plc structured text

8/10/2019 PLC Structured Text

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PLC-5 Structured TextRelease 1.1

User Manual


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Because of the variety of uses for the products described in this

publication, those responsible for the application and use of this control

equipment must satisfy themselves that all necessary steps have been

taken to assure that each application and use meets all performance and

safety requirements, including any applicable laws, regulations, codes

and standards.

The illustrations, charts, sample programs and layout examples shown in

this guide are intended solely for purposes of example. Since there are

many variables and requirements associated with any particular

installation, Allen-Bradley does not assume responsibility or liability

(to include intellectual property liability) for actual use based upon the

examples shown in this publication.

Allen-Bradley publication SGI-1.1, Safety Guidelines for the Application,

Installation, and Maintenance of Solid State Control(available from your

local Allen-Bradley office), describes some important differences between

solid-state equipment and electromechanical devices that should be taken

into consideration when applying products such as those described in

this publication.

Reproduction of the contents of this copyrighted publication, in whole

or in part, without written permission of Allen-Bradley Company, Inc.,

is prohibited.

Throughout this manual we use notes to make you aware of

safety considerations:

ATTENTION: Identifies information about practices or

circumstances that can lead to personal injury or death, property

damage or economic loss.

Attention statements help you to:

identify a hazard

avoid the hazard

recognize the consequences

Important: Identifies information that is critical for successful application

and understanding of the product.

Important User Information


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Structured Text User Manual

i

Summary of Changes

This release of the publication contains updated information.

For this updated information: See:

corrected the smallest and largest f loating point values chapter 1

rule about using a single % character in a structured text file chapter 1

information about using and exiting iterative loops chapter 2

memory requirements for constructs chapter 2

how to access the database editor and the data monitor fromthe structured text editor

chapter 3

information about accepting structured text edits chapter 3

information about editing structured text files in multipleWindows sessions

chapter 3

clarification about how the PowerText feature intensifiesaddresses with NOT operands

chapter 4

how to toggle between displaying addresses and symbolswhen monitoring structured text

chapter 4

correction to the programming example for creating aconfigurable data monitor with a structured text file

chapter 4

additional programming example for a sort routine appendix A

information about debugging structured text programs appendix A

new appendix that lists the supported processor instructions,syntax, valid operands, and whether an instruction requires afalse-to-true transition before executing

appendix B

new appendix that shows an example of an ASCII structuredtext file that you can import into 6200

appendix C

To help you find new information in this publication, we included change

bars as shown to the right of this paragraph.

Whats New


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PrefaceStructured Text User Manual

i

StructuredText User Manual

6200 Programming SoftwareStructured Text

Your PLC-5programmable controller documentation is organized into

manuals according to the tasks you perform. This organization lets you easily

find the information you want without reading through information that is not

related to your current task.

Figure 1EnhancedPLC-5 Programmable Controller Documentation

Programming

6200-6.4.7

Software Configurationand Maintenance

6200-6.4.6

Configuring processorProcessor/channel status

Defining data table files

Printing reportsClearing faults

Saving/restoring filesCreating/managing files

Creating/editing SFCsImporting/exporting

I/O Configuration

6200-6.4.12

Software

Configuring intelligentI/O modules

6200-6.4.11

ReferenceInstruction Set

Instruction execution,parameters, statusbits and examples

1785 PLC-5Programmable Controllers

Quick Reference

Quick access to switches,status bits, indicators,

1785-7.1

6200-6.4.18

Structured TextUser Manual

Program considerations

Mnemonic explanationsProgram examples

Using PowerTextInstruction parametersand syntax

Creating/editing/documenting ladderlogic programs

instructions, software screens

Installing 6200programming software

1785-6.5.12

Enhanced and EthernetPLC-5 Programmable

Controllers User Manual

Enhanced PLC-5Programmable

Controllers

Ethernet PLC-5

1785-2.38 1785-2.30

Placing system hardwareAddressing I/O andprocessor memoryCommunicating withdevices on a DH+, serial,and Ethernet link

Installation Instructions

Programmable

ControllersInstallation Instructions

Handling the Enhanced

Connecting a remote,extended local, andDH+ link

PLC-5 processorHandling the Enhanced

Connecting a remote,extended local, andDH+ link

PLC-5 processor

For more information about PLC-5 programmablecontrollers or these publications, contact yourlocal sales office, distributor, or system integrator.

HARDWARE SOFTWARE

Youare here

How to Use YourDocumentation


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Structured Text User ManualPreface

ii


To use 6200 programming software:

If you are a new user of an enhanced PLC-5 processor, use the Enhanced

PLC-5 Programmable Controllers Installation Instructions, publication

1785-2.38, or the Ethernet PLC-5 Programmable Controllers Installation

Instructions, publication 1785-2.30, to make sure your PLC-5 system is

correctly installed. Then see the Enhanced and Ethernet PLC-5

Programmable Controllers User Manual, publication 1785-6.5.12, for

programming guidelines.

After your system is up and running, use the Quick Reference manual,

publication 1785-7.1, for help in maintaining your system.

If you are already familiar with 6200 programming software, you might only

need the Instruction Set Reference manual, publication 6200-6.4.11, or the

Structured Text User Manual, publication 6200-6.4.18.

This manual uses the following conventions to describe how to

enter information:

Unless otherwise stated:

References to: Include these Allen-Bradley Processors:

Classic PLC-5 processors PLC-5/10, -5/12, -5/15, -5/25, and -5/VMEprocessors.

Enhanced PLC-5 processors PLC-5/11, -5/20, -5/30, -5/40, -5/40L, -5/60

,

-5/60L,and -5/80processors.

Important: Unless otherwise specified, Enhanced PLC-5processors include Ethernet PLC-5 and VME PLC-5 processors.

Ethernet PLC-5 processors PLC-5/20E, -5/40E, and -5/80Eprocessors.

VME PLC-5 processors PLC-5/V30, -5/V40, -5/V40L, and -5/V80 processors. See thePLC-5/VME VMEbus Programmable Controllers User Manual,publication 1785-6.5.9, for more information.

Where to Start

Conventions


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Structured Text User ManualPreface

iii


Pictures of keys and/or screens represent actual keys that you press or screens

that you see. For example, in the procedure for creating a structured text file,

you see:

+= PROGRAM DIRECTORY FOR PROCESSOR: EXPSFC ======================[ OFFLINE ]===+

| File Name Type Size(words) |

||

| 0 system 10 |

| 1 function chart 69 |

| 2 undefined 6 |

| 3 ladder 7 |

| 4 ladder 7 |

| 5 ladder 7 |

| 6 ladder 7 |

| 7 ladder 7 |

| 8 ladder 7 |

| 9 ladder 7 |

| 10 ladder 7 |

| 11 ladder 7 |

| 12 ladder 7 |

| |+==============================================================================+

Press a function key.

>

Rem Prog PLC5/40 Series C Revision C 5/40 File EXPSFC

Create Create Create

Lad Fl SFC Fl STxt Fl

F6 F7 F8

F1

Proc Functions

ProgramDirectory

Press1

2

3

Enter the number of the file to create.

Press Esc to return to ProgramDirectory

F8

Create STxt Fl

to create a structured text file.

F6

Create File

What the procedure shows is that from the program directory, press [F1]and

then [F6]to display this screen. Then press [F8]to create a structured text

file and enter the file number. Press [Esc]to return to the program directory.

Words in square brackets represent actual keys that you press. For example:

[Enter] or[F1] Online Programming/Documentation

Words that describe information that you have to provide are shown in

italics. For example, if you have to type a file name, this is shown as:

filename

Messages and prompts that the terminal displays are shown as:

Press a function key


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Structured Text User ManualTable of Contents

iv


Chapter1Chapter Objectives 1-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Using Structured Text 1-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Installing the Software 1-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Writing Structured Text 1-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Rules for Writing Structured Text 1-6. . . . . . . . . . . . . . . . . . . . . . . . . . .


Variable Assignment (:=) 2-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Non-Retentive Bit Assignments (:=) 2-2. . . . . . . . . . . . . . . . . . . . . . . . .

Retentive Bit Assignments (RETAIN) 2-3. . . . . . . . . . . . . . . . . . . . . . .

IF-ELSIF-ELSE 2-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CASE 2-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .FOR 2-6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

WHILE 2-7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

REPEAT 2-8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

EXIT 2-9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

;; 2-10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Ladder Functions 2-10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Memory Requirements 2-12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chapter3

Chapter Objectives 3-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Creating a Structured Text File 3-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Configuring the Structured Text Editor 3-2. . . . . . . . . . . . . . . . . . . . . . .

Defining Addresses and Symbols 3-3. . . . . . . . . . . . . . . . . . . . . . . . . . .

Entering Structured Text 3-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Editing Structured Text 3-7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Creating Documentation Reports 3-10. . . . . . . . . . . . . . . . . . . . . . . . . . .


Using PowerText 4-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Creating a Configurable Data Monitor 4-4. . . . . . . . . . . . . . . . . . . . . . .

Writing Structured Text

Structured Text Constructs

Using the Structured

Text Editor

Monitoring Structured Text


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Structured Text User ManualTable of Contents

v


Appendix AAppendix Objectives A-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Programming a Free Running Timer A-1. . . . . . . . . . . . . . . . . . . . . . . . .

Programming a Sort Routine A-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Debugging Programs A-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Appendix BInstruction Operands and Valid Data Types B-1. . . . . . . . . . . . . . . . . . .

Appendix CASCII Structured Text Processor Memory File Example C-1. . . . . . . . .

Structured Text Syntax for Above ASCII File C-9. . . . . . . . . . . . . . . . .

ApplicationExample

Instruction Reference

ASCII Structured TextProgramming Example


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Important: Remove any previous versions of thesoftware before installing the new version. Forinformation about removing the software, seethe PLC-5 Configuration and Maintenancemanual, publication 6200-6.4.6.

a:is the drive where you insert the disk.

c:is any destination hard-disk for theprogramming software.

Chapter

1

1-1



Use this chapter to learn what structured text is and how you can use it as

an alternative to or in conjunction with ladder logic or Sequential Function

Charts (SFCs).

Structured text is an English-like set of instructions and mnemonics that

you can use to perform most of the same tasks that you already perform

with ladder logic. The structured text language resembles BASIC and isbased on the International Electrotechnical Commission (IEC) 1131-3

standard for programmable controller software.

Structured text supports complex expressions and both logical and

symbolic addressing. Use structured text or ladder logic to program

MCPs, subroutines, or actions and/or transitions in SFCs, depending on

which type of programming best suits your application and how much

memory you have available.

Structured text is only supported on enhanced PLC-5 series C, revision C

and later processors. To use release 1.1 of structured text, you must install

release 5.0 of 6200 PLC-5 programming software (catalog number62xx-PLC5) and theninstall release 1.1 of PLC-5 structured text (catalog

number 6203-ST5).

Important: Install the 6200 programming software first; then install the

structured text disk last. For information on installing this disk, see the

next section. For more information, see the PLC-5 Configuration and

Maintenance manual, publication 6200-6.4.6.

1. Turn on the computer.

2. When the DOS prompt appears, insert the structured text disk into the

disk drive. Type:

A: Return

INSTALL C: Return

ChapterObjectives

Using Structured Text

Installing the Software


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Writing Structured TextChapter 1

1-2


You see:

******

**

***********************************************************************

Press Any Key to Start Installation

******

**

Allen-Bradley Company, Inc., Copyright 1995, All rights reserved.

Allen-Bradley Company, Inc. grants you a license to installand use this software on a single processing unit. You are not licensed toinstall the software on more than one processing unit or to distribute it inany way. Support and updates will be provided to registered customersonly. To register your software, return the enclosed registration card assoon as possible.

WARNINGTHIS SOFTWARE IS PROTECTED UNDER THE COPYRIGHT LAWS OF THE UNITED STATES.UNAUTHORIZED REPRODUCTION OF COPYRIGHTED SOFTWARE VIOLATES U.S. COPYRIGHTLAWS. CRIMINAL PENALTIESMAY INCLUDE FINES OR IMPRISONMENT.

******************************************************************

******************************************************************

Contents: PLC-5 Prog Structured Text Programming OptionCatalog Number: 6203-ST5Part Number: XXXXXX-XXRelease Number: 1.1 Quantity 1 Disk

Press any key

Press

Contents: PLC-5 Prog Structured Text Programming OptionCatalog Number: 6203-ST5Part Number: XXXXXX-XXRelease Number: 2.0 Quantity 1 Disk

Product Registration Information

Company Name: Address: :Serial Number:

Instructions

Enter your company name and address.You can find the serial number on the frontof the product box. Format is AA0AA0AA.

Enter product registration info and press F9

When you are finished, press F9

1

2

3

4

Return

Company Name: Allen-Bradley Address: 747 Alpha Drive : Highland Hts OH 44143Serial Number:: XXOXXOXX

Press ENTER to continue with the installation


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1-3


After you enter the product registration, you see:

Contents: PLC-5Prog Structured Text Programming OptionCatalog Number: 6203-ST5Part Number: XXXXXXXXXRelease Number: 1.1 Quantity x Disks

Instructions

The File Copy portion of Install is Complete: Press ENTER

Status98% Complete

0% 25% 50% 75% 100%

CopyUPD.EXE to C:\IPDS\UPD.EXE

Enter

After structured text is installed,press

The percent completion baradvances as the installationprogresses.

The file names display as theyare copied to your hard disk.

5

To write structured text, you need to understand the following definitions:

a structured text command. Depending on its function, a construct may

require one or more lines. For example,

REPEAT

N7:0 := N7:0 + 1;

UNTIL N7:0 > (N7:10 / 10)

END_REPEAT;

any standard PLC-5 operand address. An operand can also be a symbol.

For example, N7:0.

any standard PLC-5 bit operand address. For example, B3/0.

a constant number, integer, or floating point, appearing directly in the

expression. Valid integers must fall within the range of -32768 to +32767.

The largest floating point magnitude is 3.402823e+38. The smallest

floating point magnitude is 5.877472e-39.

If an integer value falls outside of these ranges, it is truncated to 16 bits.

No error is flagged.


construct

operand

bit operand

immediate


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1-4


a sequence of operands and/or immediates separated by math operators or

acted on by a math function. See the following list of operators.

Operator: Function: Operator: Function:

+ add LN natural log

subtract LOG log to the base 10

/ divide DEG degree (convert radians to degrees)

* multiply RAD radian (convert degrees to radians)

modulo (MOD) returns the remainder of an integer divide SIN sine

SQR square root COS cosine

FRD convert from BCD TAN tangent

TOD convert to BCD ASN arc sine

NOT logical NOT ACS arc cosine

NEG negate ATN arc tangent

a sequence of 2 operands, immediates, and/or math expressions separated

by one of the following operators.

Operator: Function:

< less than

> greater than

= equal

= greater than or equal

not equal

any valid ladder input instruction (excluding LBL and SBR) or compare

expression. You can examine the state of a bit by specifying the address of

the bit you want (i.e. I:0/0). This operand or expression is true if the

specified bit is a logical 1. To invert the logic (the operand or expression is

true if the bit is a logical 0) precede the bit address with a ! (i.e. !I:0/0).

For example, XIC (I:0/0).

math expression

compare expression

input instruction


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1-5


a sequence of input instructions separated by boolean AND, OR, or XOR.

(You can only use XOR with bit operands and compare expressions. You

can implement a ladder function extension by assigning the logic state to a

bit and using the bit address in the XOR expression).

Precedence in an expression is evaluated according to the following list

(from highest to lowest priority):

1. !(bit inversion)

2. parentheses

3. exponentiation (** or XPY())

4. SQR(), TOD(), FRD(), NOT(), NEG(), LN(), LOG(), DEG(), RAD(),

SIN(), COS(), TAN(), ASN(), ACS(), ATN()

5. *, / , MOD

6. +,

7. logical AND (whole word value)

8. logical XOR (whole word value)

9. logical OR (whole word value)

10. =, , >,


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1-6


Follow these rules when writing structured text:

Important: Do not insert a single % character in a structured text file.

When you accept the edits, the software deletes the rest of the file that

follows the % character because the software assumes the remainder of the

file is a comment.

Keywords, operators, and operands MUSTbe separated by whitespace

For example:

The characterindicates where you should enter a space.

N7:0:=10;

N7:0:=N7:10;

N7:0:=R6:0.LEN;

F8:0:=((N7:1*3.14)+(N7:3/N7:4));

Each statement must end with a semicolon. See chapter 3.

String data types are not supported by the PowerTextfeature.

For example, entering (ST15:0 := ST15:1)is not supported. String

data values in length (but not position) are supported. Therefore,

(ST15:0.LEN := N7:0)is supported.

Structured text is not case sensitive (i.e. WHILE, While, and whileare

all equivalent).

When writing or entering a program, you can use a semicolon anywhere(see important note below) you would use a colon. For example, you

can enter N7:0 := N7:1;as N7;0 ;= N7;1 ;. But the converse is not true -

N7:1 := N7:1:is incorrect, because each statement must end with

a semicolon.

Important: The only exception to the above rule is in the case specifier.

For example:

CASE N7:0 Of

1:

(1;is invalid.)

Important: Due to the expansion of the display by the PowerText

feature, there is a 16 line (1 line = 80 characters) limit in Run mode for a

continuous line of structured text. Although these expressions can span

multiple lines, they must not exceed 16 lines in Run mode. Note that a

construct that takes 16 lines in Program mode may take more than 16

lines in Run mode. See the table describing field widths on page 4-5.

Rules for WritingStructured Text


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1-7


When writing or entering a program, the following are equivalent

and interchangeable:

This Is: Equivalent and Interchangeable With:

{ DO, THEN, OF

ELSIF ELSE_IF, ELSEIF

AND (boolean) &&, &

OR (boolean) ||

} (no semicolonrequired)

END_FOR;, END_CASE;, ENDIF;,ENDWHILE;, ENDREPEAT;,END_WHILE;, END_REPEAT;,ENDFOR;, ENDCASE;, END_IF;

Important: Although you can use braces ({}) when writing or entering

a program, the syntax of structured text is different than that used in the

standard C programming language. In the following comparison, the

original program version does not have matching pairs of braces. In

structured text, this is correct syntax.

Standard Format: Original Program:

IF(N7:0 = 1) THEN

Structured Text

ELSIF (N7:3 = 27) THEN

Structured Text

ELSE

Structured Text

ENDIF ;

(Code to do one of three things usingstandard nomenclature.)

IF(N7:0 = 1) {

Structured Text

else_if (N7:3 = 27) {

Structured Text

ELSE

Structured Text

}

(Code to do one of three things using { }nomenclature.)

The following words are reserved and you should not use them

as symbols:

- any ladder instruction mnemonic (i.e. LOG, DEG)

- any structured text keyword or equivalent (i.e. CASE, FOR)

- START, DATA, PROJECT, SFC, SFC2, LADDER, I/O, ASCII,

CAR, FORCE, PLC2, CONFIG, INC, ALL, YES, NO,

STRUCTURED TEXT


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1-8


The structured text compiler handles spaces around constructs as

described in the example below.

Construct Construct

End

Blank Line 1

Blank Line 2

XX := YY;

Blank Line 3

XX := YY;

Blank Line 4

no line

no line

The compiler inserts blank lines before and after thefirst level of the following constructs (not nestedconstructs): IF, ELSEIF, ELSE, CASE, FOR, WHILE,REPEAT. See Blank Line 1 and Blank Line 2 and thearrows indicating no lines between nested constructs.

The compiler removes the blank lines you insert inplaces other than before and after the first level of theabove constructs, i.e. before or after a variableassignment, before or after a ladder function. SeeBlank Line 3 and Blank Line 4. If you insert theselines, the compiler removes them.

End Construct


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Chapter

2

2-1


Structured Text Constructs

After you prepare your design specification and, if applicable, enter your

sequential function chart (SFC), you are ready to enter the structured text

that runs your application. Use this chapter to learn about the structured

text constructsthat you can use. The following table lists page references

for each construct.

If You Want to: Use this: See Page:

assign an integer or floating point valueto a data table location

variable assignment 2-2

make bit assignments (non-retentive) non-retentive bitassignment

2-2

make bit assignments (retentive) retentive bitassignment

2-3

conditionally execute a section of code IF-ELSIF-ELSE 2-4

conditionally execute a section of codebased on the value of a math expressionor operand

CASE 2-5

repeat a section of code a specifiednumber of times

FOR 2-6

repeat a section of code as long as an

input condition is true

WHILE 2-7

repeat a section of code until an inputcondition becomes true

REPEAT 2-8

exit an iterative command (FOR, WHILE,or REPEAT) before it reaches the normaltermination condition

EXIT 2-9

perform no function, treated aswhitespace

;; 2-10

call PLC-5 input instruction or outputinstruction as functions

ladder functions 2-10

The last section in this chapter provides guidelines for the memory

requirements for the constructs.

ATTENTION: The examples throughout this publication are

meant to help you create your own structured text programs.

They may need modification to work correctly for

your application.

ChapterObjectives


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Structured Text ConstructsChapter 2

2-2


Use this construct to assign an integer or floating point value to a data

table location. See the following formats and examples.

Format: Examples:

operand := immediate ; N7:0:= 10;

operand := operand ; N7:0 := N7:10;N7:0 := R6:0.LEN

operand := math expression ;

: := : . ;

F8:0 := ((N7:1 * 3.14) + (N7:3 / N7:4));

Variable assignments are synonymous with MOV instructions. The source

of the MOV instruction corresponds to the right side of the variable

assignment and the destination of the MOV instruction corresponds to the

left side of the assignment.

MOV

Source

Destination

N30:0

N30:1

N30:1 := N30:0

Use this construct to make binary assignments to a storage bit. These bit

addresses are non-retentive (they are cleared to 0 when the processor mode

changes from Program to Run or when an SFC step with the structured text

file as an action is postscanned). See the following formats and examples:

Format: Examples:

bit_operand := 0;

bit_operand := 1;

bit_operand := bit_operand;

bit_operand := compare_expr;

B3/0:= 0;

N7:0/0 := 1;

O:0/0 := N7:0/0;

B3:0/11 := N7:1 (N7:10 / 10)

END_REPEAT;

N7:0 increments by 1

until N7:0 is greater than N7:10divided by 10

Important: Do not use I/O addresses in iterative constructs as test values

because they will not be updated by real I/O. The PLC-5 processor is

processing the loop and it cannot continue to the end of the program where

it performs housekeeping and updates remote I/O.

REPEAT

code inside the loop


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2-9


In a running processor, all structured text constructs complete before the

program scan continues. If the REPEAT loop takes longer to complete

than the watchdog setpoint, the watchdog timer times out. This is a major

fault that shuts down the processor.

Important: When the processor runs a REPEAT loop, all other processing

is put on hold, like checking for a change in the processor keyswitch or a

change in I/O status. The following examples show how to exit a REPEAT

loop. You can also use these methods with FOR and WHILE constructs.

Method: Examples:

IIN instruction REPEAT N7:0 := N7:0 +1;

IIN (000);

IF (I:000/07) THEN

EXIT; END_IF;

UNTIL (N7:0 > 25)

END_REPEAT;

EXIT construct REPEAT N7:0 := N7:0 +1;

IF (B3:0/0 = 1 ) THEN

EXIT;

END_IF;

UNTIL (N7:0 > (N7:10 /10)

END_REPEAT;

Use this construct to exit an iterative construct (FOR, WHILE, orREPEAT) before the processor reaches the normal termination condition.

The processor continues execution of the program at the line following

the end of the current iterative construct. See the following formats

and examples.

Format: Examples:

EXIT; FORN7:0 := 0 TO 10 DO WHILE N7:1/0 DO

N7:10:=(N7:10 + 10) / (SIN(F8:0));

IF N7:5 < 4 THEN

EXIT;

END_IF;

END_WHILE; N7:11 := N7:12 + 1;

END_FOR;

exit the WHILE loop early

execution continues here

EXIT


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2-10


This construct performs no function and is provided for IEC standard

1131-3 compatibility. The processor treats it in the same way as

whitespace to make programs more readable. See the following example.

Format: Examples:

;; IFN7:0/0 THEN;;

ELSE

N7:2 := N7:5 +10;

END_IF;

no effect on program scantime

Use this construct to call PLC-5 input or output instructions as functions.

Enter the instructions as you would in an exported processor memory file

(ASCII format) with the following exceptions: enclose the operands within parentheses

separate the operands by commas

omit the SOR and EOR statements

For a complete list of supported instructions, operands, and valid data

types, see appendix B.

You can use any ladder instruction as a ladder function, with the following

exceptions. You cannot use: LBL, JMP, END, MCR, FOR, BRK, NXT,

MSG, SDS, DFA, AND, OR, XOR, and TND. See the following formats

and examples.

Format: Examples:

output instruction (operand a, operand b,...);

input expression output instruction (operand list);

FAL(R6:0,10,0,ALL,#N7:0,#N7:1+#N7:2);

DTR(N7:0,N7:1, N7:2) OTE O:0/3

FAL(R6:0,10,0,ALL,#N7:0,#N7:1+#N7:2);

N7:0 > N7:1 FAL(R6:0,10,0,ALL,#N7:0,#N7:1+#N7:2);

Some input instructions require output instructions for correct syntax (see

the DTR example above). Appendix B identifies which instructions

require output instructions.

In general, enter ladder functions exactly as they are displayed in theladder editor. You must specify all fields, even those that are display-only

fields in the ladder editor. Any field that accepts a word (i.e. Yes or

No in a block transfer) must be fully specified (Y or N is invalid.)

;;

Ladder Functions


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2-11


The JSR instruction is an exception, and must be entered as follows:

JSR(SBR_file_number, number_of_input_parameters, parameter_list);

For example, enter a JSR to execute subroutine file number 3, with no parameters as:JSR(3,0);

Enter a JSR to execute subroutine file number 7, with 2 input parameters and 3 return parameters as:JSR(7,2, N7:0, N7:1, N7:2, N7:3, N7:4);

Although you cannot use certain ladder instructions in a structured text

program (see above), you can, however, access sub-element data associated

with these instructions. For example, you could include the following in a

structured text program:

IF MG10:1.EN THEN

...MG10:1.DLEN := 4;

END_IF;

ATTENTION: Structured text does not prevent you from

assigning invalid values to sub-elements. Doing so could result

in improper machine operation, damage to equipment, and/or

injury to personnel. It is your responsibility to check the

validity of all assignments.

Structured text has equivalents to OTL, OTU, OTE, CPT, FOR, NXT,

BRK, AND, and OR instructions. See the following table for pagereferences for these functions. Structured text has no direct equivalent to

the JMP instruction. Use the CASE and WHILE constructs instead.

For an Equivalent tothese Constructs:

See Page and Section:

OTE 2-2 (Non-Retentive Bit Assignments)

OTL, OTU 2-3 (Retentive Bit Assignments)

CPT 2-2 (Variable Assignment)

FOR, NXT, BRK 2-6 (FOR)

AND, OR 2-2 (Variable Assignment)

Important: OTL, OTU, OTE, and CPT are valid output instructions instructured text. However, they will be displayed as their structured text

counterparts after you accept the logic.

Important: In ladder programming, the SBR instruction is an input

instruction. This instruction must be the first instruction in a program file

and must be followed by an output instruction. In structured text

programming, however, no output instruction is required, but the SBR

instruction still must be the first instruction in the program file.


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2-12


Important: Be careful when using ladder functions inside of conditional

constructs. Some ladder functions are transitional and do not operate

properly if not scanned with a false rung status. For example, a false IF

skips over the code inside the IF, whereas a false logic rung executes the

output instruction for a false case. (An ASCII Write instruction, AWT,

needs a false scan after the instruction executes to correctly reset.)

Note that if you test control bits of timers, counters, or instructions that use

control file limits, those instructions must be scanned in the loop or they

will not be updated.

Each structured text file uses 7 words for overhead.

The ladder-function constructs take the same amount of memory as theirladder counterparts. The complex constructs have the following memory

requirements (not including the code section):

Construct: Memory Requirement:

IF input expressions + 9 words

ELSIF input expressions + 9 words

ELSE 2 words

END_IF 2 words

END_FOR 2 words

END_WHILE 2 wordsEND_REPEAT 2 words

END_CASE 2 words

WHILE input expressions + 16 words

REPEAT input expressions + 15 words

EXIT 1 word

EMPTY 0 words

CASE expressions = 14 words

case item 10 to 12 words

discrete (3 to 6 words) * number of items

range 6 to 12 words

Memory Requirements


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Chapter

3

3-1


Using the Structured Text Editor

This chapter explains how to use the structured text editor. Use the

following table to find specific topics.

For this Topic: See Page:

Creating a structured text file 3-1

Configuring the SFC editor forstructured text

3-2

Entering structured text 3-5

Editing structured text 3-7

Creating documentation reports 3-10

Important: If you create a structured text program file, you can only

monitor or restore that file with programming software that supports

structured text.

To create a structured text file, follow the steps on the left:

+= PROGRAM DIRECTORY FOR PROCESSOR: EXPSFC ======================[ OFFLINE ]===+

| File Name Type Size(words) |||

| 0 system 10 |

| 1 function chart 69 |

| 2 undefined 6 |

| 3 ladder 7 |

| 4 ladder 7 |

| 5 ladder 7 |

| 6 ladder 7 |

| 7 ladder 7 |

| 8 ladder 7 |

| 9 ladder 7 |

| 10 ladder 7 |

| 11 ladder 7 |

| 12 ladder 7 |

| |

+==============================================================================+


>

Rem Prog PLC5/40 Series C Revision C 5/40 File EXPSFC

Create Create Create

Lad Fl SFC Fl STxt Fl

F6 F7 F8

F1

Proc Functions

Program

Directory

Press1

2

3

Enter the number of the file to create.

Press Esc to return to ProgramDirectory

F8

Create STxt Fl

to create a structured text file.

F6

Create File

ChapterObjectives

Creating a StructuredText File


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Using the Structured Text EditorChapter 3

3-2


After you create the file, you can enter your structured text. Follow the

steps on the left:

Empty Structured Text File

Press a function key, or use cursor keys to scroll structured text.

MONITOR 11 >

Rem Prog Forces: None Edits: None 5/40 File RUNBATCH

Change Exit Edit Data Edit

Mode DBASE Monitor

F1 F3 F5 F8 F10

cursor tostructured text file

ProgramDirectory

F8

Monitor File

You can configure the structured text editor to display addresses or

symbols. For structured text in MCPs and/or subroutines, this is the only

display characteristic that you can configure. If you are using structured

text in an SFC, you can also adjust the action and/or condition field size

and configure the editor to show either the first line of the structured text

file or the structured text file number in the Action Condition window. To

configure the structured text editor, follow the steps on the left:

SFCMain Menu

F7

GeneralUtility

F2

Configure Display

F8

Act/CndWindow

+= Action/Condition Window Configuration ======================================+

| 10 50 |

| Action/Condition Comment |

| .......... .................................................. |

| |

| F3 Address Display: Suppress Symbol F4 Act/Cnd Dsp: Show Structured Text |

+==============================================================================+

START

+++

+++

END

Press a function key or user left/right arrow keys to configure window.

MONITOR 1:(0,0) >

Rem Prog SFCFrc:Disabled PLC5/40 Ser C Rev C 5/40 File LIMIT

Act/Cnd Comment Address Act/Cnd

Field Field Display Display

F1 F2 F3 F4

Configuring the StructuredText Editor


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3-3


To: Press this Key:

Specify the action/condition field size for the

action/condition window (0-60 characters) byentering it on the command line or using theleft/right arrow keys

[F1] - Act/Cond Fld

Adjusting the Action/Condition field automaticallyadjusts the Comment field size.

Specify the comment field size for theaction/condition window (0-60 characters) byentering it on the command line or using theleft/right arrow keys

[F2] - Comment Field

Adjusting the Comment field automatically adjuststhe Action/Condition field size.

Display address symbols [F3] - Address Display: Display/Suppress Symbol

Suppress address symbolsThis key toggles between displaying or suppressingaddress symbols. The default is to display symbols.

Display the f irst line of structured text [F4] - Act/Cnd Display

This key toggles between displaying the first line ofDisplay the structured text file number

Thi y togg b tw n di p ying th fir t in ofstructured text and displaying the structured text filenumber in the Action/Condition window.

Return to the Display Configuration window. [Esc]

Any addresses and symbols that you want to use in your structured text

files must be assigned before you edit the file. You cannot save a

structured text file that references any addresses or symbols that do not

exist in the database.

You can access the documentation database and the data table monitor

through the structured text editor. You must still define the symbols you

need prior to editing a structured text file. To access the documentation

database or the data table monitor, follow these steps:

DefiningAddressesand Symbols


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3-4


6200Main Menu

F8

Cursor to astructured text file orenter file number

Monitor File

F5

EditDBASE

ProgramDirectory

F1

Online Prog

F3

Offline Prog

or

6200Main Menu

F8


Monitor File

ProgramDirectory

F1

Online Prog

F3

Offline Prog

or

To access the documentation database: To access the data table monitor:

F8

DataMonitor

For more information about using the documentation database, see the

PLC-5 Programming Manual, publication 6200-6.4.7. For more

information about using the data monitor, see the PLC-5 Configuration and

Maintenance Manual, publication 6200-6.4.6.


33/75


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3-6


To enter structured text as a step action or transition condition in an SFC,

follow the steps on the left:

Rem Prog SFCFrc:Disabled PLC-5/40 Ser C Rev C 5/40 Addr 43 DRILL1

Select Edit Copy Remove

File Text Cond Cond

F1 F2 F3 F6

Rem Prog SFCFrc:Disabled PLC-5/40 Ser C Rev C 5/40 Addr 43 DRILL1

Select Edit Append Insert Remove

File Text Action Action Action

F1 F2 F3 F4 F6

Step Trans Step Step Trans

Actions * Timer Name Name

F1 F2 F4 F8 F9

START

+++

+=====+=====+

# MIXER #

+=====+=====+

+

|

|

+++

Press a function key.EDIT 2:(0,0) >

Rem Prog SFCFrc:Disabled PLC5/40 Ser C Rev C 5/40 Addr 43 DRILL1

+= Action Display for Step: MIXER==============================================+

| ActionName QL Action Comment |

++

| ValveChk N 2 (ladder) |

| |

| |

| |

+==============================================================================+

SFCEdit Selections

F10

Edit

SFCMain Menu

F3

Append

Step/Trn orF4

Insert

Step/Trn

Choose or create a structured text file, then cursor to

the Condition Text field and then press

Press the appropriate function key to chooseto create an action or a transition. See below.

Choose or create a structured text file, then cursor to

the Action Text field and then press

If you press F1

StepActions

a

b If you press F2 Trans

F2

Edit Text

F2

Edit Text


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3-7


The editing keys for a structured text file used within an SFC (as an action

or transition) and a structured text file used as an MCP or subroutine are

identical, but the ways to get to the editor are different. To edit structured

text, either in an SFC or as an MCP or subroutine, follow the steps on

the left:

Important: You must be offline or in Program or Remote Program mode

to edit structured text. If you change the processor mode from Program or

Remote Program, all of your edits are lost. The system displays an error

message Processor has changed to Run or Test mode, edit

aborted. The system returns to the SFC main menu (if you are using an

SFC) or the Structured Text View screen (if you are entering structured text

as an MCP or subroutine).

IF (LIMIT_SW1 AND BOXPRESENT) THEN

GATE1 := OPEN;

GATE2 := CLOSE;

ELSIF ((LIMIT_SW2 OR (WEIGHT SETPOINT))) THEN

GATE1 := CLOSE;

GATE2 := CLOSE;

ELSIF (LIMIT_SW3 XOR LIMIT_SW4) THEN

GATE1 := CLOSE;

GATE2 := CLOSE;

ELSE

GATE1 := OPEN;

GATE2 := CLOSE;

END_IF;

Press a function key or enter the structured text.

MONITOR 2 >

Rem Prog Mode:Insert WrapOn Left Col:1 Line:1 5/40 File ST

Delete Undel Delete Undel Delete Undel Advancd Accept

ST File ST File Line Line Word Word Editing ST Edit

F1 F2 F3 F4 F5 F6 F7 F8

Use these editing keys to edit the structured text. For moreinformation on how the editor works, see chapter 17 in thePLC-5 Programming manual, 6200-6.4.7.

SFCEdit Selections

F10

Edit

SFCMain Menu

F5

F1

Step Actions

F2

Edit Text

Ladder EditorMain Menu

F8


Monitor File

F10

Edit

Within an SFC

or F2

Trans

Modify Stp/Trn

Cursor to the Action orCondition Text field

SFCMain Menu

F1

Online Prog

F3

Offline Prog

or

MCP or Subroutine

F4

Prog Dir

Editing Structured Text


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3-8


When you load a structured text program into a processor, the processor

converts the program to IEC standard 1131-3 format. Therefore, if you

monitor or save a program, it is converted to standard format, regardless of

the format in which you wrote it. (For example, if you used semicolons in

place of colons in your program, the semicolons are replaced by colons

when you load the program into the processor.) If you want to keep the

program as you originally entered it, save the original program as a paste

file using the Advanced Editing cut, copy, and paste features.

Accepting Edits

When you finishing entering or editing structured text, press F8 Accept

Edits to accept the edits. The software checks the edits to make sure the

syntax is correct before saving the file. If there is an error in the structuredtext, the software displays an error message explaining the error. You must

correct the error before you can accept edits again.

If there are syntax errors and you want to temporarily save the incorrect

structured text file, use the advanced editing functions to copy the file to a

disk file. You can then later paste the file into an empty structured text file

and correct the syntax errors. Follow the steps below.

Move the cursor to thebeginning of the areayou want to save.

ST Editor

F7

Advanced Editing

F1

Select

Move the cursor to theend of the area youwant to save.

To select the structuredtext to save to disk file:

ST Editor

F2

Cut

F7

Copy to Disk

To copy the selected structuredtext to disk file:

with selected texthighlighted

TIP


37/75


3-9


Important: If you are editing online in Program or Remote Program

mode, do not type ahead after pressing F8 Accept Edits. Wait until the

software completes accepting the edits. The software takes awhile toaccept your edits because it checks all the syntax. If you type ahead, such

as the key sequence for changing to Run mode, the software uses these

keystrokes and deletes the current structured text file after accepting

the edits.

If you do type ahead and the software deletes your structured text file, you

can undelete the file. Do not return to the program directory. Instead,

return to the structured text editor and press F2 Undelete ST File.

Editing Structured Text In Windows

When using multiple sessions, if you edit a structured text file while

displaying the same file in another session, the edit does not appear in the

second session.

Editing Structured Text as an ASCII File

You can create a structured text paste file with most word processors. Save

the file as ASCII or text only in the \IPDS\ARCH\PLC5 directory, with a

.STX extension. You can then paste the file using the advanced editing

paste from disk function.

You can also create an entire processor memory file as an ASCII file and

import that file into 6200. Appendix C shows an example of a processor

memory file complete with data table values.


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3-10


PLC-5 programming software generates and prints reports about

your programs. One of these reports is the Structured Text Listing.

The Structured Text Listing lets you see a printed copy of your structured

text program. To generate a Structured Text Listing, follow the steps on

the left:

F3

F8

Reports

6200Main Menu

selectStructured TextListingas the report togenerate by cursoring to it andpressing

F3

CreateOffline

Select the range of filesto include in the report.

or F1

Create Online

currentprocessormemoryfile

Toggle Report

F5

Report Options

F1

Create Reports

+========================= PLC5 PROGRAMMING SOFTWARE =========================+

| += Offline ======= LIMIT=====+

| A 6200 Series Software Pr| SFC Listing |

| | SFC Cross Reference |

| Copyright 1986, 1995, AllenBradle *| Structured Text Listing |

| All Rights Reserved | Ladder Program Listing |

| | Program Cross Reference |

| Release 5.0 | Program Directory |

| += Structured Text Listing =========+ | Memory Map |

| This so| | | Processor Status |

| | Starting File 1 | | I/O Status |

| | Ending File 999 | | Data Tables |

| | | | Force Status |

| | Address Display SYMBOL | | Symbol Table || | | | Unused Addresses |

| | | | Memory Usage |

| | | | Privilege Classes |

+===========+===================================+=+============================+


Create Select Toggle Reset Report General Define Title Save

Reports All Report Reports Options Options Dir Config

F1 F2 F3 F4 F5 F6 F7 F8 F9

Creating DocumentationReports


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3-11


The status screen (shown below) advises you of the progress of

the report.

+========================================+

| ALLENBRADLEY COMPANY |

| 6200 SERIES SOFTWARE |

| PLC5 DOCUMENTATION SOFTWARE |

+========================================+

Proc File: LIMIT Report: Structured Text Listing

Output: LIMIT.TXR Config: Files 1 999

Phase: GENERATE ST. TXT. LISTING Status: File: 2

+==============================================================================+

|** OPEN PROCESSOR MEMORY FILE ** |

|** GENERATE STRUCTURED TEXT LISTING REPORT ** |

|** GENERATE LISTING FOR FILE 2 ** |

| |

| |

| |

| |

| |

| |+==============================================================================+

Press F3 to abort

Abort

Utility

F3

You can abort this utility with F3

AbortUtility

For more information about reports, including how to print a report, see the

PLC-5 Configuration and Maintenance Manual, publication 6200-6.4.6.

Tue Jan 3, 1995 Page 1

Structured Text Listing Report PLC5/40 Addr 68 File 2

R6:6.DN AND ONS (B3/4) MOV (ST15:3.LEN, N17:85);

A structured text listing looks similar to the above screen. The structured textlisting file has a .TXR extension and resides in the IPDS\TEXT\PLC5 directory.

F8

Reports

6200Main Menu

To View the Report:

F8

Print/View

F3

Select

F10

View File

IF (!T4:0.DN) THEN

TON (T4:0, 0.01, 100, 0);

ELSEIF (T4:0.DN) THEN

RES (T4:0);

END_IF;

WHILE (TIMER1) DO

FOR (N7:10 := 0 TO 10) DO

CASE (N7:20) OF

0:

N7:100 := TIMER8;

1:

N7:101 := TIMER9;

END_CASE;

END_FOR;

END_WHILE;Cursor to the processorname you want


40/75

Chapter

4

4-1


Monitoring Structured Text

Use this chapter to learn how to use the Structured Text View window and

the PowerText feature as monitoring tools for structured text.

The PowerText feature is an online enhancement to structured text that

integrates actual real-time data table values with the structured text source

program. While the processor is in Run mode, the view window displays

variable values in { } braces and intensifies bit operands when true. It alsodisplays I/O forcing information, indicating the force value (ON or OFF)

and whether forces are enabled or disabled by changing color. The

PowerText feature is especially useful for maintenance purposes.

Important: The PowerText features intensification does not take the

context of an address into account. If you use a NOT operator (!) before

an address in a structured text file, the address is intensified by the

PowerText feature when the address is true and is not intensified when the

address is false.

To get to the monitor/view screen to monitor program files and to display

PowerText information, follow the steps on the next page.

Empty Structured Text File


MONITOR 11 >

Rem Prog Forces: None Edits: None 5/40 File RUNBATCH

Change Exit Edit Data Edit

Mode DBASE Monitor

F1 F3 F5 F8 F10

cursor tostructured text file

ProgramDirectory

F8

Monitor File

When monitoring a structured text file, press F7Alt to toggle between

displaying or suppressing documentation.

ChapterObjectives

Using PowerText

TIP


41/75

Monitoring Structured TextChapter 4

4-2


If the processor is not in Run mode, the view window displays the

structured text that you entered.


MONITOR 11 >

Rem Run Forces: Enabled Edits: None 5/40 Addr 16 ST

Change Exit Edit Data

Mode DBASE Monitor

F1 F3 F5 F8

IF (LIMIT_SW1 {F ON} AND BOXPRESENT) THEN

GATE1 := OPEN;

GATE2 := CLOSE;

ELSIF ((LIMIT_SW2 OR (WEIGHT { 287} SETPOINT { 289}))) THEN

GATE1 := CLOSE;

GATE2 := CLOSE;

ELSIF (LIMIT_SW3 XOR LIMIT_SW4) THEN

GATE1 := CLOSE;

GATE2 := CLOSE;

ELSE

GATE1 := OPEN;

GATE2 := CLOSE;

END_IF;

ProgramDirectory

F8


Monitor File

If you havent entered logic (structured text) into the program file yet,this window says only: Empty Structured Text File

6200Main Menu

F1

Online Prog

F3

Offline Prog

or

If you have not created a structured text file,you need to do so. See page 3-1.

SFCMain Menu

MCP or Subroutine Within an SFC:

If you have not configured the Action Window toappear on the screen, press

Cursor to the structured textfield and press Enter

Alt A

Alt A (a cursor appears in the action window)

PowerText values


42/75


4-3


Configuring Display Colors

You can change the colors that the PowerText feature uses to display

information. To do this, follow the steps on the left:

+========================= PLC-5 PROGRAMMING SOFTWARE =======================+

| |

| A 6200 Series Software Product |

| += COLOR SELECTION MONOCHROME =========================================+ |

| | + Main Displays + Informational Messages | |

| | | True Logic | Errors | |

| | | Forces | User Prompts | |

| | | Rung/Step Comments | User Input | |

| | | Address Comments | Processor Status | |

| | | Instruction Comments | Program Modes | |

| | | Symbols | Test Modes | |

| | | Instruction Cursor | Run Modes | |

| | ++ Faults | |

| | Logo/Processor Directory Function Keys | |

| | Processor Dir. Cursor Data Entry Windows | |

| | Selection Windows Option Windows | |

| | Selection Cursor Who | |

+==+= ESC exits/ALTU aborts changes =======================================+==+

Press a function key

Mono/ Recall Bakgrnd Forgrnd Save

DfltClr LastClr Color Color Config

F1 F2 F5 F6 F9

F6

6200 Main Menu

SoftwareConfig

F3

Color

Selection

If you want to change the color mode, press this key

If you just installed yourprogramming software, the defaultcolor selection is monochrome.

If you have a monochromemonitor, use the default selection.If you use color choices on amonochrome monitor, someitems may be difficult orimpossible (invisible) to read. Forexample, if your monitor ismonochrome, and you set thebackground color for theinstruction cursor the same as thatfor main displays, the cursoris invisible.

This Selection: Applies to: Displays in:

True Logic display of bit values andother values

the foreground color you configure for True Logicand the background color you configure forOption Windows

False Logic the foreground and background color youconfigure for Option Windows

Forces whether forces are enabled when enabled, the foreground color you configurefor Forces and the background color you configurefor Option Windows

when disabled, the foreground and backgroundcolor you configure for Option Windows

Option Windows the structured text view window the foreground and background color you

configure for Option WindowsData Entry Windows the structured text edit window the foreground and background color you

configure for Option Windows


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4-4


If You Want to: Press this Key:

Toggle between a black and white display or a display that uses the

default colors.

[F1] Monochrome/Default Color

Restore the last color selections that were saved before the currentprogramming session. This restores color for all display options.Configurations saved during the current session are not recalled.

[F2] Recall Last Color

Toggle through the eight available color choices for backgrounds. [F5] Background Color

Toggle through the 16 available color choices for foregrounds. [F6] Foreground Color

Save the color options to disk. [F9] Save Configuration

Use the color selections you speci fy for this editing session only. [Enter ][Esc]

Cancel any changes you made on this screen for the current editing session. [Alt-U]

With the PowerText feature, you can create custom data table monitoringscreens using structured text assignments. This is a convenient way to

monitor non-adjacent data table values.

The processor updates PowertText values on the screen when the processor

is in Run mode. To see these values, create a structured text file that is not

executing as an MCP, subroutine, or an action or transition within an SFC

file. Because the structured text file is not executing, the logic in the file is

not executed. Data table values for these variables, however, are

accurately updated.

To create a monitoring screen, follow these steps:

1. Create a new structured text file.

Important: Be sure that this file is not executed as an MCP, subroutine, or

as an SFC action or transition.

2. Edit the file, and create variable and/or bit assignments.

For example:

IF(0 = 1) THEN

FLOW_RATE1 := FLOW_RATE2;

N10:0 := N10:1;

B3:0 := B19:7;

D9:0 := D20:1;

N10:10 := F8:10;END_IF;

If you want, you can perform math or logic expressions to increase

the number of values that can display on one screen. For example:

N10:0:= N10:1 + N31:231 + N26:34;

B3/3 := (B3/4 OR (((B3/5 OR B3/6) OR B3/7) OR B3/8));

Creating a ConfigurableData Monitor


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4-5


3. Accept the edits and change the processor mode to Run. The

PowerText values update. For example:

IF(0 = 1) THEN

FLOW_RATE1{ 326.07} := FLOW_RATE2{ 119.923};

N10:0{ 4095} := N10:1{ 4095};

B3:0{0000 0000 0000 0001} := B19:7{0000 0000 0000 0000};

D9:0{FFFF} := D20:1{FC3A};

N10:0{ 4095} := N10:1{ 4095} + N31:231 { 1413} + N26:34{ 57};

B3/3 := (B3/4OR (((B3/5 OR B3/6) OR B3/7) OR B3/8));

N10:10 { 2000} := F8:10 { 2000.00};

END_IF;

Important: Do not use parentheses around the variables when creating a

data monitor screen or a syntax error results. For example, do not type

(B3:0 := B3:1); Using parentheses in a situation like this results in a

syntax error.

In Run mode, structured texts PowerText feature displays instructions

sub-elements data differently than ladder does. In structured text,

sub-elements are always displayed as integers even if ladder displays the

sub-element as ASCII.

Field Widths

The width of each data type field displayed by the PowerText feature

varies. For the width of a particular data type field, see the following table.

Data Type: Field Width:

integer 6

decimal 4

float 14

ASCII 6

Binary (word) 19


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Appendix

A

A-1


Application Examples

This appendix provides programing examples and tips on debugging structured

text programs.

ATTENTION: These examples are meant to help you create your

own structured text programs. They may need modification to work

correctly on your processor system.

You can program the logic in this example in several ways using structured text.

Method A uses 3 words of memory, the same as the ladder example. Method B

uses 24 words, and method C uses 34 words.

Example: Free Running Timer

EN

TON

TIMER ON DELAY

Timer

Time base

Preset

Accum

T4:0

0.01

100

0

DN

T4:0

DN

LADDER:

STRUCTURED TEXT: METHOD A:!T4:0.DN TON (T4:0, 0.01, 100, 0);

METHOD B:IF (!T4:0.DN) THEN

TON (T4:0, 0.01, 100, 0);

ELSE

RES (T4:0);

END_IF;

METHOD C:IF (!T4:0.DN) THEN

TON (T4:0, 0.01, 100, 0);

ELSIF (T4:0.DN) THEN

RES (T4:0);

END_IF;

All of the programming examples execute the timer until the preset equals the

accumulated value. The timer is then reset and begins timing again.

AppendixObjectives

Programming a FreeRunning Timer


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Application ExamplesAppendix A

A-2


The following program sorts numbers in ascending order.

MAX_INDEX := MIN_INDEX + MAX_LOTS;UNSORTED := 0;

START_I := MIN_INDEX + 1;

FOR (UNSORTED := START_I TO MAX_INDEX) DO

NEW_LOT := N7:[N7:301];

LOCATION := UNSORTED;

PREVIOUS_LOCATION := LOCATION 1;

WHILE (LOCATION > MIN_INDEX) AND (N7:[N7:[N7:309] > NEW_LOT) DO

N7:[N7:303] := N7:[N7:309];

LOCATION := LOCATION 1;

PREVIOUS_LOCATION := LOCATION 1;

END_WHILE;

N7:[N7:303] := NEW_LOT;

END_FOR;

To help locate and trace the execution of a structured text program, set a

variable at the beginning of each program file and store the file number. Then

in various locations throughout the structured text program, update a state

variable. For example:

FILE := 3;

STATE := 0;

structured text code

.

.

.

STATE := 1;


.

.

.

STATE := 2;


.

.

.

STATE := 3;

Use PowerText to monitor the structured text file to determine where the

processor is executing. You can also use your operator interface to monitor the

FILEand STATEvalues to determine where the processor is executing.

Programming a Sort Routine

Debugging Programs


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Appendix

B

B-1


Ladder Functions Reference

This appendix lists the available ladder instructions for structured text and their

operands and the data types/values that are valid for each operand.

The following table explains each valid data type/value:

This Data Type/Value: Accepts:

immediate(program constant)

any value between -32768 and 32767

integer any integer data type: integer, timer, counter, status, bit, input, output,ASCII, BCD, control (e.g. N7:0, C4:0, etc.)

float any floating point data type (valid range is + 1.1754944e-38to+3.4028237e+38). Note that the 1784-T50 may round or truncate thenumber based on the number of significant digits and the size of thefloating point number.

block transfer any block transfer data type (e.g. BT14:0) or integer data type (e.g. N7:0)

PID any PID data type (e.g. PD16:0) or integer data type (e.g. N7:0)

string any string data type (e.g. ST12:0)

SFC status any SFC status data type (e.g. SC17:0)

Table B.A shows the PLC-5 instructions you can program in structured text, the

syntax, and the operands for those instructions. Some ladder functions are

transitional and do not operate properly if not scanned with a false rung status.

Table B.A also lists whether a false-to-true transition is required for execution.

Structured text is only supported on enhanced PLC-5 series C, revision C and

later processors.

Important: This appendix lists the instructions you can use in structured text

programs. There are additional instructions that you can use in ladder logic

programs. For a complete list of instructions, see the PLC-5 Instruction Set

Reference, publication 6200-6.4.11.

AppendixObjectives

Instruction Operands andValid Data Types


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Ladder Functions ReferenceAppendix B

B-2


Table B.AProgramming Instructions and Operands

Instruction Descriptionstructured-text syntax

Operand Valid Value RequireFalse-to-TrueTransition

ABL ASCII Test Buffer for Line channel immediate, 04 integer yes

ABL (channel, control, characters) control control address

characters integer

(this is a display only field inladder logic)

ACB ASCII Number of Characters in Buffer channel immediate, integer yes

ACB (channel, control, characters) control control address

characters integer


yes

ACI ASCII String to Integer source string no

ACI (source, destination) destination integer

ACN ASCII String Concatenate source A string no

ACN (source_A, source_B, destination) source B string

ACS Arc Cosine

ACS (source, destination)

source immediate, float (in radians),integer

no

destination float (in radians), integer

ADD ADD source A immediate, integer, float no

ADD (source_A, source_B, destination) source B immediate, integer, float

destination integer, float

AEX String Extract source string no

AEX (source, index, number, index immediate, 0-82 integerdestination)

number immediate, 0-82 integer

destination string

AFI Always False

AFI

no

AHL ASCII Set/Reset Handshake Lines channel immediate, 0-4 integer yes

handshake AND mask immediate, Hex integer

handshake OR mask immediate, Hex integer

control control

AIC ASCII Integer to String source immediate, integer no

AIC (source, destination) destination string


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B-3


Instruction RequireFalse-to-TrueTransition

Valid ValueOperandDescriptionstructured-text syntax

ARD ASCII Read Characters channel immediate, 0-4 integer yes

ARD (channel, destination, control, destination stringstring_length, characters_read)

control control address

string length 0 82

characters read integer


ARL ASCII Read Line channel immediate, 0-4 integer yes

ARL (channel, destination, control, destination stringstring_length, characters_read)


string length 0 82

characters read integer


ASC ASCII String Search source string no

ASC (source, index, search, result) index immediate, 0-4 integer

search string

result integer

ASN Arc Sine source immediate, float (in radians) no

ASN (source, destination) destination float (in radians)

ASR ASCII String Compare source A string no

ASR (source_A, source_B) source B string

ATN Arc Tangent source immediate, float (in radians) no

ATN (source, destination) destination float (in radians)

AVE Average File file integer, float yes

AVE (file, destination, control,

length, position)destination integer, float


length 1 1000

position 0 999

AWA ASCII Write with Append channel immediate, 0-4 integer yes

AWA (channel, source, control, source stringstring_length, characters_sent)


string length 0 82

characters sent integer



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B-4




AWT ASCII Write channel immediate, integer yes

AWT (channel, source, control, source stringstring_length, characters_sent)


length 0 82

characters sent integer


BSL Bit Shift Left file binary yes

BSL (file, control, bit_address, control control addresslength)

bit address bit

length 1 16000 (length in bits)

BSR Bit Shift Right file binary yes

BSR (file, control, bit_address, control control addresslength)

bit address bit


BTD Bit Distribute source immediate, integer no

BTD (source, source_bit, destination,

destination bit, len th)source bit immediate, (0 15) integer

es na on_ , eng

destination integer

destination bit immediate (0 15)

length immediate (1 16)


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B-5




BTR Block Transfer Read rack 00-277 octal yes

BTR (rack, group, module, group 0-7control_block, data_file, BT_length,

continuous, BT_timeout) module 0-1

control block BT address

integer address

data file integer

length 0, 1-64

continuous YES, NO

BTW Block Transfer Write rack 00-277 octal yes

BTW (rack, group, module, group 0-7control_block, data_file, BT_length,continuous, BT_timeout) module 0-1_

control block BT address

integer address

data file integer

length 0, 1-64

continuous YES, NO

CLR Clear

CLR destination

destination integer, float no

CMP Compare

CMP (expression) output instruction

expression, relative

expression, expression

expression using values or

addresses with evaluators

no

this instruction must be followed by an output instructionto compile correctly

COP File Copy source array no

COP (source, destination, length) destination array


COS Cosine source immediate, float (in radians) no

COS (source, destination) destination float (in radians)

CPT Compute destination integer, float no

CPT (destination, expression) math expression expression using values or

immediate integer, floataddresses with evaluators

CTD Count Down counter counter yes

CTD (counter, preset, accumulated) PRE 32768 +32767

ACC 32768 +32767

In non-continuous mode, BTR and BTW ladder functions requires a false-to-true transition to execute. In continuous mode, once the rung goes true, BTR and BTW functions continue to

execute regardless of rung condition.


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B-6




CTU Count Up counter counter yes

CTU (counter, preset, accumulated) PRE 32768 +32767

ACC 32768 +32767

DDT Diagnostic Detect source array binary yes

DDT (source, reference, result, reference array binarycompare_control, length, position,

result_control, length, position) result array integer_

compare control control address


position 0 15999

result control control address

length 1 1000

position 0 999

DEG Degree (convert radians to degrees) source immediate, float (in radians) no

DEG (source, destination) destination immediate, float (in degrees)

DIV Divide source A immediate, integer, float no

DIV (source_A, source_B, destination) source B immediate, integer, float


DTR Data Transitional source immediate, integer no

DTR (source, mask, reference) output

instruction mask immediate, integer


reference integer

EOT End of Transition

EOT

no

EQU Equal

EQU (source_A, source_B) output

source A immediate, integer, float no

nstruct on


source B immediate, integer, float

FAL File Arithmetic/Logical control control address yes

FAL (control, length, position, mode, length 1 1000destination, expression)

position 0 999

mode (INC, 11000, ALL)


expression indexed math instruction


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B-7




FBC File Bit Compare source array binary yes

FBC (source, reference, result, reference array binary compare_control, length, position,

result_control, length, position) result array integer

compare control control address


position 0 15999

result control control address

length 1 1000

position 0 999

FFL FIFO Load source immediate, indexed, integer yesFFL (source, FIFO, control, length, FIFO array indexed, integerposition)


length 1 1000

position 0 999

FFU FIFO Unload FIFO array indexed, integer yes

FFU (FIFO, destination, control, destination indexed, integerlength, position)


length 1 1000

position 0 999

FLL Fill File source immediate, integer, float no

FLL (source, destination, length) destination array array


FRD From BCD source immediate, integer no

FRD (source, destination) destination integer

FSC File Search and Compare control control structure address yes

FSC (control, length, position, mode, length 1 1000expression) output instruction

s s s e ll e a sposition 0 999

thi in truction mu t b fo ow d by n output in tructionto compile correctly mode immediate, integer (0, INC,

11000, ALL)expression indexed math instruction

GEQ Greater Than or Equal To

GEQ (source_a, source_B) output


instruction




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B-8




GRT Greater Than

GRT (source_a, source_B) output


instruction



IIN Immediate Input

IIN input_word

I (input word) immediate, integerPLC-5/10, 11, 12 15, 20, 25,30: 000-077PLC-5/40, 40L: 000-157PLC-5/60, 60L, 80, :000-237

no

IOT Immediate Output

IOT output_word

O (output word) immediate, integerPLC-5/40, 40L: 000-157

PLC-5/60, 60L, 80: 000-237

no

JSR Jump to Subroutine ladder f ile number immediate (2 999), integer no

JSR (file_number,

number_of_input_parameters,number of inputparameters

immediate, integer

input_parameter_list,

return_parameter_list) input parameter list immediate, integer, float_ _

return parameter list integer, float

LEQ Less Than or Equal To

LEQ (source_a, source_B) output


instruction



LES Less ThanLES (source_a, source_B) output


instruction



LIM Limit low limit immediate, integer, float no

LIM (low_limit, test, high_limit)

output instruction test immediate, integer, float


high limit immediate, integer, float

LFL LIFO Load source immediate, indexed, integer yes

LFL (source, LIFO, control, length, LIFO array indexed, integerposition)


length 1 1000

position 0 999


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B-10




OSF One Shot Falling storage bit bit yes

OSF (storage_bit, output_bit,

output_word) output instruction output bit immediate


output word word

OSR One Shot Rising storage bit bit yes

OSR (storage_bit, output_bit,

output_word) output instruction output bit immediate


output word word

OTE Output Energize

OTE bit

destination bit bit no

OTL Output Latch

OTL bit


OTU Output Unlatch

OTU bit


PID PID control PD address no

PID (control, process_variable, control integer address yestieback, control_variable)

process variable integer

tieback immediate, integer

control variable integer

RAD Radian (convert degrees to radians) source immediate, float (in degrees) no

RAD (source, destination) destination float (in radians)

RES Timer/Counter Reset

RES address

address timer, counter, orcontrol address

no

RET Return

RET (return_parameter_list)

return parameter list immediate, integer, float no

RTO Retentive Timer On time base immediate (0.01, 1.0) yes

RTO (timer, time base, preset, PRE 0 32767accumulated)

ACC 0 32767

SBR SubroutineSBR (input_parameter_list)

input parameter list integer, float no

SFR SFC reset SFC file number immediate (1 999) no

SFR (file_number, restart_at_step) restart at step immediate, integer

This instruction requires periodic scans to be updated.


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B-11




SIN Sine source immediate, float (in radians) no

SIN (source, destination) destination float (in radians)

SQI Sequencer Input file integer, indexed no

SQI (file, mask, source, control,

length, position) output instructionmask immediate, Hex indexed,

integer

this instruction must be followed by an output instructionle e l

source immediate, indexed, integerto compi corr ct y


length 1 1000

position 0 999

SQL Sequencer Load file integer, indexed yes

SQL (file, source, control, length, source immediate, indexed, integerposition)


length 1 1000

position 0 999

SQO Sequencer Output file integer, indexed yes

SQO (file, mask, destination, control, mask immediate, indexed, integerlength, position)

destination indexed, integer


length 1 1000

position 0 999

SQR Square Root source immediate, integer, float no

SQR (source, destination) destination integer, float

SRT Sort sort file integer, float yes

SRT (file, control, length, position) control control address

length 1 1000

position 0 999

STD Standard Deviation standard deviation file integer, float yes

STD (file, destination, control, destination integer, floatlength, position)

control control addresslength 1 1000

position 0 999

SUB Subtract source A immediate, integer, float no

SUB (source_A, source_B, destination) source B immediate, integer, float



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B-12




TAN Tangent source immediate, float (in radians) no

TAN (source, destination) destination float (in radians)

TOD To BCD source immediate, integer no

TOD (source, destination) destination integer

TOF TimerOff Delay timer timer yes: requires

TOF (timer, time base, preset, time base immediate (0.01, 1.0)atruetofalse

accumulated)PRE 0 32767

tru to ftransition to

ACC 0 32767execute

TON Timer On Delay timer timer yes

TON (timer, time base, preset, time base immediate (0.01, 1.0)accumulated)

PRE 0 32767

ACC 0 32767

UID User Interrupt Disable

UID

no

UIE User Interrupt Enable

UIE

no

XIC Examine On

XIC bit output instruction

this instruction must be followed by an output instruction

to compile correctly

source bit bit no

plc structured text

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