the master position (set position ru.56) is set to the slave position

(actual position ru.54).

The slave accelerates with the predefined ramps, to follow the master.

Because of the differing speeds of master and slave, an angle difference occurs. This missing distance to re-

aching the master position is made up for by increasing the slave speed beyond the master speed. The slave

calculates a setpoint speed profile, which allows it to make up for the angle difference.

Maximum speed for this setpoint profile is the maximum reference oP.10 / oP.11. If the drive cannot follow the

setpoint speed profile, the remaining angle difference is eliminated by the position controller. Therefore, the

maximum speed during the synchronisation phase is oP.10 / oP.11 + position controller limit PS.09. This value

is still limited by the absolute maximum reference (oP.14 / oP.15).

At the start of the synchronous running, the ma-

ster position (set position ru.56) is set to the sla-

ve position (actual position ru.54).

ru.54: Act. position

(slave position)

The slave accelerates and makes up for the lost

7

distance.

The ramps must be adjusted so that the slave

ru.56: Set position

drive can follow without reaching the torque li-

(master position)

mits.

Actual speed

The switching condition "drive running synchro-

master

nously" is set if the calculated setpoint speed

(converted with

profile for reaching the master position is com-

gear ratio)

pleted.

Act. speed slave

If, e.g., the torque limit is reached, angle syn-

chronicity is not given at that time.

Angle difference >

If achievement of a specific angle accuracy has

level

to be checked, the switching condition "drive run-

Drive runs synchro-

ning synchronously" must be linked with the swit-

nous

ching condition "angle difference < level".

Activate posi/ Syn-

chronous running

Time

As soon as the slave reaches the last phase of the synchronisation

(that means: the last deceleration and

acceleration to the master speed, respectively) the ramp can deviate from the programmed values. This is the

case if the master speed is not constant, i.e., if adjustments still have to be made during the running-in. Adjust-

ments of the value for acceleration or deceleration are not accepted anymore during this phase.

Additionally, an offset can be entered in parameter PS.05 "start offset" to run the master offset to the slave . The

master position is set to the value slave position - PS.05 upon activation of the synchronous running.

That means: ru.56 = ru.54 - PS.05 (at the time of activation)

Page7.12 - 21

Positioning and Synchronous Control

1 = Material holder (master)

2 = Tool holder (slave)

Incremental encoder

Incremental encoder

1024 Increments per revolution

2500 Increments per revolution

10 cm according to one motor revolution

10 cm according to one motor revolution

Switch to acti-

Switch to deac-

vate synchro-

tivate synchro-

nous running

nous runnning

Activation of the

synchronous

1

cm

running

0

10

2

30

40

50

60

70

80

Start of action

(drilling)

1

cm

2

0

10

20

30

40

60

70

80

End of action

1

(drilling)

cm

0

10

20

30

40

50

2

70

80

The master drive is a material carrier (e.g., a conveyor belt), on which materials (e.g., boards) are transported

at variable speed.

The leading edge of the material crosses an indicator and thereby activates the synchronous running of the

slave drive.

The slave is a tool carrier (transporting, e.g., a drill drive). As long as there is no board, it remains at a defined

resting position (20 cm).

The hole should be drilled 5cm from the front edge while the conveyor is running.

The slave must run absolutely angular-synchronously to the master during the drilling.

When the board reaches the 2. switch, the drilling process must be safely concluded. The synchronous running

is deactivated and the slave can now (e.g., in positioning operation) run back to the starting position.

From the activation of the synchronous running to the start of the drilling, the master must travel 50cm and the

slave 30cm.

In parameter PS.05 "start offset", therefore, an offset of 20cm, converted to increments, must be entered.

For the example

-

10cm = 3 motor rotations => 20cm = 6 motor rotations

above:

-

2500 encoder / 4-fold evaluation => 10000 increments per revolution

-

PS.05 = 6 * 10000 = 60000 increments

During the phase of acceleration to the master speed, the slave travels at the average speed:

initial speed, slave + (master speed - initial speed, slave)

————————————————————————————

2

In our example:

let the real master speed be 500 rpm

the master needs 1 motor revolution for 10cm, the slave 3 motor revolutions

=> Ec.14 = 3000 / Ec.15 = 1000

Page7.12 - 22

Positioning and Synchronous Control

The master speed converted to the slave standardisation is therefore 1500 rpm.

The slave speed at the start is zero. Let the acceleration time be 0.2s (per 1000 rpm).

For the acceleration from 0 to 1500 rpm the slave therefore needs 0.3s. The mean speed in the acceleration

phase is 750 rpm = 12.5 U/s. Each revolution corresponds to 10,000 increments.

This results in an acceleration path of:

12,5 U/s x 10000 increments / U x 0,3s = 37500 increments

The master (converted to slave standardisation) constantly runs at 1500 rpm = 75000 increments in 0.3s. The

difference between master and slave is 37500 increments. PS.05 is 60000 increments.

The slave must therefore wait until the master has travelled another 22500 increments and then synchronises

itself without overshooting according to the adjusted ramp.

Master and slave are running at the correct offset angle after 37500 increments = 3.75 revolution = 12.5 cm of

the slave. They are, therefore, synchronous starting at the drill head position 32.5cm.

7.12.3.7

Gear factor

The gear factor between master and slave is entered in the parameters for the encoder channel connected to

the master position. Normally, this is encoder channel 2. Therefore, the gear factor must be entered in Ec.14

(or Ec.58, respectively) "gear 2 numerator" (= gear factor of the slave) and Ec.15 (or Ec.59, respectively) "gear

2 denominator" (= gear factor of the master).

The gear factor is not set-programmable. If it is to be adjusted set-dependently, this can be implemented by

appropriately setting the analog parameters (see chapter 7.15.9). As the source, the value "1: motor potentio-

meter" must be chosen in An.53. The motor potentiometer value (oP.52) is set-programmable.

Control by means of an analog channel is also possible via the analog parameter settings.

7

The new gear factor during the active synchronous operation changes (at equal actual speed of the master

drive) the master speed expressed in the scale of the slave. Due to the now different

speeds of master and slave, an angular offset is created and the slave must be synchronised again:

PS.00: Posi / synchronous mode

Bit

Meaning

Value

Explanation

The slave carries out the new synchronisation using the acceleration /de-

celeration times for clockwise rotation. The sequence corresponds to the

initial synchronisation with ramps (see instructions in item 7.12.3.5.4),

0: on

Synchronous

only that the parameter PS.05 "start offset" has no effect. The treatment

running / gear

of the switching condition "drive running synchronously" corresponds to

11

factor ramp

the behaviour during initial synchronisation with ramps.

(oP.28)

The slave carries out the synchronisation without ramps at the speed /

torque limit. This setting can be useful if the gear factor is changed con-

2048: off

tinuously via the analog channel. The switching condition "drive running

synchronously" remains set.

If the gear factor change is smaller than 0.5%, the change is applied without ramp.

Page7.12 - 23

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