Rockwell Automation 1756 ControlLogix, 1756 GuardLogix, 1769 CompactLogix, 1769 Compact GuardLogix, 1789 SoftLogix Programming Manual

Logix 5000 Controllers

Major, Minor, and I/O Faults

1756 ControlLogix, 1756 GuardLogix, 1769 CompactLogix,

1769 Compact GuardLogix, 1789 SoftLogix, 5069

CompactLogix, 5069 Compact GuardLogix, Studio 5000

Logix Emulate

Publication 1756-PM014M-EN-P

Programming Manual

Original Instructions

Logix 5000 Controllers Major, Minor, and I/O Faults

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 out by suitably trained personnel in accordance 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 or liable 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, without written 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, which may 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 people that 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).

2	Rockwell Automation Publication 1756-PM014M-EN-P - September 2020

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

The Legal noticeshave been updated.

New or enhanced features

This table contains a list of topics changed in this version, the reason for the change, and a link to the topic that contains the changed information.

Topic Name	Reason
Minor Fault Codes on page 33	Updated the Minor Fault Code list to include minor fault type 16,
	code 1.
Major fault codes on page 25	Updated the Major Fault Code list to include major fault type 4,
	code 95.

Rockwell Automation Publication 1756-PM014M-EN-P - September 2020

3

Table of Contents

Summary of changes Preface

Major Faults

Minor Faults

I/O Fault Codes

Index

Additional resources...................................................................................	7
Legal Notices ...............................................................................................	7
Chapter 1
Major Fault State.........................................................................................	9
Recover from a major fault...................................................................	9
Important points regarding Add-On Instructions............................	10
Fault handling during prescan and postscan ....................................	11
Placement of fault routines .................................................................	12
Choose where to place the fault routine.............................................	12
Create a fault routine for a program.........................................................	13
Change a fault routine assignment of a program .............................	14
Create a routine for the controller fault handler .....................................	15
Create a routine for the power-up handler ..............................................	17
Programmatically clearing a major fault..................................................	19
Create a data type to store fault information ...................................	20
Write a routine to clear the fault.........................................................	21
Clear a major fault during prescan ..........................................................	22
Test a fault routine .....................................................................................	23
Create a user-defined major fault ............................................................	24
Major fault codes .......................................................................................	25
Chapter 2
Identify minor faults .................................................................................	31
Minor fault examples...........................................................................	32
Minor fault codes........................................................................................	33
Chapter 3
Indications of I/O faults ............................................................................	37
I/O Fault Codes .........................................................................................	38

Rockwell Automation Publication 1756-PM014M-EN-P - September 2020

5

Preface

Additional resources

Legal Notices

This manual shows how to monitor and handle major and minor controller faults. The manual also provides lists of major, minor, and I/O fault codes to use to troubleshoot the system.

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 1756PM001.

The term Logix 5000 controller refers to any controller based on the Logix 5000 operating system.

These documents contain additional information concerning related products from Rockwell Automation.

Resource	Description
Logix5000 Controllers General Instructions Reference	Provides programmers with details about each
Manual, publication 1756-RM003	available instruction for a Logix5000 controller.
Product Certifications website, http://www.ab.com	Provides declarations of conformity, certificates,
	and other certification details.

View or download publications at http://www.rockwellautomation.com/literature/. To order paper copies of technical documentation, contact your local Allen-Bradley distributor or Rockwell Automation 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

Rockwell Automation Publication 1756-PM014M-EN-P - September 2020

7

Preface

website: http://www.rockwellautomation.com/global/aboutus/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\FactoryTalk Services Platform\Release

Notes\OPENSOURCE\index.htm.

8	Rockwell Automation Publication 1756-PM014M-EN-P - September 2020

Chapter 1

Major Faults

Major Fault State

This chapter explains major fault codes and how to work with them in the Logix Designer application.

If a fault condition occurs that prevents an instruction from running, the instruction aborts and the controller reports a major fault. A major fault halts logic execution and the controller switches to faulted mode (the OK LED flashes red).

Depending on the application, you may not want all major faults to shut down the system. If you do not want all major faults to shut down the system, create a fault routine to clear the fault and let the application continue to run.

The process of resuming execution after the fault clears is known as fault recovery.

IMPORTANT	Do not use fault routines to continually clear all faults on the controller. Program the
	fault routine to be selective in the types and number of faults cleared. It is also a
	good idea to log the fault occurrence to analyze it later.
IMPORTANT	When an instruction generates an error due to a fault (for example, a COP with an
	indirect addressing programming error), the fault routine skips the instruction and
	does not run. This occurs with all instructions.

Example:	In a system that uses recipe numbers as indirect addresses, an incorrectly typed number
	could produce a major fault.
	To keep the entire system from shutting down in the event of this fault, program a fault
	routine to clear type 4, code 20, major faults.

	See also
	Create a routine for the controller fault handler on page 15
	Clear a major fault during prescan on page 22
Recover from a major fault	These examples show fault routines with logic that take specific action after a
	major fault. If the fault clears, the faulted instruction does not run and
	execution resumes with the next instruction.

Rockwell Automation Publication 1756-PM014M-EN-P - September 2020

9

Chapter 1

Major Faults

Example 1

In this example, a JSR instruction passes an input parameter containing an indirect address that is out of bounds. If the fault clears, the JSR instruction aborts (the subroutine does not run) and execution resumes with the EQU instruction.

Example 2

In this example, the logic inside an Add-On Instruction generates a fault. While the logic of an Add-On Instruction may look like a subroutine, it is not– the Add-On Instruction is an instruction. When a fault occurs inside an AddOn Instruction, the remainder of the Add-On Instruction aborts. If the fault clears, execution resumes with the MOV instruction.

Important points regarding Add-On Instructions

Keep these considerations in mind when using Add-On Instructions and major faults.

•The Add-On Instruction stops running at the instruction that caused the fault. This means that the remainder of the scan mode routine does not run.

10	Rockwell Automation Publication 1756-PM014M-EN-P - September 2020

Chapter 1

Major Faults

Fault handling during prescan and postscan

•If the fault clears, execution resumes at the instruction following the top-level Add-On Instruction invocation. For example, assume the Add-On Instruction myAoi in Example 2 invokes a nested Add-On Instruction myNested, which invokes another nested Add-On Instruction inner. Furthermore, assume that an instruction inside of inner causes a fault. If the fault clears, execution resumes with the MOV instruction (the remainder of inner does not execute; the remainder of myNested does not execute; and the remainder of myAoi does not execute.)

•During prescan:

•The Logic routine runs (in prescan mode).

•The Prescan routine runs (in normal scan mode).

•During postscan:

•The Logic routine runs (in postscan mode).

•The Postscan routine runs (in normal scan mode).

If a fault occurs while processing the Logic routine, the Add-On Instruction aborts (the remainder of the Logic routine does not run and the pre-scan and post-scan routines do not run). If the fault clears, execution resumes at the instruction following the top-level Add-On Instruction invocation.

See also

Create a fault routine for a program on page 13

The behavior of each instruction varies depending on the mode in which it runs–true, false, prescan, or postscan. For details about what a specific instruction does in each mode, see the Logix 5000 Controllers General Instructions Reference Manual, publication number 1756-RM003.

•Prescan provides a system-defined initialization of the user program when the controller switches from program mode to run mode.

•Postscan provides a system-defined re-initialization of the logic invoked from an SFC action, when the action shuts down (if SFCs are configured for Automatic Reset).

If an array index is out of range during prescan, the controller could generate a major fault. There are a number of ways this could happen: the controller loses power, encounters a major fault, or the project is saved while online. Because the user program, during prescan and postscan, cannot assign values to tags, the only way to correct these issues is to manually initialize the index variables using the Logix Designer application or to write a fault handler to ignore the array faults during prescan. To reduce the need for manual intervention, the Logix Designer application includes an internal fault

Rockwell Automation Publication 1756-PM014M-EN-P - September 2020

11

Chapter 1 Major Faults

	handler. This handler is only used during prescan and only clears array faults
	(type 4, fault codes of 20 of 83).
	Tip: Array faults are not ignored during postscan because the user program controls index tag
	values when an action is shut down.
Placement of fault routines	Use a fault routine to program logic to take specific action after a fault, such
	as clearing the fault and continuing to run. Configure fault routines to a
	program, controller, or to the Power-Up Handler.
	ProgramFaultRoutine

ControllerFaultRoutine

Power-UpFaultHandlerRoutine

Choose where to place the fault routine

See also

Create a fault routine for a program on page 13

Create a routine for the controller fault handler on page 15

Create a routine for the power-up handler on page 17

Where to place the fault routine depends on the type of fault. Use this table to determine where in the project to configure the fault routine.

To clear the fault when		See this section
Condition	Fault Type
The execution of an instruction faults	4	Creating a Fault Routine for a Program

12	Rockwell Automation Publication 1756-PM014M-EN-P - September 2020

			Chapter 1	Major Faults
	To clear the fault when		See this section
	Condition	Fault Type
	Communication with an I/O module fails	3	Creating a Routine for the Controller
			Fault Handler
	Watchdog timer for a task expires	6
	A motion axis faults	11
	The controller powers up in Run or Remote Run	1	Creating a Routine for the Power-Up
	mode		Handler

See also

Create a fault routine for a program on page 13

Create a routine for the controller fault handler on page 15

Create a routine for the power-up handler on page 17

Create a fault routine for a program

Configure any routine as the fault routine for a program. The routine executes when a program fault occurs before the controller transitions to fault mode.

To create a fault routine for a program:

1.Open the project in the Logix Designer application.

2.In the Controller Organizer, right-click MainProgram and select

Add>New Routine.

3.On the New Routine dialog box, in Name, type the name of the routine.

Rockwell Automation Publication 1756-PM014M-EN-P - September 2020

13

Chapter 1

Major Faults

Change a fault routine assignment of a program

4.(optional) In Description, type a description of the routine.

5.In Type, use the default setting, Ladder Diagram.

6.In In Program or Phase, use the default setting, MainProgram.

Tip: If creating a fault routine for the Power-Up Handler or Controller Fault Handler, specify the program name of either program in In Program or Phase.

7.In Assignment, select Fault.

8.(optional) Select Open Routine to immediately open the ladder logic program.

9.Select OK.

See also

Create a routine for the controller fault handler on page 15 Create a routine for the power-up handler on page 17 Choose where to place the fault routine on page 12

Complete these steps to change the routine assigned as the fault routine.

To change a fault routine assignment of a program:

1. In the Controller Organizer, expand the MainTask.

14	Rockwell Automation Publication 1756-PM014M-EN-P - September 2020

Chapter 1

Major Faults

Create a routine for the controller fault handler

If there is already a fault routine, it appears in the MainProgram.

2.Right-click MainProgram and select Properties.

3.On the Program Properties - MainProgram dialog box, select the Configuration tab.

4.In Fault, choose the routine to be the program’s fault routine.

5.Select OK.

The program specified in step 4 is now indicated as the fault routine in the MainProgram.

See also

Create a fault routine for a program on page 13

Use these steps to create a fault routine to operate as the controller fault handler. Program tags are automatically created during this process.

IMPORTANT When programming the fault handler, remember that any instruction that is skipped as part of the fault-handling program does not run when the main tasks and associated programs run.

For example, if the fault handler skips a JSR instruction that is causing a major fault, then that JSR instruction, including all of the programming within the subroutine, does not run.

When an instruction generates an error due to a fault (for example, a COP with an indirect addressing programming error), the instruction is skipped and does not run. This occurs with all instructions.

Rockwell Automation Publication 1756-PM014M-EN-P - September 2020

15

Chapter 1

Major Faults

To create a routine for the controller fault handler:

1.In the Controller Organizer, right-click Controller Fault Handler and select New Program.

2.On the New Program dialog box, in Name, type a program name. Verify that Schedule in is set to Controller Fault Handler.

3.Select OK.

4.In the Controller Organizer, right-click the program created in step 2 and select Add>New Routine.

5.On the New Routine dialog box, in Name, type a name for the routine.

6.In Type, choose the type of routine to create. The default is Ladder Diagram.

7.In Assignment, use the default setting, Main.

Tip: Even though Fault is an option in the Assignment, assigning the routine as a fault routine within the Controller Fault Handler is not necessary.

8. Select OK.

16	Rockwell Automation Publication 1756-PM014M-EN-P - September 2020

Chapter 1

Major Faults

Create a routine for the power-up handler

The fault routine is created in the Controller Fault Handler program.

9. Double-click the fault routine to edit it.

See also

Recover from a major fault on page 9

Fault handling during prescan and postscan on page 11

The Power-Up Handler is an optional task that executes when the controller powers up in Run or Remote Run modes.

	To		Do this
	Prevent the controller from returning to Run or		Leave the routine for the Power-Up Handler empty. When
	Remote mode		power restored, a major fault (type 1, code 1) occurs and
			the controller enters the faulted state.
	Direct the controller to take specific actions,		In the Power-Up Handler fault routine, complete these
	then resume normal operation when power		steps.
	restored		1. Clear the major fault (type 1, code 1).
			2. Run the appropriate logic for the specific actions
			required.
	IMPORTANT	Do not use fault routines to continually clear all faults on the controller. Program the
		fault routine to be selective in the types and number of faults cleared.
	IMPORTANT	When an instruction generates an error due to a fault (for example, a COP with an
		indirect addressing programming error), the routine skips the instruction and the
		instruction does not run. This occurs with all instructions.

Rockwell Automation Publication 1756-PM014M-EN-P - September 2020

17