EMERSON PACSystems VersaMax MICRO PLC & NANO PLC. USER MANUAL (2019)

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Figure 233

The main program is level 1. The program can include up to eight additional nested call
levels.

21.2.1

Declaring a Subroutine

A subroutine must be declared through the block declaration editor of the programming
software.

21.2.2

Calling a Subroutine

A subroutine invoked in the program is using a CALL instruction. Up to 64 subroutine block
declarations are allowed for Micro CPUs. Up to 8 subroutine block declarations are allowed
for NANO CPUs. Regardless of the CPU model, 64 CALL instructions are allowed for each
block in the program.

Figure 234

21.2.3

Locking/Unlocking Subroutines

Subroutine blocks can be locked and unlocked from the programming software. There are
four levels of locking:

Type of Lock

Description

View

When locked, the subroutine cannot be viewed.

Edit

When locked, the information in the subroutine cannot be changed.

Perm View

The subroutine is permanently locked and cannot be unlocked.

Perm Edit

The subroutine is permanently locked and cannot be unlocked.

Permanently locked subroutines cannot be unlocked, even if the program is copied, backed
up, or restored. A previously view-locked or edit-locked subroutine can be unlocked.

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21.3

Program Languages

Application programs for VersaMax Nano PLCs and Micro PLCs can be created in Ladder
Diagram or Instruction List format.

21.3.1

Ladder Diagram

This traditional PLC programming language, with its rung-like structure, executes from top

to bottom. The logic execution is thought of as “power flow”, which proceeds down along
the left “rail” of the ladder, and from left to right along each rung

in sequence.

Figure 235

The flow of logical power through each rung is controlled by a set of simple program
functions that work like mechanical relays and output coils. Whether or not a relay passes
logical power flow along the rung depends on the content of a memory location with which
the relay has been associated in the program. For instance, a relay might pass power flow if
its associated memory location contained the value 1. The same relay would not pass power
flow if the memory location contained the value 0.

If a relay or other function in a rung does not pass logical power flow, the rest of that rung is
not executed. Power then flows down along the left rail to the next rung.

A rung contains complex functions that can be used for operations like moving data stored
in memory, performing math operations, and controlling communications between the
Micro PLC and other devices in the system.

Some program functions, such as the Jump function and Master Control Relay, can be used
to control the execution of the program itself.

Together, this large group of Ladder Diagram relays, coils, and functions is called the

“Instruction Set” of the Micro PLC.

21.4

The Instruction Set

A VersaMax Nano PLC or Micro PLC provides a powerful Instruction Set for building
application programs.

As a guide to the programming capabilities of the VersaMax Micro PLC, all of the relays, coils,
functions, and other elements of the Instruction Set are listed on the following pages.
Complete reference information is included in Chapter 23: and in the online help for the
programming software.

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21.4.1

Contacts

–

| |

–

Normally Open

Passes power if the associated reference is ON.

–

|/|

–

Normally Closed Passes power if the associated reference is OFF.

–

|+|

–

Continuation

Passes power to the right if the preceding continuation coil is set ON.

21.4.2

Coils

–

( )

–

Normally Open Sets the associated reference ON if the coil receives power. Otherwise

OFF.

–

(/)

–

Negated

Sets the associated discrete reference ON if the coil does not receive
power. Otherwise OFF.

–

( )

–

Positive
Transition

If power flow was OFF to this coil the last time it was executed and is
ON this time, then the coil is turned ON. Otherwise, the coil is turned
OFF.

–

( )

–

Negative
Transition

If power flow was ON to this coil the last time it was executed and is
OFF this time, then the coil is turned ON. Otherwise, the coil is turned
OFF.

–

(S)

–

SET

Sets the associated discrete reference ON if the coil receives power. It
remains set until reset by an

–

(R)

–

coil.

–

(R)

–

RESET

Sets the associated discrete reference OFF if the coil receives power. It
remains reset until set by an

–

(S)

–

coil.

–

(SM)

–

Retentive SET

Sets the associated reference ON if the coil receives power. The
reference remains set until reset by an

–

(RM)

–

coil. Its state is retained

through power failure and STOP-TO-RUN transition.

–

(RM)

–

Retentive

RESET

Resets the associated discrete reference OFF if the coil receives power.
The reference remains reset until set by an

–

(SM)

–

coil. Its state is

retained through power failure and STOP-TO-RUN transition.

–

(/M)

–

Negated

Retentive

Sets the associated discrete reference ON if the coil does not receive
power. The state is retained through power failure and STOP-TO-RUN
transition. Otherwise OFF.

–

(M)

–

Retentive

Sets the associated discrete reference ON if the coil receives power.
The state is retained through power failure and STOP-TO-RUN
transition. Otherwise OFF.

–

(+)

–

Continuation

If power to the coil is ON, the continuation coil sets the next
continuation contact ON. If power is OFF, the continuation coil sets the
next continuation contact OFF.

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21.4.3

Timers and Counters

ONDTR On-Delay

Stopwatch Timer

Accumulates time while receiving power. The current value is reset
to zero when the reset input receives power.

OFDT

Off-Delay Timer

Accumulates time while NOT receiving power. The current value is
reset to zero when there is power flow.

TMR

On-Delay Timer

Accumulates time while receiving power. The current value is reset
to zero when there is no power flow.

UPCTR Up Counter

Increments by 1 each time the function receives transitional power.

DNCTR Down Counter

Counts down from a preset value every time the function receives
transitional power.

21.4.4

Math Functions

ADD

Addition

Adds two numbers.

SUB

Subtraction

Subtracts one number from another.

MUL

Multiplication

Multiplies two numbers.

DIV

Division

Divides one number by another, yielding a quotient.

MOD

Modulo Division

Divides one number by another, yielding a remainder.

EXPT

Power of X

Raises X to the power specified by IN and places the result in Q.

SIN

Sine

Finds the trigonometric sine of a real number.

COS

Cosine

Finds the trigonometric cosine of a real number.

TAN

Tangent

Finds the trigonometric tangent of a real number.

ASIN

Inverse Sine

Finds the inverse sine of a real number.

ACOS

Inverse Cosine

Finds the inverse cosine of a real number.

ATAN

Inverse Tangent

Finds the inverse tangent of a real number.

DEG

Convert to Degrees Performs a RAD_TO_DEG conversion on a real radian value.

RAD

Convert to Radians Performs a DEG_TO_RAD conversion on a real degree value.

SCALE Scaling

Scales an input constant or word value.

SQRT

Square Root

Finds the square root of an integer or real value.

LOG

Base 10 Logarithm Finds the base 10 logarithm of a real value.

Natural Logarithm Finds the natural logarithm base of a real number.

EXP

Power of e

Raises the natural logarithm base to the power specified by input.

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21.4.5

Relational Functions

Equal

Tests for equality between two numbers.

Not Equal

Tests for non-equality between two numbers.

Greater Than

Tests whether one number is greater than another.

Greater Than or Equal
To

Tests whether one number is greater than or equal to another

Less Than

Tests whether one number is less than another.

Less Than or Equal To

Tests whether one number is greater than or equal to another.

RANGE Range

Test the input value against a range of two numbers.

21.4.6

Bit Operation Functions

AND

Logical AND

Performs Logical AND of two bit strings.

Logical OR

Performs Logical OR of two bit strings.

XOR

Logical Exclusive OR Performs Logical Exclusive OR of two bit strings.

NOT

Logical Invert

Performs a logical inversion of a bit string.

SHL

Shift Left

Shifts a bit string left.

SHR

Shift Right

Shifts a bit string right.

ROL

Rotate Left

Rotates a bit string left.

ROR

Rotate Right

Rotates a bit string right.

BIT_TEST

Bit Test

Test a bit within a bit string to determine whether that bit is
currently 1 or 0.

BIT_SET

Bit Set

Sets one bit within a string to true.

BIT_CLR

Bit Clear

Sets one bit within a string to false.

BIT_POS

Bit Position

Locates a bit set to true within a bit string.

MASK_COMP Masked Compare

Performs a masked compare of two arrays.

21.4.7

Data Move Functions

MOVE

Move

Moves one or more bits of data.

BLKMOV

Block Move

Moves a block of up to 7 constants.

BLK_CLR

Block Clear

Clears to zero one or more bytes/words of memory.

SHFR

Shift Register

Shifts one or more words or bits of data through a block
of memory.

BIT_SEQ

Bit Sequencer

Sequences a 1 through a group of bits in PLC memory.

COMMREQ

Communication
Request

Sends a communications request.

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21.4.8

Table Functions

ARRAY_MOVE Array Move

Copies a specified number of data elements from a
source array to a destination array.

SEARCH_EQ

Search Equal

Searches array for values equal to a specified value.

SEARCH_NE

Search Not Equal

Searches array for values not equal to a specified value.

SEARCH_GT

Search Greater Than

Searches array for values greater than a specified value.

SEARCH_GE

Search Greater Than or
Equal

Searches array for values greater than or equal to a
specified value.

SEARCH_LT

Search Less Than

Searches array for values less than a specified value.

SEARCH_LE

Search Less Than or
Equal

Searches array for values less than or equal to a
specified value.

21.4.9

Conversion Functions

INT_TO_BCD4

Convert to BCD-4 (From INT)

Converts a number to 4-digit BCD format.

REAL_TO_WORD Convert to Word (From REAL) Converts a Real value to Word format.

BCD4_TO_INT
BCD4_TO_REAL

Convert to INT (From BCD-4 or
REAL)

Converts a number to signed integer format.

BCD4_TO_DINT
REAL_TO_DINT

Convert to DINT
(From BCD-4 or REAL)

Converts a number to double precision integer
format.

INT_TO_REAL
DINT_TO_REAL
BDC4_TO_REAL
WORD_TO_REAL

Convert to Real
(From INT, DINT, BCD-4 or
WORD)

Converts a value to real value format.

REAL_TO_INT

Truncate to INT (from REAL)

Truncates to a 16-bit signed number. The
range is

–

32,768 to +32,767.

REAL_TO_INT

Truncate to Double Precision
INT (from REAL)

Truncates to a 32-bit signed number. The
range is -2,147,483,648 to +2,147,483,647.

21.4.10

Control Functions

CALL

Call

Causes a program execution to go to a specified
subroutine block.

DO_IO

Do I/O

Services a specified range of inputs or outputs
immediately (all inputs or outputs on a module will be
serviced if any addresses on that module are included
in the function

–

partial I/O module updates are not

performed

PID_IND

Independent PID Algorithm Selects the non-interacting independent PID algorithm.

PID_ISA

ISA PID Algorithm

Selects the ISA PID algorithm.

END

Temporary End of Logic

The program executes from the first rung to the last
rung or the END instruction, whichever is encountered
first. This instruction is useful for debugging purposes.

COMMENT Comment

A rung explanation.

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SVCREQ

Service Request

A special PLC service function.

MCRN

Master Control Relay

Starts a master control relay range. An MCR causes all
rungs between the MCR and its subsequent ENDMCR to
be executed with no power flow. Up to 8 MCRs can be
nested.

ENDMCR

End Master Control Relay

Ends a master control relay range.

JUMP

Jump

Jumps to a specified location indicated by a LABEL in
the logic.

LABEL

Label

The target location of a JUMP instruction. Multiple
Jump instructions can reference the same label.

DRUM

Drum Sequencer

Operates like a mechanical drum sequencer, selecting a
16-bit output pattern from an array of stored patterns,
and sending it to a set of outputs.

21.4.11

Communication Function

MODBUS_TCP_RW MODBUS/TCP

read/write

Processes read and write requests for MODBUS/TCP
Client support

21.4.12

Motion Functions

FIND_HOME

Find Home

Defines a Home (zero) position for an axis.

GO_HOME

Go Home

Moves the motor to a position that has been
defined by the Find Home function.

JOGGING

Jogging

Jogs the axis backward or forward at the specified
acceleration and velocity.

BLENDING

Blending

Executes up to four successive moves without the
distance and velocity output values retuning to zero
between moves.

STOP_MOTION

Stop Motion

Stops all motion on the channel while leaving the
channel active.

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Chapter 22:

Program Data and References

This chapter describes the types of data that can be used in an application program, and
explains how that data is stored in memory by a VersaMax Nano PLC or VersaMax Micro PLC.

•

Data memory references

•

Fixed I/O map locations

•

Retentiveness of data

•

System status references

•

Time tick contacts

•

How program functions handle numerical data

22.1

Data Memory References

Data in PLC programs is referenced by memory addresses that specify both a memory type
and a precise address within that memory type. For example:

%I00001

specifies address 1 in Input memory.

%R00256

specifies address 256 in Register memory.

The letter prefix indicates where data is stored in PLC memory.

22.1.1

Memory Allocation

The following table shows the types and sizes of available memory in VersaMax Micro and
Nano PLCs. (See Appendix B: for a further comparison with the Series 90 Micro PLC.)

Reference Type

Reference Range 10-Point

Nano PLCs

14-
Point
Micro
PLCs

23- and
28-Point
Micro
PLCs

20-/40-
/64-Point
Micro
PLCs

User program logic

Not applicable

2K words

9K words 9K words

48K bytes

Discrete inputs

%I0001 - %I0512

512 bits

512 bits 512 bits

512 bits

Discrete outputs

%Q0001 - %Q0512

512 bits

512 bits 512 bits

512 bits

Discrete global
references

%G0001 - %G1280

1280 bits

1280 bits 1280 bits

1280 bits

Discrete internal coils

%M0001 - %M1024

1024 bits

1024 bits 1024 bits

1024 bits

Discrete temporary coils %T0001 - %T0256

256 bits

256 bits 256 bits

256 bits

System status
references

%S0001 - %S0032
%SA0001 - %SA0032
%SB0001 - %SB0032
%SC0001 - %SC0032

32 bits
32 bits
32 bits
32 bits

System register
references

%R0001 - %R0256 or
%R0001 - %R2042

256 words

256
words

2K words

32640
(close to
32k) words

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Reference Type

Reference Range 10-Point

Nano PLCs

14-
Point
Micro
PLCs

23- and
28-Point
Micro
PLCs

20-/40-
/64-Point
Micro
PLCs

Analog and High-Speed
Counter inputs

%AI0001 - %AI0128

128 words 128

words

128 words 128 words

Analog outputs

%AQ0001 -
%AQ0128

128 words 128

words

128 words 128 words

* For viewing only; cannot be referenced in a user logic program.

22.1.2

Word Memory References

Each word memory address (reference) is on a 16-bit word boundary. The PLC uses three
types of references for data stored in word memory.

%AI

Normally used for analog inputs

%AQ

Normally used for analog outputs.

Registers are normally used to store program data in word format.

An example is represented below. The example shows ten addresses. Each has 16 bits that
together contain one value. The PLC cannot directly access individual bits in word memory.

%R Addresses

Example Value

0001

12467

0002

12004

0003

231

0004

359

0005

0006

882

0007

0008

771

0009

735

0010

0000

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22.1.3

Bit Memory References

The PLC uses six types of references for data stored in bit memory.

Normally used for discrete inputs, and viewable in the Input Status Table.

Normally used for physical output references, and viewable in the Output Status Table. A
%Q reference may be either retentive or non-retentive, depending on its use in the
program.

Normally used to represent internal references. A specific %M reference may be either
retentive or non-retentive, depending on its use in the program.

Used for temporary references that can be used many times in a program. Data with %T
references is not retained through loss of power or RUN-TO-STOP-TO-RUN transitions.
%T references cannot be used with retentive coils.

System status references, which have specific predefinitions.
%S, %SA, %SB, and %SC can be used for any type of logic contact.
%SA, %SB, and %SC can be used for retentive coils.
%S can be used as inputs to functions or function blocks.
%SA, %SB, and %SC can be used as inputs or outputs of functions and function blocks.

Used for Global Data. Data in %G references is retained through power loss. %G
references can be used with contacts and retentive coils, but not on non-retentive coils.

Each bit memory address (reference) is on a bit boundary. Data is stored in bit memory as
represented below. The example shows 160 individually addressed bits, with address 1 in
the upper left and address 160 in the lower right.

Figure 236

Transition Bits and Override Bits

%I, %Q, %M, and %G references have associated transition and override bits.

%T, %S, %SA, %SB, and %SC references have associated transition bits only.

The CPU uses transition bits for transitional coils. When override bits are set, the
associated references can only be changed from the programmer.

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22.2

Fixed I/O Map Locations

A Nano/Micro PLC automatically reserves some memory locations for specific functions. Use
of these addresses for other purposes is not recommended.

22.2.1

Reserved Bit Memory Locations: %I

Micro PLCS (14- thru 64-Point)

Nano PLCs (10-Point)

Address

Standard
Inputs

4 Type A
Counters

1 Type A and
1 Type B

Standard
Inputs

3 Type A
Counters

1 Type A and
1 Type B

0001

Input 1

Count 1

Type B counter
(Phase 1)

Input 1

Count 1

Type B counter
(Phase 1)

0002

Input 2

Preload/Strobe 1
or Home Input 1

Not used

Input 2

Preload/
Strobe 1

Not used

0003

Input 3

Count 2

Type B counter
(Phase 2)

Input 3

Count 2

Type B counter
(Phase 2)

0004

Input 4

Preload/Strobe 2
or Home Input 2

Not used

Input 4

Preload/
Strobe 2

Preload/Strobe for
Type B counter

0005

Input 5

Count 3

Not used

Input 5

Count 3

Type A counter:
Count Input

0006

Input 6

Preload/Strobe 3
or Home Input 3

Preload/Strobe
for Type B

Input 6

Preload/
Strobe 3

Type A counter:
Preload/Strobe

0007

Input 7

Count 4

Type A counter:
Count 4

0008

Input 8

Preload/Strobe 4
or Home Input 4

Preload/
Strobe 4

0009-16

Inputs for 23-/28-point Micros, Default first discrete input for 14-pt PLCs, configurable.

0017

Default first discrete input from expansion unit (28/23pt PLCs), can be reconfigured.

0488

Micro 20-, 40-, 60-: Ethernet Option Module
configured for Modbus/TCP Client operation.

0494 to 0496 Pulse Train Complete for channels 1 to 3

Pulse Train Complete for channels 1 to 3

0497 to 0499 Strobe status bits for channels 1 to 3

Strobe status bits for channels 1 to 3

00500

Strobe status bit for channels 4

0501 to 0503 Preload status bits for channels 1 to 3

Preload status bits for channels 1 to 3

0504

Preload status bit for channel 4

0505 to 0507 Output status bits for channels 1 to 3

Output status bits for channels 1 to 3

0508

Output status bit for channel 4

0511

Pulse Train Complete for channel 4

0512

Counter Error status

%I0002, I0004, I0006, and I0008 are reserved as Home Inputs only for Micro-20, -40, and

–

64 CPUs that are configured for 32-bit

counter operation (either 4 Type A Counters, 32 bits, or 1 Type A and 1 Type B counter 32 bits).

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22.2.2

Reserved Bit Memory Locations: %Q

Micro PLCS (14- thru 64-Point)

Nano PLCs (10-Point)

Address Standard

Outputs

4 Type A
Counters

1 Type A and
1 Type B

Standard
Outputs

3 Type A
Counters

1 Type A and 1
Type B

%Q 0001

Output 1

Counter 1
Output/PWM/PT1

Output 1

Counter 1
Output/PWM/PT1

Type B Counter
Output

0002

Output 2

Counter 2
Output/PWM/PT2

Output 2

Counter 2
Output/PWM/PT2

Standard Output
2

0003

Output 3

Counter 3
Output/PWM/PT3

Standard Output
3

Output 3

Counter 3
Output/PWM/PT3

Type A Counter
Output

0004

Output 4

Counter 4
Output/PWM/PT4

Type A Counter
Output

Output 4

Standard

Standard Output
4

0005

Output 5

0006

Output 6

0007-0009 Outputs 7-9

0007-0016 Outputs for 23- and 28-point Micro PLCs, Default

first discrete output for 14-pt PLCs (can be
reconfigured).

0017

Default first discrete output for expansion unit
(28/23pt PLCs), can be reconfigured.

0489-0492 Input Direction for Channel 1 to Channel 4

Reserved

0493

Reserved

0494

Start Q1 Pulse Train

0495

Start Q2 Pulse Train

0496

Start Q3 Pulse Train

0497

Clear Strobe bit for HSC 1

0498

Clear Strobe bit for HSC 2

0499

Clear Strobe bit for HSC 3

0500

Clear Strobe bit for HSC 4

Reserved

0501

Reset Preload bit HSC 1

0502

Reset Preload bit HSC 2

0503

Reset Preload bit HSC 3

0504

Reset Preload bit HSC 4

Reserved

0505

Enable Output HSC 1/PTO/PTM

0506

Enable Output HSC 2/PTO/PTM

0507

Enable Output HSC 3/PTO/PTM

0508

Enable Output HSC 4/PTO/PTM

Reserved

0509-510 Not used but unavailable

0511

Start Q4 Pulse Train

Reserved

0512

Clear Error (all counters)

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22.2.3

Reserved Word Memory Locations: %AI

Micro PLCS (14- thru 64-Point)

Nano PLCs (10-Point)

Address

4 Type A Counter or
1 Type A / 1 Type B: 16 Bits

4 Type A Counter 32 Bits
1 Type A / 1 Type B:
32 Bits (Micro-20/-40/-64)

Standard
Outputs

3 Type A
Counters

1 Type A and
1 Type B

%AI

001

Module Status code

002

Counts per timebase HSC 1

003

Counts per timebase HSC 2

004

Counts per timebase HSC 3

005

Counts per timebase HSC 4

006

Accumulator HSC 1 channel 1

Accumulator or Position
Register, channel 1

Accumulator HSC 1

007

Strobe Register HSC 1 channel 2

Strobe Register HSC 1

008

Accumulator HSC 2 channel 3 or
Position Register, channel 1

Strobe Register HSC 1

Accumulator HSC 2

009

Strobe Register HSC 2 channel 4

Strobe Register HSC 2

010

Accumulator HSC 3

Accumulator or Position
Register, channel 2

Accumulator HSC 3

011

Strobe Register HSC 3

012

Accumulator HSC 4

Strobe Register HSC 2

013

Strobe Register HSC 4

014

Not used (set to 0)

015

Not used (set to 0)

016

Analog potentiometer 1

017

Analog potentiometer 2

018

Analog input channel 1

019

Analog input channel 2

020-021 Inputs 1 - 4 from 1st analog

expansion unit

Accumulator or Position
Register, channel 3

022-023

Strobe Register HSC 3

024-025 Inputs 1 - 4 from 2nd analog

expansion unit

Accumulator or Position
Register, channel 4

026-027

Strobe Register HSC 4

028-029 Inputs 1 - 4 from 3rd analog

expansion unit

Inputs 1 - 4 from 1st analog
expansion unit

030-031

032-033 Inputs 1 - 4 from 4th analog

expansion unit

Inputs 1 - 4 from 2nd analog
expansion unit

034-035

036-039 Available references

Inputs 1 - 4 from 3rd analog
expansion unit

040-043

Inputs 1 - 4 from 4th analog
expansion unit

can be reconfigured.

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Micro PLCS (14- thru 64-Point)

Nano PLCs (10-Point)

Address

4 Type A Counter or
1 Type A / 1 Type B: 16 Bits

4 Type A Counter 32 Bits
1 Type A / 1 Type B:
32 Bits (Micro-20/-40/-64)

Standard
Outputs

3 Type A
Counters

1 Type A and
1 Type B

044-128 Available references

22.2.4

Reserved Word Memory Locations: %AQ

Micro PLCS (14- thru 64-Point)

Nano PLCs (10-Point)

Address

4 Type A Counter or
1 Type A / 1 Type B:
16 Bits

4 Type A Counter 32 Bits
1 Type A / 1 Type B:
32 Bits (Micro-20/-40/-64)

Standar
d
Outputs

3 Type A
Counters

1 Type A
and
1 Type B

%AQ

001

Controls the number of input samples for analog
potentiometer input filtering.

Available

002

PWM Frequency Q1

Available PWM Frequency Q1

003

PWM Duty Cycle Q1

Available PWM Duty Cycle Q1

004

PWM Frequency Q2

Available PWM Frequency 2 Available

005

PWM Duty Cycle Q2

Available PWM Duty Cycle 2 Available

006

PWM Frequency Q3

Available PWM Frequency 3 Available

007

PWM Duty Cycle Q3

Available PWM Duty Cycle 3 Available

008

PWM Frequency Q4

Available

009

PWM Duty Cycle Q4

Available

011

Discrete input filtering time value

Available

012

Analog output channel 1

Available

013,014 Outputs 1, 2 for 1st analog expansion unit, can be

reconfigured

Available

015,016 Outputs 1, 2 for 2nd analog expansion unit, can be

reconfigured

Available

017,018 Outputs 1, 2 for 3rd analog expansion unit, can be

reconfigured

Available

019,020 Outputs 1, 2 for 4th analog expansion unit, can be

reconfigured

Available

117-120 Available

Available

121

Frequency of Q4 pulse train

Available

122

Number of pulses to send to Q4 output (0 to 65535)

123

Frequency of Q1 pulse train

Available PT Frequency Q1

124

Number of pulses to send to Q1 output (0 to 65535)

Available Number of Pulses Q1

125

Frequency of Q2 pulse train

Available Frequency 2

Available

126

Number of pulses to send to Q2 output (0 to 65535)

Available Pulses 2

Available

127

Frequency of Q3 pulse train

Available Frequency 3

Available

128

Number of pulses to send to Q3 output (0 to 65535)

Available Pulses 3

Available

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416

22.3

Retentiveness of Data

Data is called “retentive” if it is automatically saved when the PLC is stopped. Retentive data

is also saved when the PLC is power cycled on units that have capacitor or battery-backed
memory. The following data is retentive:

•

Program logic

•

Fault tables and diagnostics

•

Overrides

•

Word data (%R, %AI, %AQ)

•

Bit data (%I, %SC, %G, fault bits and reserved bits)

•

Word data stored in %Q and %M.

•

Data in %Q or %M references that are used as function block outputs or with
retentive coils:

-(M)-

retentive coils

-(/M)-

negated retentive coils

-(SM)-

retentive SET coils

-(RM)-

retentive RESET coils

The last time a %Q or %M reference is used with a coil, the coil type determines whether the
data is retentive or non-retentive. For example, if %Q0001 was last programmed as the
reference of a retentive coil, the %Q0001 data is retentive. However, if %Q0001 was last
programmed on a non-retentive coil, then the %Q0001 data is non-retentive.

•

%Q or %M references that have been made retentive by specifically declaring them
to be retentive. %Q and %M references default to non-retentive.

The following data is non-retentive:

•

%T data

•

%S, %SA, and %SB data (but %SC bit data IS retentive).

•

%Q and %M references that have not been declared to be retentive.

•

%Q and %M references that are used with non-retentive coils:

-( )-

coils

-(/)-

negated coils

-(S)-

SET coils

-(R)-

RESET coils

User Manual

Chapter 22

GFK-1645M

Dec 2019

Program Data and References

417

22.4

System Status References

The Nano/Micro PLC stores status and other system data in predefined references in %S,
%SA, %SB, and %SC memory. Tables on the following pages list all of the System Status
References.

22.4.1

Using the System Status References

System status references can be used as needed in application programs. For easier
programming, each system status reference has a descriptive nickname. For example, the
following function block uses the FST_SCN (first scan) status reference to control power flow
to a Block Clear function.

Figure 237

Other system status reference nicknames include T_10MS, T_100MS, T_SEC, and T_MIN
(see below), FST_SCN, ALW_ON, and ALW_OFF.

22.4.2

Time-Tick References

Time-tick contacts represent specific locations in %S memory. They can be used to provide
regular pulses of power flow to other program functions. The four time-tick contacts have
time durations of 0.01 second, 0.1 second, 1.0 second, and 1 minute.

The state of these contacts does not change during the execution of the sweep. These
contacts provide a pulse having an equal on and off time duration.

The contacts are referenced as T_10MS (0.01 second), T_100MS (0.1 second), T_SEC (1.0
second), and T_MIN (1 minute).

The following timing diagram represents the on/off time duration of these contacts.

Figure 238

EMERSON PACSystems VersaMax MICRO PLC & NANO PLC. USER MANUAL (2019) - page 28