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

Programming Manual
Logix 5000 Controllers Function Block
Diagram
1756 ControlLogix, 1756 GuardLogix, 1769 CompactLogix,
1769 Compact GuardLogix, 1789 SoftLogix, 5069 CompactLogix,
5069 Compact GuardLogix, Studio 5000 Logix Emulate

Important user information
Read this document and the documents 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
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In no event will Rockwell Automation, Inc. be responsible or liable for indirect or consequential damages resulting from the use or
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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.
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WARNING: Identifies information about practices or circumstances that can cause an explosion in
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Important: Identifies information that is critical for successful application and understanding of the product.
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Trademarks not belonging to Rockwell Automation are property of their respective companies.

Rockwell Automation Publication 1756-PM009G-EN-P - February 2018 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.
Subject Reason
Updated Logix Designer
application screen shots. The Studio 5000 Logix Designer® interface has been modified in versions 31 and later.
Updated supported controller
models. Added 5069 CompactGuardLogix to the list of supported controllers.
New or enhanced features
None in this release.

Rockwell Automation Publication 1756-PM009G-EN-P - February 2018 5
Table of contents
Studio 5000 environment................................................................................ 7
Additional resources....................................................................................... 8
Legal notices................................................................................................... 8
Chapter 1
Introduction................................................................................................... 11
Choose the function block elements............................................................. 12
Choose a tag name for an element................................................................ 12
Define the order of execution....................................................................... 13
Data latching .......................................................................................... 13
Order of execution.................................................................................. 15
Resolve a loop........................................................................................ 16
Resolve data flow between two blocks .................................................. 17
Create a one scan delay.......................................................................... 18
Summary ................................................................................................ 18
Identify any connectors................................................................................. 18
Define program/operator control.................................................................. 19
Add a sheet ................................................................................................... 21
Add a function block element....................................................................... 22
Create a text box........................................................................................... 23
Language switching................................................................................ 23
Connect elements.......................................................................................... 24
Show or hide a pin.................................................................................. 24
Wire elements together........................................................................... 25
Mark a wire with the Assume Data Available indicator ........................ 25
Assign a tag................................................................................................... 26
Create and assign a new tag ................................................................... 26
Assign an existing tag ............................................................................ 27
Assign an immediate value (constant).......................................................... 28
Use an IREF........................................................................................... 28
Enter a value in the tag of a block.......................................................... 28
Connect blocks with an OCON and ICON................................................... 29
Add an OCON........................................................................................ 29
Add an ICON ......................................................................................... 29
Rename a wire connector....................................................................... 29
Rename a connector group..................................................................... 30
Verify the routine.......................................................................................... 30
Preface
Program a Function
Block Diagram
Index

Rockwell Automation Publication 1756-PM009G-EN-P - February 2018 7
Preface
This manual shows how to program Logix 5000 controllers with the function
block diagram (FBD) programming language. 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 that is 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.
Studio 5000
environment

Preface
8Rockwell Automation Publication 1756-PM009G-EN-P - February 2018
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.
You can view or download publications at
http://www.rockwellautomation.com/literature. To order paper copies of
technical documentation, contact your local Rockwell Automation distributor
or sales representative.
Copyright notice
Copyright © 2018 Rockwell Automation Technologies, Inc. All Rights
Reserved. Printed in USA.
This document and any accompanying Rockwell Software products are
copyrighted by Rockwell Automation Technologies, Inc. Any reproduction
and/or distribution without prior written consent from Rockwell Automation
Technologies, Inc. is strictly prohibited. Please refer to the license agreement
for details.
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.
Other 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 can be located at their respective web
site(s).
You may alternately obtain complete Corresponding Source code by
contacting Rockwell Automation via our 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.
Additional
resources
Legal notices

Preface
Rockwell Automation Publication 1756-PM009G-EN-P - February 2018 9
The following open source software is used in this product:
Software Copyright License Name License Text
AngularJS Copyright 2010-2017 Google, Inc. MIT License AngularJS 1.5.9 License
Bootstrap Copyright 2011-2017 Twitter, Inc.
Copyright 2011-2017 The Bootstrap Authors MIT License Bootstrap 3.3.7 License
jQuery Copyright 2005, 2014 JS Foundation and
other contributors MIT License jQuery 2.1.1 License
OpenSans Copyright 2017 Google, Inc. Apache License,
Version 2.0 OpenSans License
Trademark Notices
Allen-Bradley, ControlBus, ControlFLASH, Compact GuardLogix, Compact
I/O, ControlLogix, CompactLogix, DCM, DH+, Data Highway Plus,
DriveLogix, DPI, DriveTools, Explorer, FactoryTalk, FactoryTalk
Administration Console, FactoryTalk Alarms and Events, FactoryTalk Batch,
FactoryTalk Directory, FactoryTalk Security, FactoryTalk Services Platform,
FactoryTalk View, FactoryTalk View SE, FLEX Ex, FlexLogix, FLEX I/O,
Guard I/O, High Performance Drive, Integrated Architecture, Kinetix,
Logix5000, Logix 5000, Logix5550, MicroLogix, DeviceNet, EtherNet/IP,
PLC-2, PLC-3, PLC-5, PanelBuilder, PowerFlex, PhaseManager, POINT
I/O, PowerFlex, Rockwell Automation, RSBizWare, Rockwell Software,
RSEmulate, Historian, RSFieldbus, RSLinx, RSLogix, RSNetWorx for
DeviceNet, RSNetWorx for EtherNet/IP, RSMACC, RSView, RSView32,
Rockwell Software Studio 5000 Automation Engineering & Design
Environment, Studio 5000 View Designer, SCANport, SLC, SoftLogix,
SMC Flex, Studio 5000, Ultra 100, Ultra 200, VersaView, WINtelligent,
XM, SequenceManager are trademarks of Rockwell Automation, Inc.
Any Rockwell Automation logo, software or hardware product not
mentioned herein is also a trademark, registered or otherwise, of Rockwell
Automation, Inc.
Other Trademarks
CmFAS Assistant, CmDongle, CodeMeter, CodeMeter Control Center, and
WIBU are trademarks of WIBU-SYSTEMS AG in the United States and/or
other countries. Microsoft is a registered trademark of Microsoft Corporation
in the United States and/or other countries. ControlNet is a trademark of
ControlNet International. DeviceNet is a trademark of the Open DeviceNet
Vendors Association (ODVA). Ethernet/IP is a trademark of ControlNet
International under license by ODVA.
All other trademarks are the property of their respective holders and are
hereby acknowledged.

Preface
10 Rockwell Automation Publication 1756-PM009G-EN-P - February 2018
Warranty
This product is warranted in accordance with the product license. The
product’s performance may be affected by system configuration, the
application being performed, operator control, maintenance, and other related
factors. Rockwell Automation is not responsible for these intervening factors.
The instructions in this document do not cover all the details or variations in
the equipment, procedure, or process described, nor do they provide
directions for meeting every possible contingency during installation,
operation, or maintenance. This product’s implementation may vary among
users.
This document is current as of the time of release of the product; however,
the accompanying software may have changed since the release. Rockwell
Automation, Inc. reserves the right to change any information contained in
this document or the software at any time without prior notice. It is your
responsibility to obtain the most current information available from Rockwell
when installing or using this product.
Environmental compliance
Rockwell Automation maintains current product environmental information
on its website at
http://www.rockwellautomation.com/rockwellautomation/about-
us/sustainability-ethics/product-environmental-compliance.page
Contact Rockwell Automation
Customer Support Telephone — 1.440.646.3434
Online Support — http://www.rockwellautomation.com/support/

Rockwell Automation Publication 1756-PM009G-EN-P - February 2018 11
Chapter 1
Program a Function Block Diagram
To make it easier to navigate through a function block routine, divide the
routine into a series of sheets.
•Sheets help you organize and find your function blocks. They do not
affect the order in which the function blocks execute.
•When the routine executes, all the sheets execute.
•In general, use one sheet for each device, such as a motor or valve
Example: Function block routine divided into sheets
Introduction

Chapter 1
Program a Function Block Diagram
12 Rockwell Automation Publication 1756-PM009G-EN-P - February 2018
To control a device, use these elements.
To choose the function block elements, use these guidelines.
If you want to: Then use this element:
Supply a value from an input device or tag Input reference (IREF)
Send a value to an output device or tag Output reference (OREF)
Perform an operation on an input value or values and
produce an output value or values Function block
Transfer data between function blocks when they are:
•Far apart on the same sheet.
•On different sheets within the same routine.
Output wire connector (OCON) and an input wire
connector (ICON)
Disperse data to several points in the routine Single output wire connector (OCON) and multiple input
wire connectors (ICON)
Each function block uses a tag to store configuration and status information
about the instruction.
•When you add function block instruction, the Logix Designer
application automatically creates a tag for the block. Use this tag,
rename the tag, or assign a different tag.
•For IREFs and OREFs, create a tag or assign an existing tag.
For a: Specify:
Tag tag_name
Bit number of a larger data type tag_name.bit_number
Member of a structure tag_name.member_name
Element of a one dimension array tag_name[x]
Choose the function
block elements
Choose a tag name
for an element

Program a Function Block Diagram
Chapter 1
Rockwell Automation Publication 1756-PM009G-EN-P - February 2018 13
For a: Specify:
Element of a two dimension array tag_name[x,y]
Element of a three dimension array tag_name[x,y,z]
Element of an array within a structure tag_name.member_name[x]
Member of an element of an array tag_name[x,y,z].member_name
where:
x is the location of the element in the first dimension.
y is the location of the element in the second dimension.
z is the location of the element in the third dimension.
For a structure within a structure, add an additional member_name.
Define execution order (flow of data) by wiring elements together and
indicating any input (feedback) wires, if necessary. The location of a block
does not affect the order in which the blocks execute.
If you use an IREF to specify input data for a function block instruction, the
data in that IREF is latched for the scan of the function block routine. The
IREF latches data from program-scoped and controller-scoped tags. The
controller updates all IREF data at the beginning of each scan as shown in
this diagram.
In this example, the value of tagA is stored at the beginning of the execution
of the routine. The stored value is used when Block_01 executes. The same
stored value is also used when Block_02 executes. If the value of tagA
Define the order of
execution
Data latching

Chapter 1
Program a Function Block Diagram
14 Rockwell Automation Publication 1756-PM009G-EN-P - February 2018
changes during execution of the routine, the stored value of tagA in the IREF
does not change until the next execution of the routine.
This example is the same as the previous example. The value of tagA is
stored only once at the beginning of the execution of the routine. The routine
uses this stored value throughout the routine.
With version 11 and later of the application, use the same tag in multiple
IREFs and an OREF in the same routine. Because the values of tags in IREFs
are latched every scan through the routine, all IREFs use the same value,
even if an OREF obtains a different tag value during execution of the routine.
In this example, if tagA has a value of 25.4 when the routine starts executing
this scan, and Block_01 changes the value of tagA to 50.9, the second IREF
wired into Block_02 still uses a value of 25.4 when Block_02 executes this
scan.

Program a Function Block Diagram
Chapter 1
Rockwell Automation Publication 1756-PM009G-EN-P - February 2018 15
The new tagA value of 50.9 is not used by any IREFs in this routine until the
start of the next scan.
The Logix Designer application automatically determines the order of
execution for the function blocks in a routine.
•When you verify a function block routine.
•When you verify a project that contains a function block routine.
•When you download a project that contains a function block routine.
Define the order of execution by wiring function blocks together and
indicating the data flow of any feedback wires, if necessary.
If function blocks are not wired together, it does not matter which block
executes first. There is no data flow between the blocks.
If the blocks are wired sequentially, the order of execution moves from input
to output. The inputs of a block require data to be available before the
controller can execute that block. In this example, block 2 has to execute
before block 3 because the outputs of block 2 feed the inputs of block 3.
The order of execution is only relative to the blocks that are wired together.
The two groups of blocks in this example are not wired together. The blocks
Order of execution

Chapter 1
Program a Function Block Diagram
16 Rockwell Automation Publication 1756-PM009G-EN-P - February 2018
within a specific group execute in the appropriate order in relation to the
blocks in that group.
To create a feedback loop around a block, wire an output pin of the block to
an input pin of the same block. In this example, the loop contains only a
single block, so execution order does not matter.
If a group of blocks are in a loop, the controller cannot determine which
block to execute first, and it cannot resolve the loop, as illustrated in this
example.
To identify which block to execute first, mark the input wire that creates the
loop (the feedback wire) with the Assume Data Available indicator. In this
example, block 1 uses the output from block 3 that was produced in the
previous execution of the routine.
The Assume Data Available indicator defines the data flow within the loop.
The arrow indicates that the data serves as input to the first block in the loop.
Resolve a loop

Program a Function Block Diagram
Chapter 1
Rockwell Automation Publication 1756-PM009G-EN-P - February 2018 17
Do not mark all the wires of a loop with the Assume Data Available
indicator.
This example is OK.
This example is not OK.
The Assume Data Available indicator defines the data flow
within the loop.
The controller cannot resolve the loop because all the wires
use the Assume Data Availableindicator.
If you use two or more wires to connect two blocks, use the same data flow
indicators for all of the wires between the two blocks.
This is OK
This is NOT OK
In this example, neither wire uses the Assume Data
Available indicator.
In this example, both wires use the Assume Data Available
indicator.
In this example, only one wire uses the Assume Data
Available indicator.
Resolve data flow
between two blocks

Chapter 1
Program a Function Block Diagram
18 Rockwell Automation Publication 1756-PM009G-EN-P - February 2018
Use the Assume Data Available indicator to produce a one scan delay
between blocks. In this example, block 1 executes first. It uses the output
from block 2 that was produced in the previous scan of the routine.
A function block routine executes in this order.
1. The controller latches all data values in IREFs.
2. The controller executes the other function blocks in the order
determined by how they are wired.
3. The controller writes outputs in OREFs.
Like wires, connectors transfer data from output pins to input pins. Use
connectors when:
•The elements that you want to connect are on different sheets within
the same routine.
•A wire is difficult to route around other wires or elements.
•You want to disperse data to several points in the routine.
To use connectors, use these rules.
•Each OCON requires a unique name.
•For each OCON, you must have at least one corresponding ICON, such
as an ICON with the same name as the OCON.
Create a one scan
delay
Summary
Identify any
connectors

Program a Function Block Diagram
Chapter 1
Rockwell Automation Publication 1756-PM009G-EN-P - February 2018 19
•Multiple ICONs can reference the same OCON. This lets you disperse
data to several points in your routine.
These instructions support the concept of Program/Operator control.
•Enhanced Select (ESEL)
•Totalizer (TOT)
•Enhanced PID (PIDE)
•Ramp/Soak (RMPS)
•Discrete 2-State Device (D2SD)
•Discrete 3-State Device (D3SD)
Program/Operator control lets you control these instructions simultaneously
from the user program and from an operator interface device. When in
Program control, the instruction is controlled by the Program inputs to the
instruction. When in Operator control, the instruction is controlled by the
Operator inputs to the instruction.
Program or Operator control is determined by using these inputs:
Input Description
.ProgProgReq A program request to go to Program control.
.ProgOperReq A program request to go to Operator control.
.OperProgReq An operator request to go to Program control.
.OperOperReq An operator request to go to Operator control.
To determine whether an instruction is in Program or Operator control,
examine the ProgOper output. If ProgOper bit is set, the instruction is in
Program control. If ProgOper bit is cleared, the instruction is in
Operator control.
Operator control takes precedence over Program control if both input request
bits are set. For example, if ProgProgReq and ProgOperReq bits are set,
the instruction goes to Operator control.
The Program request inputs take precedence over the Operator request
inputs. This provides the capability to use the ProgProgReq and
ProgOperReq inputs to lock an instruction in a desired control.
For example, assume that a Totalizer instruction is always used in Operator
control, and the user program never controls the running or stopping of the
Totalizer. In this case, wire a literal value of 1 into the ProgOperReq input.
Define
program/operator
control

Chapter 1
Program a Function Block Diagram
20 Rockwell Automation Publication 1756-PM009G-EN-P - February 2018
This prevents the operator from ever putting the Totalizer into Program
control by setting the OperProgReq input from an operator interface device.
Likewise, constantly setting the ProgProgReq input can "lock" the
instruction into Program control. This is useful for automatic startup
sequences when you want the program to control the action of the instruction
without an operator inadvertently taking control of the instruction. In this
example, the program sets the ProgProgReq input during the startup, and
clears the ProgProgReq input once the startup is complete. Once the
ProgProgReq input is cleared, the instruction remains in Program control
until it receives a request to change. For example, the operator sets the
OperOperReq input from a faceplate to take control of that instruction. This
example shows how to lock an instruction into Program control.