Rockwell Automation Allen-Bradley Logix 5000 Series Owner's manual

Rockwell Automation Publication 1756-PM013H-EN-P - March 2022
Supersedes Publication 1756-PM013G-EN-P - September 2020
Programming Manual
Original Instructions
Logix 5000 Controllers
ASCII Strings
1756 ControlLogix, 1756 GuardLogix, 1769 CompactLogix,
1769 Compact GuardLogix, 1789 SoftLogix, 5069
CompactLogix, 5069 Compact GuardLogix, Studio 5000
Logix Emulate

Logix 5000 Controllers ASCII Strings
2 Rockwell Automation Publication 1756-PM013H-EN-P - March 2022
Important User Information
Read this document and thedocuments listed in the additional resources section about installation, configuration, and
operation of this equipment before you install, configure, operate, or maintain this product. Users are required to familiarize
themselves with installation and wiring instructions in addition to requirements of all applicable codes, laws, and standards.
Activities including installation, adjustments, putting into service, use, assembly, disassembly, and maintenance are required to
be carried out by suitably trained personnel inaccordance with applicable code of practice.
If this equipment is used in a manner not specified by the manufacturer, the protection provided by the equipment may be
impaired.
In no event will Rockwell Automation, Inc. be responsible orliable for indirect or consequential damages resulting from the use
or application of this equipment.
The examples and diagrams in this manual are included solely for illustrative purposes. Because of the many variables and
requirements associated with any particular installation, Rockwell Automation, Inc. cannot assume responsibility or liability for
actual use based on the examples and diagrams.
No patent liability is assumed by Rockwell Automation, Inc. with respect to use of information, circuits, equipment, or software
described in this manual.
Reproduction of the contents of this manual, in whole or in part, withoutwritten permission of Rockwell Automation, Inc., is
prohibited.
Throughout this manual, when necessary, we use notes to make you aware of safety considerations.
WARNING: Identifies information about practices or circumstances that can cause an explosion in a hazardous environment, whichmay lead to personal injury
or death, property damage, or economic loss.
ATTENTION: Identifies information about practices or circumstances that can lead to personal injury or death, property damage, or economic loss. Attentions
help you identify a hazard, avoid a hazard, and recognize the consequence.
IMPORTANT
Identifies information that is critical for successful application and understanding of the product.
Labels may also be on or inside the equipment to provide specific precautions.
SHOCK HAZARD: Labels may be on or inside the equipment, for example, a drive or motor, to alert people that dangerous voltage may be present.
BURN HAZARD: Labels may be on or inside the equipment, for example, a drive or motor, to alert peoplethat surfaces may reach dangerous temperatures.
ARC FLASH HAZARD: Labels may be on or inside the equipment, for example, a motor control center, to alert people to potential Arc Flash. Arc Flash will cause
severe injury or death. Wear proper Personal Protective Equipment (PPE). Follow ALL Regulatory requirements for safe work practices and for Personal
Protective Equipment (PPE).
Rockwell Automation recognizes that some of the terms that are currently used in our industry and in this publication are not in
alignment with the movement toward inclusive language intechnology. We are proactively collaborating with industry peers to
find alternatives to such terms and making changes to our products and content. Please excuse the use of such terms in our
content while we implement these changes.

Rockwell Automation Publication 1756-PM013H-EN-P - March 2022 3
Summary of Changes
This manual includes new and updated information. Use these reference
tables to locate changed information.
Grammatical and editorial style changes are not included in this summary.
Global changes
This table identifies changes that apply to all information about a subject in
the manual and the reason for the change. For example, the addition of new
supported hardware, a software design change, or additional reference
material would result in changes to all of the topics that deal with that subject.
Change
Topic
Updated Legal notices.
Legal notices
New or enhanced features
None in this release.

Rockwell Automation Publication 1756-PM013H-EN-P - March 2022 5
Table of Contents
Studio 5000 environment ...........................................................................7
Additional resources....................................................................................7
Legal Notices ................................................................................................8
Chapter 1
Introduction.................................................................................................9
Connect the ASCII device............................................................................9
Configure the Serial Port...........................................................................10
Configure the User Protocol......................................................................12
Create string data types.............................................................................13
Read characters from the device ...............................................................14
Send characters to the device ....................................................................15
Enter ASCII characters ..............................................................................16
Chapter 2
Introduction............................................................................................... 19
Extract a part of a Bar Code ...................................................................... 19
Look up a Bar Code....................................................................................20
Create the PRODUCT_INFO Data Type ............................................20
Search for the characters.....................................................................21
Identify the Lane Number...................................................................21
Reject bad characters .......................................................................... 22
Enter the Product IDs and Lane Numbers........................................ 22
Check the Bar Code characters................................................................. 22
Convert a value ...........................................................................................23
Decode an ASCII message ........................................................................ 24
Build a string ............................................................................................. 25
Appendix A
ASCII character codes ...............................................................................27
Summary of Changes
Preface
Communicating with an ASCII
device
Processing ASCII characters
ASCII character codes
Index

Rockwell Automation Publication 1756-PM013H-EN-P - March 2022 7
Preface
This manual shows how to manipulate ASCII strings in Logix 5000
controllers. This manual is one of a set of related manuals that show common
procedures for programming and operating Logix 5000 controllers.
For a complete list of common procedures manuals, refer to the Logix 5000
Controllers Common Procedures Programming Manual, publication
1756-PM001.
The term Logix 5000 controller refers to any controller based on the Logix
5000 operating system.
The Studio 5000 Automation Engineering & Design Environment® combines
engineering and design elements into a common environment. The first
element is the Studio 5000 Logix Designer® application. The Logix Designer
application is the rebranding of RSLogix 5000® software and will continue to
be the product to program Logix 5000™ controllers for discrete, process,
batch, motion, safety, and drive-based solutions.
The Studio 5000® environment is the foundation for the future of
Rockwell Automation® engineering design tools and capabilities. The Studio
5000 environment is the one place for design engineers to develop all
elements of their control system.
These documents contain additional information concerning related
Rockwell Automation products.
Resource
Description
Industrial Automation Wiring and Grounding Guidelines,
publication 1770-4.1 Provides general guidelines for installing a Rockwell
Automation industrial system.
Product Certifications webpage, available at
http://ab.rockwellautomation.com
Provides declarations of conformity, certificates, and
other certification details.
Studio 5000 environment
Additional resources

Preface
8 Rockwell Automation Publication 1756-PM013H-EN-P - March 2022
View or download publications at
http://www.rockwellautomation.com/literature. To order paper copies of
technical documentation, contact the local Rockwell Automation distributor
or sales representative.
Rockwell Automation publishes legal notices, such as privacy policies, license
agreements, trademark disclosures, and other terms and conditions on the
Legal Notices page of the Rockwell Automation website.
End User License Agreement (EULA)
You can view the Rockwell Automation End-User License Agreement ("EULA")
by opening the License.rtf file located in your product's install folder on your
hard drive.
Open Source Licenses
The software included in this product contains copyrighted software that is
licensed under one or more open source licenses. Copies of those licenses are
included with the software. Corresponding Source code for open source
packages included in this product are located at their respective web site(s).
Alternately, obtain complete Corresponding Source code by contacting
Rockwell Automation via the Contact form on the Rockwell Automation
website:
http://www.rockwellautomation.com/global/about-us/contact/contact.page
Please include "Open Source" as part of the request text.
A full list of all open source software used in this product and their
corresponding licenses can be found in the OPENSOURCE folder. The default
installed location of these licenses is C:\Program Files (x86)\Common
Files\Rockwell\Help\<Product Name>\Release
Notes\OPENSOURCE\index.htm.
Legal Notices

Rockwell Automation Publication 1756-PM013H-EN-P - March 2022 9
Chapter 1
Communicating with an ASCII device
You can exchange ASCII data with a device through the serial port of the
controller. For example, you can use the serial port to:
•Read ASCII characters from a weigh scale module or bar code reader.
•Send and receive messages from an ASCII triggered device, such as a
MessageView terminal.
Firmware revision 3.1 and later of the 1756-EWEB EtherNet/IP Web Server
module supports the controller serial port and a socket interface that lets
Logix 5000 controllers exchange ASCII data using TCP or UDP socket
services.
To connect to the ASCII device, use these steps.
1. On the serial port of the ASCII device, determine which pins send
signals and which pins receive signals.
2. Connect sending pins to corresponding receiving pins and attach
jumpers.
Introduction
Connect the ASCII device

Chapter 1 Communicating with an ASCII device
10 Rockwell Automation Publication 1756-PM013H-EN-P - March 2022
If the communications
Then wire the connectors
Handshake
Do not handshake
3. Attach the cable shield to the connectors.
4. Connect the cable to the controller and the ASCII device.
To configure the serial port, use these steps.
1. On the Online toolbar, click the Controller Properties button.
2. On the Controller Properties dialog box, click the Serial Port tab.
Configure the Serial Port

Chapter 1 Communicating with an ASCII device
Rockwell Automation Publication 1756-PM013H-EN-P - March 2022 11
3. On the Modemenu, choose User and type the configuration settings
for the serial port.
•choose the baud rate, data bits, parity, and stop bits.
•in the Control Line menu, choose the Control Line option:
If
And
And this is the
Choose
Then
You are not using a modem
--------------------------------------------------------------->
No Handshaking
You are using a modem
Modems in a point-to-point link
are full-duplex
----------------------------->
Full Duplex
Master modem is full-duplex
while slave modem is
half-duplex
master controller.
Full Duplex
slave controller
Half Duplex
Select the Continuous Carrier check box.
All modems in the system are
half-duplex
----------------------------->
Half Duplex
Clear the Continuous Carrier check box
(default).
•in the RTS Send Delay box, type the delay (in 20 ms units) between
the time the RTS signal turns on (high) and the time that data is
sent. For example, a value of 4 produces an 80 ms delay.
•in the RTSOff Delay box, type the delay (in 20 ms units) between
the time the last character is sent and the time that the RTS signal
turns off (low).
4. Click Apply.

Chapter 1 Communicating with an ASCII device
12 Rockwell Automation Publication 1756-PM013H-EN-P - March 2022
To configure the user protocol, use these steps.
1. In the Controller Properties dialog box, click the User Protocol tab.
•Enter a buffer size greater than or equal to the greatest number of
characters in a transmission. Twice the number of characters is a
good guideline.
•For ABL or ARL instructions, enter termination characters to mark
the end of the data. For ASCII codes, see ASCII Character Codes on
page 27.
If the device sends
Then
Tips
One termination character
•
In the Termination Character 1 box, type the
hexadecimal ASCII code for the first
character.
•In the
Termination Character 2
box, type $FF.
For printable characters, such as 1 or A, type the
character.
Two termination characters
In the Termination Character 1 and 2 boxes,
type the hexadecimal ASCII code for each
character.
•For AWA instruction, enter append characters. For ASCII codes, see
ASCII Character Codes on page 27.
To append
Then
Tips
One character
•In the Append Character 1 box, type the
hexadecimal ASCII code for the first character.
•In the
Append Character 2
box, type $FF.
For printable characters, such as 1 or A, type the
character.
Two characters
In the Append Character 1 and 2boxes, type the
hexadecimal ASCII code for each character.
•If the ASCII device is configured for XON/XOFF flow control, select
the XON/XOFF check box.
•If the ASCII device is a CRT or pre-configured for half duplex
transmission, select the Echo Mode check box.
•Choose the Delete Mode using the following considerations:
Configure the User Protocol

Chapter 1 Communicating with an ASCII device
Rockwell Automation Publication 1756-PM013H-EN-P - March 2022 13
If the ASCII device is
Select
Tips
CRT
CRT
•
The DEL character ($7F) and the character that precedes the DEL character
are
not
sent to the destination.
•If echo mode is selected and an ASCII instruction reads the DEL character, the
echo returns three characters: BACKSPACE SPACE BACKSPACE ( $08 $20 $08).
Printer
Printer
•The DEL character ($7F) and the character that precedes the DEL character
are
not
sent to the destination.
•If echo mode is selected and an ASCII instruction reads the DEL character, the
echo returns two characters: / ($2F) followed by the character that was
deleted.
None of the above
Ignore
The DEL character ($7F) is treated as any other character.
2. Click OK.
Store ASCII characters in tags that use a string data type.
You can use thedefault STRING data type. It stores
up to 82 characters.
or
You can create a string data type to store the number of
characters that you define.
IMPORTANT
Use caution when you create a string data type. If you decide later to change the sizeof the
string data type, you may lose data in any tags that currently use that data type.
If you
Then
Make a string data type smaller
•
The data truncates.
•The LEN does not change.
Make a string data type larger
The data and LEN resets to zero.
Create string data types

Chapter 1 Communicating with an ASCII device
14 Rockwell Automation Publication 1756-PM013H-EN-P - March 2022
To create string data types
1. In the Controller Organizer, right-click Strings and choose New String
Type.
2. In the Name box, type the name for the data type.
3. In the Maximum Characters box, enter the maximum number of
characters that the string data type stores.
4. Select OK.
As a general rule, before you read the buffer, use an ACB or ABL instruction to
verify that the buffer contains the required characters.
•An ARD or ARL instruction continues to read the buffer until the
instruction reads the required characters.
•While an ARD or ARL instructionreads the buffer, no other ASCII
Serial Port instructions, except the ACL, can execute.
•Verifying that the buffer contains the required characters prevents the
ARD or ARL from holding up the execution of other ASCII Serial Port
instructions while the input device sends its data.
For additional information on ASCII Serial Port instructions, see Logix 5000
Controllers General Instruction Set Reference Manual
http://literature.rockwellautomation.com/idc/groups/literature/documents/rm/1756-r
m003_-en-p.pdf.
In the following example, the device sends a fixed number of characters, such
as a bar code reader:
EXAMPLE
A bar code reader sends bar codes to the serial port (channel 0) of the controller. Each bar code contains 24 characters. To
determine when the controller receives a bar code, the ACB instruction continuously counts the characters in the buffer.
When the buffer contains at least 24 characters, the controller received a bar code. The ARD instruction moves the bar code to
the bag_bar_code tag.
Read characters from the
device

Chapter 1 Communicating with an ASCII device
Rockwell Automation Publication 1756-PM013H-EN-P - March 2022 15
In the following example, the device sends a variable number of characters,
such as a message or display terminal.
EXAMPLE
Continuously test the buffer for a message.
•Because each message ends in a carriage return ($0D), the carriage return is configured as the termination character in the
Controller Properties dialog box, User Protocol tab.
•When the ABL finds a carriage return, its sets the FD bit.
When the ABL instruction finds the carriage return (MV_line.FD is set), the controller removes the characters from the buffer, up
to and including the carriage return, and places them in the MV_msg tag.
When you send characters to the device, you must determine either to send
the same number of characters each time or to append terminations
characters to the data.
In the following example, you always send the same number of characters and
want to automatically append one or two characters to the end of the data.
EXAMPLE
When the temperature exceeds the high limit(temp_high is on), the AWA instruction sends five
characters from the string[1] tag to a MessageView terminal.
•The $14 counts as one character. The hex code for the Ctrl-T character.
•The instruction also sends (appends) the characters defined in the user protocol. In this
example, the AWA instruction sends a carriage return ($0D), which marks the end of the
message.
And then to always send the same number of characters:
EXAMPLE
When the temperature reaches the low limit (temp_low is on), the AWT instruction sends nine
characters from the string[2] tag to a MessageView terminal. (The $14 counts as one character.
The hex code for the Ctrl-T character.)
Send characters to the
device

Chapter 1 Communicating with an ASCII device
16 Rockwell Automation Publication 1756-PM013H-EN-P - March 2022
In the following example, you send a different number of characters each time
and want to automatically append one or two characters to the end of the
data:
EXAMPLE
When alarm is on, the AWA instruction sends the characters in alarm_msg and appends a
termination character.
•Because the number of characters in alarm_msg varies, the rung first moves the length of
alarm_msg (alarm_msg.LEN) to the length of the AWA instruction (alarm_write.LEN).
•In alarm_msg, the $14 counts as one character. The hex code for the Ctrl-T character.
Send a different number of characters each time:
EXAMPLE
When MV_update is on, the AWT instruction sends thecharacters in MV_msg.
•Because the number of characters in MV_msg varies, the rung first moves the length of
MV_msg (MV_msg.LEN) to the length of the AWT instruction (MV_write.LEN).
•In MV_msg, the $16 counts as one character. The hex code for the Ctrl-V character.
To enter the ASCII characters, use these steps.
IMPORTANT
This String Browser window shows the characters up to the value of the LEN member of the
string tag. The string tag may contain additional data, which the String Browser window does
not show.
Enter ASCII characters

Chapter 1 Communicating with an ASCII device
Rockwell Automation Publication 1756-PM013H-EN-P - March 2022 17
1. In the AWA instruction, double-click the value area of Source.
Dollar sign ($24)
Carriage return ($0D)
Single quote ($27)
Tab ($09)
Line feed ($0A)
The number of characters that you see in the
window. The same as the LENmember of the
string tag.
New line ($0D$0A)
The maximum number of characters that the
string
tag can hold.
Form feed ($0C)
2. In the text box, type the characters for the string.
3. Click OK.

Rockwell Automation Publication 1756-PM013H-EN-P - March 2022 19
Chapter 2
Processing ASCII characters
You can process ASCII characters to do many things, including:
•Interpret a bar code and take action based on the bar code.
•Use a weight from a weigh scale when the weight is sent as ASCII
characters.
•Decode a message from an ASCII triggered device, such as an operator
terminal.
•Build a string for an ASCII triggered device using variables from your
application.
For example, a bar code may contain information about a bag on a conveyor
at an airport. To check the flight number and destination of the bag, you
extract characters 10 - 18.
Airline
Origin
Flight #
Destination
Date
Bar code
N
W
A
H
O
P
5
0
5
8
A
M
S
0
2
2
2
0
1
Character number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
5
0
5
8
A
M
S
9 characters
EXAMPLE
In the baggage handling conveyor of an airport, each bag gets a bar code. Characters 10 - 18 of
the bar code are the flight number and destination airport of the bag. After the bar code is read
(bag_read.EMis on) the MIDinstruction copies the flight number and destination airport to the
bag_flt_and_dest tag.
Introduction
Extract a part of a Bar Code

Chapter 2 Processing ASCII characters
20 Rockwell Automation Publication 1756-PM013H-EN-P - March 2022
For example, in a sorting operation, an array of a user-defined data type
creates a table that shows the lane number for each type of product. To
determine which lane to route a product, the controller searches the table for
the product ID (characters of the bar code that identify the product).
To look up a bar code, follow these procedures:
•Create the PRODUCT_INFO Data Type on page 20.
•Search for the Characters on page 21.
•Identify the Lane Number on page 21.
•Reject Bad Characters on page 22.
•Enter the Product IDs and Lane Numbers on page 22.
Tip: To copy the above components from a sample project, open the Samples folder. On theHelp
menu, click Vendor Sample Projects.
To create a Product_Info user-defined date type in the Controller Organizer,
right-click User-Defined and click New Data Type. Configure the
user-defined data type as follows.
Data Type: PRODUCT_INFO
Name
PRODUCT_INFO
Description
Identifies the destination for an item based on an ASCII string of characters that identify
the item
Members
Name
Data Type
Style
Description
Product_ID
STRING
ASCII characters that identify the item
Lane
DINT
Decimal
Destination for the item, based on its ID
Look up a Bar Code
Create the PRODUCT_INFO
Data Type