GuardLogix Controller Systems Safety Reference Manual, 1756

GuardLogix Controller Systems Safety Reference Manual, 1756
Safety Reference Manual
GuardLogix Controller Systems
Catalog Numbers 1756-L61S, 1756-L62S, 1756-L63S, 1756-L71S, 1756-L72S, 1756-L73S, 1756-L73SXT, 1756-LSP, 1756-L7SP,
1756-L7SPXT, 1768-L43S, 1768-L45S
Important User Information
Solid-state equipment has operational characteristics differing from those of electromechanical equipment. Safety
Guidelines for the Application, Installation and Maintenance of Solid State Controls (publication SGI-1.1 available from
your local Rockwell Automation sales office or online at http://www.rockwellautomation.com/literature/) describes some
important differences between solid-state equipment and hard-wired electromechanical devices. Because of this difference,
and also because of the wide variety of uses for solid-state equipment, all persons responsible for applying this equipment
must satisfy themselves that each intended application of this equipment is acceptable.
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.
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.
IMPORTANT
Identifies information that is critical for successful application and understanding of the product.
Rockwell Automation, Allen-Bradley, TechConnect, ControlLogix, GuardLogix, CompactLogix, CompactBlock Guard I/O, ArmorBlock Guard I/O, POINT Guard I/O, Guard I/O, FLEX I/O, SmartGuard, ControlLogixXT, ControlFLASH, Logix5000, SLC, RSLogix 5000, and FactoryTalk Security are trademarks of Rockwell Automation, Inc.
Trademarks not belonging to Rockwell Automation are property of their respective companies.
Summary of Changes
This manual contains new and updated information. Changes throughout this
revision are marked by change bars, as shown to the right of this paragraph.
New and Updated
Information
This table contains the changes made to this revision.
Topic
Page
Added 1756-L71S to list of GuardLogix safety controllers
14
Corrected memory size on 1756-L73SXT controllers
14
Edits were made to the information in Chapter 6, Safety Application Development
• Basics of Application Development and Testing
50
• Test the Application Program
53
• Generate the Safety Task Signature
53
• Confirm the Project
55
• Lock the GuardLogix Controller
56
• Downloading the Safety Application Program
57
• Performing Offline Edits and Performing Online Edits
60
Added information on modification impact testing
60
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
3
Summary of Changes
Notes:
4
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Table of Contents
Preface
Understanding Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Additional Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Chapter 1
Safety Integrity Level (SIL) Concept
SIL 3 Certification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Functional Verification Tests. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
GuardLogix Architecture for SIL 3 Applications . . . . . . . . . . . . . . . . . . . .
GuardLogix System Components. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
GuardLogix Certifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
GuardLogix PFD and PFH Specifications . . . . . . . . . . . . . . . . . . . . . . . . . .
Safety Integrity Level (SIL) Compliance Distribution and Weight. . . .
System Reaction Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Safety Task Reaction Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Safety Task Period and Safety Task Watchdog . . . . . . . . . . . . . . . . . .
Contact Information if Device Failure Occurs . . . . . . . . . . . . . . . . . . . . . .
11
12
13
14
16
16
17
18
18
19
19
Chapter 2
GuardLogix Controller System
1756 GuardLogix Controller Hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Primary Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Safety Partner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Chassis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1768 Compact GuardLogix Controller Hardware . . . . . . . . . . . . . . . . . .
CIP Safety Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Safety I/O . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Communication Bridges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Programming Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
21
22
22
22
22
23
23
23
24
26
Chapter 3
CIP Safety I/O for the GuardLogix
Control System
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Typical Safety Functions of CIP Safety I/O Modules . . . . . . . . . . . . . . . .
Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Status Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Status Indicators. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
On- or Off-delay Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Reaction Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Safety Considerations for CIP Safety I/O Modules. . . . . . . . . . . . . . . . . .
Ownership . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Safety I/O Configuration Signature . . . . . . . . . . . . . . . . . . . . . . . . . . . .
I/O Module Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
27
27
28
28
28
28
28
29
29
29
29
5
Table of Contents
Chapter 4
CIP Safety and the Safety Network
Number
Routable CIP Safety Control System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Unique Node Reference. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Safety Network Number . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Considerations for Assigning the Safety Network Number (SNN) . . .
Safety Network Number (SNN) for Safety Consumed Tags. . . . . .
Safety Network Number (SNN) for Out-of-box Modules. . . . . . . .
Safety Network Number (SNN) for Safety Module with a
Different Configuration Owner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Safety Network Number (SNN) When Copying a Safety Project .
33
34
34
35
35
36
36
36
Chapter 5
Characteristics of Safety Tags, the
Safety Task, and Safety Programs
Differentiate Between Standard and Safety . . . . . . . . . . . . . . . . . . . . . . . . .
SIL 2 Safety Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SIL 2 Safety Control in the Safety Task. . . . . . . . . . . . . . . . . . . . . . . . .
SIL 2 Safety Control in Standard Tasks (1756 GuardLogix
controllers only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SIL 3 Safety–the Safety Task . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Safety Task Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Safety Task Execution Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Use of Human-to-machine Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Accessing Safety-related Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Safety Programs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Safety Routines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Safety Tags . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Standard Tags in Safety Routines (tag mapping). . . . . . . . . . . . . . . . .
Additional Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
37
38
38
40
41
41
42
43
43
44
45
45
46
47
48
Chapter 6
Safety Application Development
6
Safety Concept Assumptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Basics of Application Development and Testing . . . . . . . . . . . . . . . . . . . .
Commissioning Life Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Specification of the Control Function . . . . . . . . . . . . . . . . . . . . . . . . . .
Create the Project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Test the Application Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Generate the Safety Task Signature . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Project Verification Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Confirm the Project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Safety Validation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Lock the GuardLogix Controller. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Downloading the Safety Application Program . . . . . . . . . . . . . . . . . . . . . .
Uploading the Safety Application Program . . . . . . . . . . . . . . . . . . . . . . . . .
Online Editing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Storing and Loading a Project from Nonvolatile Memory . . . . . . . . . . . .
Force Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
49
50
51
52
53
53
53
54
55
56
56
57
57
57
58
58
Table of Contents
Inhibit a Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Editing Your Safety Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Performing Offline Edits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Performing Online Edits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Modification Impact Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
58
59
60
60
60
Chapter 7
Monitor Status and Handle Faults
Monitoring System Status. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CONNECTION_STATUS Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input and Output Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
I/O Module Connection Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
De-energize to Trip System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Get System Value (GSV) and Set System Value (SSV)
Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
GuardLogix System Faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Nonrecoverable Controller Faults. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Nonrecoverable Safety Faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Recoverable Faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
63
63
64
64
65
65
66
66
66
67
Appendix A
Safety Instructions
Safety Application Instructions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Metal Form Safety Application Instructions . . . . . . . . . . . . . . . . . . . . . . . .
Safety Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Additional Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
69
70
71
72
Appendix B
Safety Add-On Instructions
Creating and Using a Safety Add-On Instruction . . . . . . . . . . . . . . . . . . .
Create Add-On Instruction Test Project . . . . . . . . . . . . . . . . . . . . . . .
Create a Safety Add-On Instruction. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Generate Instruction Signature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Download and Generate Safety Instruction Signature . . . . . . . . . . .
SIL 3 Add-On Instruction Qualification Test. . . . . . . . . . . . . . . . . . .
Confirm the Project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Safety Validate Add-On Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . .
Create Signature History Entry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Export and Import the Safety Add-On Instruction . . . . . . . . . . . . . .
Verify Safety Add-On Instruction Signatures . . . . . . . . . . . . . . . . . . .
Test the Application Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Project Verification Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Safety Validate Project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Additional Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
73
75
75
75
76
76
76
76
77
77
77
77
78
78
78
7
Table of Contents
Appendix C
Reaction Times
System Reaction Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Logix System Reaction Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Simple Input-logic-output Chain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Logic Chain Using Produced/Consumed Safety Tags. . . . . . . . . . . .
Factors Affecting Logix Reaction-time Components . . . . . . . . . . . . . . . .
Accessing Input Module Delay Time Settings . . . . . . . . . . . . . . . . . . .
Accessing Input and Output Safety Connection Reaction Time
Limit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Configuring the Safety Task Period and Watchdog . . . . . . . . . . . . . .
Accessing Produced/Consumed Tag Data . . . . . . . . . . . . . . . . . . . . . .
Additional Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
79
79
80
81
82
82
83
84
85
86
Appendix D
Checklists for GuardLogix Safety
Applications
Checklist for GuardLogix Controller System . . . . . . . . . . . . . . . . . . . . . . .
Checklist for Safety Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Checklist for Safety Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Checklist for Developing a Safety Application Program. . . . . . . . . . . . . .
88
89
90
91
Appendix E
GuardLogix Systems Safety Data
PFD Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
PFH Values. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
Appendix F
RSLogix 5000 Software, Version 14
and Later, Safety Application
Instructions
De-energize to Trip System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
Use Connection Status Data to Initiate a Fault Programmatically . . . . 95
Appendix G
Using 1794 FLEX I/O Modules and
1756 SIL 2 Inputs and Outputs with
1756 GuardLogix Controllers to
Comply with EN 50156
SIL 2 Dual-channel Inputs (standard side of 1756 GuardLogix
controllers) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SIL 2 Outputs Using SIL 3 Guard I/O Output Modules . . . . . . . . . . .
SIL 2 Outputs Using 1756 or 1794 SIL 2 Output Modules . . . . . . . . .
Safety Functions within the 1756 GuardLogix Safety Task. . . . . . . . . .
Glossary
Index
8
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
101
103
103
104
Preface
Topic
Page
Understanding Terminology
9
Additional Resources
10
This manual is intended to describe the GuardLogix controller system, which is
type-approved and certified for use in safety applications up to and including
SIL CL 3 according to IEC 61508 and IEC 62061, safety applications up to and
including Performance Level PLe (Category 4) according to ISO 13849-1.
This publication covers both 1756 and 1768 GuardLogix controller systems.
When ‘GuardLogix controllers’ is used alone in this publication, it refers to both
1756 and 1768 GuardLogix controllers. Information specific to one controller
type will include the bulletin number, 1756 or 1768.
Use this manual if you are responsible for the development, operation, or
maintenance of a GuardLogix controller-based safety system. You must read and
understand the safety concepts and requirements presented in this manual prior
to operating a GuardLogix controller-based safety system.
The following table defines terms used in this manual.
Understanding Terminology
Table 1 - Terms and Definitions
Abbreviation
Full Term
Definition
1oo2
One out of Two
Identifies the programmable electronic controller architecture.
CIP
Common Industrial Protocol
An industrial communication protocol used by Logix 5000-based automation systems on Ethernet,
ControlNet, and DeviceNet communication networks.
CIP Safety
Common Industrial Protocol – Safety
Certified
SIL 3 -rated version of CIP.
DC
Diagnostic Coverage
The ratio of the detected failure rate to the total failure rate.
EN
European Norm.
The official European Standard.
GSV
Get System Value
A ladder logic instruction that retrieves specified controller status information and places it in a destination
tag.
PC
Personal Computer
Computer used to interface with, and control, a Logix-based system via RSLogix 5000 programming
software.
PFD
Probability of Failure on Demand
The average probability of a system to fail to perform its design function on demand.
PFH
Probability of Failure per Hour
The probability of a system to have a dangerous failure occur per hour.
PL
Performance Level
ISO 13849-1 safety rating.
SNN
Safety Network Number
A unique number that identifies a section of a safety network.
SSV
Set System Value
A ladder logic instruction that sets controller system data.
--
Standard
Any object, task, tag, program, or component in your project that is not a safety-related item (that is,
standard controller refers generically to a ControlLogix® or CompactLogix™ controller).
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
9
Preface
These documents contain additional information concerning related products
from Rockwell Automation.
Additional Resources
Resource
Description
GuardLogix Controllers User Manual, publication 1756-UM020
Provides information on installing, configuring, and programming the GuardLogix system
CompactLogix Controllers Installation Instructions, publication 1768-IN004 Provides information on installing Compact GuardLogix controllers
1768 Compact GuardLogix Controllers User Manual, publication
1768-UM002
Details how to configure, program, and operate a 1768 CompactLogix system, and provides technical
specifications
GuardLogix Safety Application Instruction Set Reference Manual,
publication 1756-RM095
Provides information on the GuardLogix Safety Application instruction set
Guard I/O DeviceNet Safety Modules User Manual, publication
1791DS-UM001
Provides information on using Guard I/O DeviceNet Safety modules
Guard I/O EtherNet/IP Safety Modules User Manual, publication
1791ES-UM001
Provides information on using Guard I/O EtherNet/IP Safety modules
POINT Guard I/O Safety Modules User Manual, publication 1734-UM013
Provides information on installing and operating POINT Guard I/O modules
Using ControlLogix in SIL 2 Applications Safety Reference Manual,
publication 1756-RM001
Describes requirements for using ControlLogix controllers, and GuardLogix standard task, in SIL 2 safety
control applications
Logix5000 General Instruction Set Reference Manual, publication
1756-RM003
Provides information on the Logix5000™ Instruction Set
Logix Common Procedures Programming Manual, publication
1756-PM001
Provides information on programming Logix5000 controllers, including managing project files,
organizing tags, programming and testing routines, and handling faults
Logix5000 Controllers Add-On Instructions Programming Manual,
publication 1756-PM010
Provides information on using creating and using standard and safety Add-On Instructions in Logix
applications
ControlLogix System User Manual, publication 1756-UM001
Provides information on using ControlLogix controllers in non-safety applications
DeviceNet Modules in Logix5000 Control Systems User Manual, publication
DNET-UM004
Provides information on using the 1756-DNB module in a Logix5000 control system
EtherNet/IP Modules in Logix5000 Control Systems User Manual,
publication ENET-UM001
Provides information on using the 1756-ENBT module in a Logix5000 control system
ControlNet Modules in Logix5000 Control Systems User Manual,
publication CNET-UM001
Provides information on using the 1756-CNB module in Logix5000 control systems
Logix5000 Controllers Execution Time and Memory Use Reference Manual,
publication 1756-RM087
Provides information on estimating the execution time and memory use for instructions
Logix Import Export Reference Manual, publication 1756-RM084
Provides information on using the RSLogix 5000 Import/Export utility
Industrial Automation Wiring and Grounding Guidelines, publication
1770-4.1
Provides general guidelines for installing a Rockwell Automation industrial system.
Product Certifications website, http://www.ab.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 Allen-Bradley® distributor or
Rockwell Automation sales representative.
10
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Chapter
1
Safety Integrity Level (SIL) Concept
Topic
SIL 3 Certification
Page
SIL 3 Certification
11
Functional Verification Tests
12
GuardLogix Architecture for SIL 3 Applications
13
GuardLogix System Components
14
GuardLogix Certifications
16
GuardLogix PFD and PFH Specifications
16
Safety Integrity Level (SIL) Compliance Distribution and Weight
17
System Reaction Time
18
Safety Task Period and Safety Task Watchdog
19
Contact Information if Device Failure Occurs
19
1756 and 1768 GuardLogix controller systems are type-approved and certified
for use in safety applications up to and including SIL CL3 according to
IEC 61508 and IEC 62061, safety applications up to and including Performance
Level PLe (Category 4) according to ISO 13849-1. SIL requirements are based
on the standards current at the time of certification.
IMPORTANT
When the GuardLogix controller is in the Run or Programming mode and
you have not validated the application, you are responsible for maintaining
safe conditions.
In addition, the standard tasks within 1756 GuardLogix controllers can be used
either for standard applications or SIL 2 safety applications as described in the
Using ControlLogix in SIL 2 Applications Reference Manual, publication
1756-RM001. In either case, do not use SIL 2 or standard tasks and variables to
build up safety loops of a higher level. The safety task is the only task certified for
SIL 3 applications.
The standard task in 1768 Compact GuardLogix controllers may not be used for
SIL 2 safety applications.
RSLogix 5000 programming software is required to create programs for 1756
and 1768 GuardLogix controllers.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
11
Chapter 1
Safety Integrity Level (SIL) Concept
The TÜV Rheinland has approved GuardLogix controller systems for use in
safety-related applications up to SIL CL 3, in which the de-energized state is
considered to be the safe state. All of the examples related to I/O included in this
manual are based on achieving de-energization as the safe state for typical
Machine Safety and Emergency Shutdown (ESD) Systems.
IMPORTANT
The system user is responsible for:
• the setup, SIL rating, and validation of any sensors or actuators connected
to the GuardLogix system.
• project management and functional testing.
• access control to the safety system, including password handling.
• programming the application software and the device configurations in
accordance with the information in this safety reference manual and the
GuardLogix Controllers User Manual, publication
1756-UM020, or the 1768 Compact GuardLogix Controllers User Manual
publication 1768-UM002.
When applying Functional Safety, restrict access to qualified, authorized
personnel who are trained and experienced. The safety-lock function, with
passwords, is provided in RSLogix 5000 software.
For information on using the safety-lock feature, refer to the GuardLogix
Controllers User Manual, publication 1756-UM020, or the 1768 Compact
GuardLogix Controllers User Manual, publication 1768-UM002.
Functional Verification Tests
IEC 61508 requires the user to perform various functional verification tests of
the equipment used in the system. Functional verification tests are performed at
user-defined times. For example, functional verification test intervals can be once
a year, once every 15 years, or whatever time frame is appropriate.
GuardLogix controllers have a functional verification test interval of up to
20 years. Other components of the system, such as safety I/O modules, sensors,
and actuators may have shorter functional verification test intervals. The
controller should be included in the functional verification testing of the other
components in the safety system.
IMPORTANT
Your specific applications determine the time frame for the functional
verification test interval. However, this is mainly related to safety I/O
modules and field instrumentation.
For more information on the requirements of a functional verification test, see
Project Verification Test on pages 54 and 54.
12
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Safety Integrity Level (SIL) Concept
GuardLogix Architecture for
SIL 3 Applications
Chapter 1
The following illustration shows a typical SIL function, including:
• the overall safety function.
• the GuardLogix portion of the overall safety function.
• how other devices (for example, HMI) are connected, while operating
outside the function.
Figure 1 - Typical SIL Function
HMI
Read-only Access to Safety Tags
Programming Software
To Plant-wide Ethernet Network
Switch
Overall Safety Function
SIL 3 GuardLogix System
Actuator
1756-DNB
1756-ENBT
1756-LSP
1756-L6xS
CIP Safety
I/O Module
Sensor
DeviceNet Safety Network
CIP Safety
I/O Module
CIP Safety I/O Module on Ethernet
Network
Actuator
Sensor
CIP Safety
CIP Safety I/O Module on
Ethernet Network
Actuator
Compact GuardLogix Controller with 1768-ENBT Module
Sensor
SIL 3 Compact GuardLogix System
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
13
Chapter 1
Safety Integrity Level (SIL) Concept
The tables in this section list SIL 3-certified GuardLogix components for both
1756 and 1768 systems as well as non-SIL 3-certified components that may be
used with SIL 3 GuardLogix systems.
GuardLogix System
Components
For the most current list of GuardLogix controller and CIP Safety I/O modules
certified series and firmware revisions, see http://www.rockwellautomation.com/
products/certification/safety/. Firmware revisions are available at http://
support.rockwellautomation.com/ControlFLASH™/.
Table 2 - SIL 3-certified GuardLogix Components
Related Documentation(1)
Device Type
1756 GuardLogix
primary controller
(ControlLogix556xS)
Cat. No.
1756-L61S
Description
Controller with 4 MB standard, 1 MB safety memory
1756-L63S
Controller with 8 MB standard, 3.75 MB safety memory
1756-LSP
Safety partner
1756-L71S
Controller with 2 MB standard, 1 MB safety memory
1756-L72S
Controller with 4 MB standard, 2 MB safety memory
1756-L73S
Controller with 8 MB standard, 4 MB safety memory
1756-L73SXT
Controller (XT) with 8 MB standard, 4 MB safety memory
1756 GuardLogix
safety partner
(ControlLogix557SP)
1756-L7SP
Safety partner
1756-L7SPXT
Safety partner (XT)
1768 Compact GuardLogix
Controller
(CompactLogix4xS)
1768-L43S
Controller with support for two 1768 modules
1768-L45S
Controller with support for four 1768 modules
1756 GuardLogix
primary controller
(ControlLogix557xS)
CIP Safety I/O modules on
DeviceNet networks
CIP Safety I/O modules on
EtherNet/IP networks
N/A(2)
1756-UM020
N/A(2)
1756-UM020
1768-IN004
1768-UM002
1791DS-IN001
1791DS-IN002
1732DS-IN001
1791DS-UM001
For the most current list of certified series and firmware revisions, see the safety certificate at http:/
/www.rockwellautomation.com/products/certification/safety/
1791ES-IN001
N/A(2)
POINT Guard I/O modules
(1) These publications are available from Rockwell Automation by visiting http://www.rockwellautomation.com/literature.
(2) See user manual for installation instructions.
14
User Manual
Controller with 2 MB standard, 1 MB safety memory
1756-L62S
1756 GuardLogix
safety partner
(ControlLogix55SP)
Installation
Instructions
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
1791ES-UM001
1734-UM013
Safety Integrity Level (SIL) Concept
Chapter 1
Table 3 - Components Suitable for Use with 1756 GuardLogix Controller Safety Systems
Related Documentation(3)
Device Type
Chassis
Power supply
Communication
modules
Cat. No.
Memory cards
Series(1)
Revision(1)
B
N/A
N/A
1756-A4
1756-A7
1756-A10
1756-A13
1756-A17
4-slot chassis
7-slot chassis
10-slot chassis
13-slot chassis
17-slot chassis
1756-A4LXT
1756-A5XT
1756-A7XT
1756-A7LXT
4-slot XT chassis
5-slot XT chassis
7-slot XT chassis
7-slot XT chassis
B
1756-PA72
Power supply, AC
C
1756-PB72
Power supply, DC
C
1756-PA75
Power supply, AC
B
1756-PB75
Power supply, DC
B
1756-PAXT
XT power supply, AC
B
1756-PBXT
XT power supply, DC
B
1756-ENBT
1756-EN2T
1756-EN2F
1756-EN2TR
1756-EN3TR
EtherNet/IP bridge module
A
A
A
C
C
3.6
2.005
2.005
5.007
1756-EN2TXT
XT EtherNet/IP bridge module (copper)
C
5.007
1734-AENT
POINT I/O Ethernet Adapter
A
1756-DNB
DeviceNet bridge module
1756-CN2
ControlNet bridge module
1756-CN2R
1756-CN2RXT
Programming
software
Description
9324-xxxx
Installation
Instructions
User Manual
N/A
1756-IN005
N/A
N/A
ENET-IN002
ENET-UM001
3.001
1734-IN590
1734-UM011
A
6.2
DNET-IN001
DNET-UM004
A
12.1
ControlNet bridge module, redundant media
A
12.1
CNET-IN005
CNET-UM001
XT ControlNet bridge module, redundant media
B
20.020
N/A
Consult online
help.
N/A
N/A
RSLogix 5000 software for 1756-L6xS controllers
RSLogix 5000 software for 1756-L7xS and 1756-L73SXT controllers
1784-CF128
128MB CompactFlash Card for 1756-L6xS controllers
1784-SD1
1 GB Secure Digital (SD) Card for 1756-L7xS controllers
1784-SD2
2 GB Secure Digital (SD) Card for 1756-L7xS controllers
N/A
N/A
14(2)
20
N/A
(1) This version or later.
(2) RSLogix 5000 software, version 15, does not support GuardLogix safety controllers.
(3) These publications are available from Rockwell Automation by visiting http://www.rockwellautomation.com/literature.
Slots of a SIL 3 system chassis not used by the 1756 SIL 3 system may be
populated with other ControlLogix (1756) modules that are certified to the Low
Voltage and EMC Directives.
IMPORTANT
ControlLogix-XT™ system components are rated for extreme environmental
conditions only when used properly with other Logix-XT system components.
The use of ControlLogix-XT components with traditional ControlLogix or
GuardLogix system components nullifies extreme environment ratings.
To find the certificates for the ‘Programmable Control – ControlLogix Product
Family’ refer to http://www.rockwellautomation.com/products/certification/
ce/.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
15
Chapter 1
Safety Integrity Level (SIL) Concept
Table 4 - Components Suitable for Use With 1768 Compact GuardLogix Controller Safety Systems
Related Documentation(2)
Device Type
Power supply
Communication
modules
Cat. No.
Description
Series(1)
Revision(1)
Installation
Instructions
User Manual
1768-PA3
Power supply, AC
N/A
N/A
1768-PB3
Power supply, DC
N/A
N/A
1768-ENBT
EtherNet/IP bridge module
A
3.1.1
ENET-IN002
ENET-UM001
1734-AENT
POINT I/O Ethernet Adapter
A
3.001
1734-IN590
1734-UM011
N/A
1768-IN001
N/A
1734-AENTR
POINT I/O Ethernet Adapter
A
3.001
1734-IN040
1768-CNB
ControlNet bridge module
A
2.1.1
CNET-IN005
CNET-UM001
Programming
software
9324-xxxx
RSLogix 5000 software
N/A
18
N/A
Consult online help.
Memory Cards
1784-CF128
128 MB CompactFlash Card
N/A
N/A
N/A
N/A
(1) This revision or version or later.
(2) These publications are available from Rockwell Automation by visiting http://www.rockwellautomation.com/literature.
Expansion slots of a SIL 3 system bus that are not used by the 1768 SIL 3 system
may be populated with other CompactLogix (1768) modules that are certified to
the Low Voltage and EMC Directives. To find the certificates for the
‘Programmable Control – CompactLogix Product Family’, refer to
http://www.rockwellautomation.com/products/certification/ce/.
GuardLogix Certifications
The ControlLogix Controllers Technical Data, publication 1756-TD001 lists
the product specifications and the agency certifications for which the products
are approved. If a product has achieved agency certification, it is marked as such
on the product labeling. See the Product Certification link at http://
www.rockwellautomation.com/products/certification/ for Declarations of
Conformity, Certificates, and other certification details.
GuardLogix PFD and PFH
Specifications
Safety-related systems can be classified as operating in either a Low Demand
mode, or in a High Demand/Continuous mode. IEC 61508 quantifies this
classification by stating that the frequency of demands for operation of the safety
system is no greater than once per year in the Low Demand mode, or greater than
once per year in High Demand/Continuous mode.
The Safety Integrity Level (SIL) value for a Low Demand safety-related system is
directly related to order-of-magnitude ranges of its average probability of failure
to satisfactorily perform its safety function on demand or, simply, probability of
failure on demand (PFD). The SIL value for a High Demand/Continuous mode
safety-related system is directly related to the probability of a dangerous failure
occurring per hour (PFH).
16
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Safety Integrity Level (SIL) Concept
Chapter 1
PFD and PFH values are associated with each of the three primary elements
making up a safety-related system (the sensors, the logic element, and the
actuators). Within the logic element you also have input, processor, and output
elements.
For PFD and PFH values and functional verification (proof ) test intervals for
CIP Safety I/O modules, see Appendix E, GuardLogix Systems Safety Data.
Figure 2 - PFH Example
1791DS-IB12
Sensor
GuardLogix Controller
Logix5562S
LOOP 1
Logix55LSP
DeviceNet
EtherNet
1791DS-IB4XOX4
Actuator
Actuator
Sensor
LOOP 2
Sensor
1791DS-IB8XOB8
To determine the logic element PFH for each safety loop in the simple example
system shown in the PFH Example, sum the PFH values for each component in
the loop. The PFH Equations by Safety Loop table provides a simplified example
of PFH value calculations for each safety loop shown in the PFH Example
illustration.
Table 5 - PFH Equations by Safety Loop
For this loop
Sum the PFH values of these components
Total PFH for loop 1 =
1791DS-IB12 + GuardLogix controller + 1791DS-IB4XOX4
Total PFH for loop 2 =
1791DS-IB8XOB8 + GuardLogix controller + 1791DS-IB4XOX4
When calculating PFH values, you must take into account the specific
requirements of your application, including test intervals.
Safety Integrity Level (SIL)
Compliance Distribution and
Weight
The GuardLogix controller and I/O system may conservatively be assumed to
contribute 10% of the reliability burden. A SIL 3 system may need to incorporate
multiple inputs for critical sensors and input devices, as well as dual outputs
connected in series to dual actuators dependent on SIL assessments for the safety
related system.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
17
Chapter 1
Safety Integrity Level (SIL) Concept
Figure 3 - Reliability Burden
+V
10% of the PFD
40% of the
PFD
Sensor
Controller
Input
Module
Actuator
Output
Module
Sensor
Actuator
50% of the PFD
System Reaction Time
The system reaction time is the amount of time from a safety-related event as an
input to the system until the system sets corresponding outputs to their safe state.
Faults within the system can also have an effect upon the reaction time of the
system. The system reaction time is the sum of the following reaction times.
Sensor
Reaction
Time
+
Input
Reaction
Time
+
Safety Task
Reaction
Time
+
Output
Reaction
Time
+
Actuator
Reaction
Time
Each of the times listed above is variably dependent on factors such as the type of
I/O module and instructions used in the program.
Safety Task Reaction Time
The safety task reaction time is the worst-case delay from any input change
presented to the controller until the processed output is set by the output
producer. It is less than or equal to the sum of the safety task period and the safety
task watchdog.
18
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Safety Integrity Level (SIL) Concept
Chapter 1
Safety Task Period and Safety Task Watchdog
The safety task period is the interval at which the safety task executes.
The safety task watchdog time is the maximum permissible time for safety task
processing. If safety task processing time exceeds the safety task watchdog time, a
non-recoverable safety fault occurs in the controller and outputs transition to the
safe state (off ) automatically.
You define the safety task watchdog time, which must be less than or equal to the
safety task period.
The safety task watchdog time is set in the task properties window of
RSLogix 5000 software. This value can be modified online, regardless of
controller mode, but it cannot be changed when the controller is safety-locked or
once a safety task signature is created.
Contact Information if Device
Failure Occurs
If you experience a failure with any SIL 3-certified device, contact your local
Rockwell Automation distributor to initiate the following actions:
• You can return the device to Rockwell Automation so the failure is
appropriately logged for the catalog number affected and a record is made
of the failure.
• You can request a failure analysis (if necessary) to try to determine the
cause of the failure.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
19
Chapter 1
Safety Integrity Level (SIL) Concept
Notes:
20
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Chapter
2
GuardLogix Controller System
Topic
Page
1756 GuardLogix Controller Hardware
21
1768 Compact GuardLogix Controller Hardware
23
CIP Safety Protocol
23
Safety I/O
23
Communication Bridges
24
Programming Overview
26
For a brief listing of components suitable for use in Safety Integrity Level (SIL) 3
applications, see the table on page 14. For more detailed and up-to-date
information see http://www.rockwellautomation.com/products/certification/
safety/.
When installing a GuardLogix controller, follow the information in the
GuardLogix Controllers User Manual, publication 1756-UM020, or
CompactLogix Controllers Installation Instructions, publication 1768-IN004.
1756 GuardLogix Controller
Hardware
The 1756 GuardLogix controller consists of a primary controller
(ControlLogix 556xS or ControlLogix 557xS) and a safety partner
(ControlLogix 55SP or ControlLogix 557SP). These two modules work in a
1oo2 architecture to create the SIL 3-capable controller. They are described in
the following sections.
Both the primary controller and safety partner perform power-up and run-time
functional diagnostic tests of all safety-related components in the controller.
For details on status indicator operation, refer to the GuardLogix Controllers
User Manual, publication 1756-UM020.
IMPORTANT
Status indicators are not reliable indicators for safety functions. They should
be used only for general diagnostics during commissioning or
troubleshooting. Do not attempt to use status indicators to determine
operational status.
For a list of GuardLogix safety controller catalog numbers see Table 2 on page 14.
For a list of standard ControlLogix components suitable for safety applications,
see Table 3 on page 15.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
21
Chapter 2
GuardLogix Controller System
Primary Controller
The primary controller is the processor that performs standard and safety control
functions and communicates with the safety partner for safety-related functions
in the GuardLogix control system. The primary controller consists of a central
processor, I/O interface, and memory.
Safety Partner
To satisfy SIL 3 requirements, a safety partner must be installed in the slot
immediately to the right of the primary controller. The safety partner is a coprocessor that provides redundancy for safety-related functions in the system.
The safety partner is configured by the primary controller. Only a single
download of the user program to the primary controller is required. The safety
partner’s operating mode is controlled by the primary controller.
Chassis
The chassis provides the physical connections between modules and the 1756
GuardLogix system. Any failure, though unlikely, would be detected as a failure
by one or more of the active components of the system. Therefore, the chassis is
not relevant to the safety discussion.
GuardLogix-XT controllers must use a ControlLogix-XT chassis to achieve the
extreme environment rating.
Power Supplies
No extra configuration or wiring is required for SIL 3 operation of the
ControlLogix power supplies. Any failure would be detected as a failure by one or
more of the active components of the GuardLogix system. Therefore, the power
supply is not relevant to the safety discussion.
GuardLogix-XT controllers must use a ControlLogix-XT power supply to
achieve the extreme environment rating.
22
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
GuardLogix Controller System
1768 Compact GuardLogix
Controller Hardware
Chapter 2
The 1768 Compact GuardLogix controllers combine the primary and safety
partner controllers in a single controller hardware package to form a SIL 3
capable controller. Compact GuardLogix controllers feature a 1768 backplane
and a 1769 backplane to support standard 1769 I/O modules.
Table 6 - Compact GuardLogix Controller Catalog Numbers
Controller
Maximum 1768 Modules (local)
Maximum 1769 I/O Modules (local and
remote)
1768-L43S
2
16
1768-L45S
4
30
The 1768 Compact GuardLogix controller is powered by a 1768-PA3 or
1768-PB3 power supply. A 1769-ECR end cap is also required.
For a list of 1768 Compact GuardLogix safety controllers and standard
CompactLogix components suitable for safety applications, see GuardLogix
System Components on page 14.
CIP Safety Protocol
Safety-related communication between GuardLogix controllers takes place via
produced and consumed safety tags. These safety tags use the CIP Safety
protocol, which is designed to preserve data integrity during communication.
For more information on safety tags, see Chapter 5, Characteristics of Safety
Tags, the Safety Task, and Safety Programs.
Safety I/O
For information on CIP Safety I/O modules for use with GuardLogix
controllers, see Chapter 3.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
23
Chapter 2
GuardLogix Controller System
Communication Bridges
Table 7 lists the communication interface modules available to facilitate
communication over EtherNet/IP, DeviceNet, and ControlNet networks via the
CIP Safety protocol.
Table 7 - Communication Interface Modules by System
GuardLogix System
Communication Modules
1756
• 1756-ENBT, 1756-EN2T(R), 1756-EN2F, or 1756-EN3TR EtherNet/IP bridge
module
• 1734-AENT POINT I/O Ethernet Adapter
• 1756-DNB DeviceNet bridge module
• 1756-CN2 ControlNet bridge module
• 1756-CN2R Redundant ControlNet bridge module
1756 -XT
• 1756-EN2TXT XT EtherNet/IP bridge module (copper)
• 1756-CN2RXT Redundant XT ControlNet bridge module
1768
•
•
•
•
1768-ENBT
1734-AENT POINT I/O Ethernet Adapter
1768-CNB
1768-CNBR
Due to the design of the CIP Safety control system, CIP safety bridge
devices, like those listed in the table, are not required to be SIL 3-certified.
IMPORTANT
EtherNet/IP Network
Peer-to-peer safety communication between GuardLogix controllers is possible
via the EtherNet/IP network through the use of EtherNet/IP bridge modules.
An EtherNet/IP bridge module lets the GuardLogix controller control and
exchange safety data with CIP Safety I/O modules on an EtherNet/IP network.
Figure 4 - Peer-to-peer Communication via EtherNet/IP Bridge Modules and the EtherNet/IP
Network
Ethernet Switch
1756-ENBT
CIP Safety I/O Module
1756-DNB
CIP Safety I/O Module
1756-LSP
EtherNet/IP
Network
1756-L62S
1769-ECR
1768-L43S
1768-ENBT
1768-PB3
EtherNet/IP
Network
Controller B
Controller A
CIP Safety I/O Module
DeviceNet Network
CIP Safety I/O Module
TIP
Peer-to-peer safety communication between two 1756 GuardLogix
controllers in the same chassis is also possible via the backplane.
24
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
1756-LSP
1756-L62S
1756-LSP
1756-L62S
Backplane
GuardLogix Controller System
Chapter 2
DeviceNet Safety Network
DeviceNet bridge modules let the 1756 GuardLogix controller control and
exchange safety data with CIP Safety I/O modules on a DeviceNet network.
1756-DNB
1756-LSP
1756-L62S
Figure 5 - Communication via a DeviceNet Bridge Module
CIP Safety I/O Module
DeviceNet
Network
CIP Safety I/O Module
ControlNet Network
ControlNet bridge modules let the GuardLogix controller produce and consume
safety tags over ControlNet networks to other GuardLogix controllers or remote
CIP Safety I/O networks.
Figure 6 - Communication via a ControlNet Bridge Module
CIP Safety I/O Module
1756-CN2
1756-DNB
1756-IB16
1756-OB16
1769-ECR
1769-IA16
1768-L43S
1768-CNB
Controller A
1768-PB3
ControlNet
Network
Controller B
DeviceNet Network
CIP Safety I/O Module
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
25
Chapter 2
GuardLogix Controller System
Programming Overview
The programming software for the GuardLogix controller is RSLogix 5000
software.
RSLogix 5000 software is used to define the location, ownership, and
configuration of I/O modules and controllers. The software is also used to create,
test, and debug application logic. Initially, only relay ladder logic is supported in
the GuardLogix safety task.
See Appendix A for information on the set of logic instructions available for
safety applications.
Authorized personnel may change an application program, but only by using one
of the processes described in Editing Your Safety Application on page 59.
26
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Chapter
3
CIP Safety I/O for the GuardLogix Control System
Topic
Overview
Page
Overview
27
Typical Safety Functions of CIP Safety I/O Modules
27
Reaction Time
28
Safety Considerations for CIP Safety I/O Modules
29
Before operating a GuardLogix safety system containing CIP Safety I/O
modules, you must read, understand, and follow the installation, operation, and
safety information provided in the publications listed in the SIL 3-certified
GuardLogix Components tables on page 14.
CIP Safety I/O modules can be connected to safety input and output devices,
allowing these devices to be monitored and controlled by the GuardLogix
controller. For safety data, I/O communication is performed through safety
connections using the CIP Safety protocol; safety logic is processed in the
GuardLogix controller.
Typical Safety Functions of
CIP Safety I/O Modules
The following is treated as the safe state by CIP Safety I/O modules:
• Safety outputs: OFF
• Safety input data to controller: OFF
CIP Safety Network
Safety Status
Safety Output, OFF
Safety
Input
Data
The CIP Safety I/O modules should be used for applications that are in the safe
state when the safety output turns OFF.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
27
Chapter 3
CIP Safety I/O for the GuardLogix Control System
Diagnostics
CIP Safety I/O modules perform self-diagnostics when the power is turned ON
and periodically during operation. If a diagnostic failure is detected, safety input
data (to the controller) and local safety outputs are set to their safe state (OFF).
Status Data
In addition to safety input and output data, CIP Safety I/O modules support
status data to monitor module and I/O circuit health. Refer to your module’s
product documentation for specific product capabilities.
Status Indicators
The CIP Safety I/O modules include status indicators. For details on status
indicator operation, refer to the product documentation for your specific
module.
On- or Off-delay Function
Some CIP Safety I/O modules may support On-delay and Off-delay functions
for input signals. Depending upon your application, you may need to include
Off-delay, On-delay, or both when calculating system reaction time.
See Appendix C for information on system reaction time.
Reaction Time
The input reaction time is the time from when the signal changes on an input
terminal to when safety data is sent to the GuardLogix controller.
The output reaction time is the time from when safety data is received from the
GuardLogix controller to when the output terminal changes state.
For information on determining the input and output reaction times, refer to the
product documentation for your specific CIP Safety I/O module.
See Appendix C for information on calculating the system reaction time.
28
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
CIP Safety I/O for the GuardLogix Control System
Safety Considerations for CIP
Safety I/O Modules
Chapter 3
You must commission all devices with a node or IP address and communication
rate, if necessary, before their installation on a safety network.
Ownership
Each CIP Safety I/O module in a GuardLogix system is owned by one
GuardLogix controller. Multiple GuardLogix controllers and multiple CIP
Safety I/O modules can be used without restrictions in chassis or on networks as
needed. When a controller owns an I/O module, it stores the module’s
configuration data, as defined by the user. This controls how the modules operate
in the system.
From a control standpoint, safety output modules can only be controlled by one
controller. Each safety input module is also owned by a single controller;
however, safety input data can be shared (consumed) by multiple GuardLogix
controllers.
Safety I/O Configuration Signature
The configuration signature defines the module’s configuration. It can be read
and monitored. The configuration signature is used to uniquely identify a
module’s configuration. When using a GuardLogix controller, you do not have to
monitor this signature. It is monitored automatically by the GuardLogix
controller.
I/O Module Replacement
The replacement of safety devices requires that the replacement device be
configured properly and that the replacement device’s operation be user-verified.
ATTENTION: During replacement or functional testing of a module, the safety
of the system must not rely on any portion of the affected module.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
29
Chapter 3
CIP Safety I/O for the GuardLogix Control System
Two options for I/O module replacement are available on the Safety tab of the
Controller Properties dialog box in RSLogix 5000 software:
• Configure Only When No Safety Signature Exists
• Configure Always
Figure 7 - Safety I/O Replacement Options
Configure Only When No Safety Signature Exists
This setting instructs the GuardLogix controller to configure a safety module
only when the safety task does not have a safety task signature, and the
replacement module is in an out-of-box condition, meaning that a safety network
number does not exist in the safety module.
If the safety task has a safety task signature, the GuardLogix controller only
configures the replacement CIP Safety I/O module if the following is true:
• The module already has the correct safety network number.
• The module electronic keying is correct.
• The node or IP address is correct.
30
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
CIP Safety I/O for the GuardLogix Control System
Chapter 3
Configure Always
The GuardLogix controller will always attempt to configure a replacement CIP
Safety I/O module if the module is in an out-of-box condition, meaning that a
safety network number does not exist in the replacement safety module, and the
node number and I/O module keying matches the controller’s configuration.
ATTENTION: Enable the Configure Always feature only if the entire routable CIP
Safety control system is not being relied on to maintain SIL 3 behavior during
the replacement and functional testing of a module.
If other parts of the CIP Safety control system are being relied upon to maintain SIL
3, make sure that the controller’s Configure Always feature is disabled.
It is your responsibility to implement a process to make sure proper safety
functionality is maintained during device replacement.
ATTENTION: Do not place any modules in the out-of-box condition on any CIP
Safety network when the Configure Always feature is enabled, except while
following the module replacement procedure in the GuardLogix Controllers User
Manual, publication 1756-UM020, or the 1768 Compact GuardLogix Controllers
User Manual, publication 1768-UM002.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
31
Chapter 3
CIP Safety I/O for the GuardLogix Control System
Notes:
32
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Chapter
4
CIP Safety and the Safety Network Number
Topic
Page
Routable CIP Safety Control System
33
Considerations for Assigning the Safety Network Number (SNN)
35
To understand the safety requirements of a CIP Safety control system, including
the safety network number (SNN), you must first understand how
communication is routable in CIP control systems. The CIP Safety control
system represents a set of interconnected CIP Safety devices. The routable system
represents the extent of potential mis-routing of packets from an originator to a
target within the CIP Safety control system. The system is isolated such that
there are no other connections into the system. For example, because the system
below cannot be interconnected to another CIP Safety system through a larger,
plant-wide Ethernet backbone, it illustrates the extent of a routable CIP Safety
system.
Routable CIP Safety Control
System
Figure 8 - CIP Safety System Example
CIP Safety I/O
CIP Safety I/O
CIP Safety I/O
CIP Safety I/O
CIP Safety I/O
CIP Safety I/O
1756-ENBT
1756-DNB
1756-IB16
1756-OB16
1769-ECR
1768-L43S
1768-ENBT
1768-ENBT
Switch
1768-PB3
1756-ENBT
1756-DNB
Switch
1756-LSP
1756-L62S
Router/
Firewall(1)
SmartGuard™
CIP Safety I/O
CIP Safety I/O
(1) The router or firewall is set up to limit traffic.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
33
Chapter 4
CIP Safety and the Safety Network Number
Unique Node Reference
The CIP Safety protocol is an end-node to end-node safety protocol. The CIP
Safety protocol allows the routing of CIP Safety messages to and from CIP Safety
devices through non-certified bridges, switches, and routers.
To prevent errors in non-certified bridges, switches, or routers from becoming
dangerous, each end node within a routable CIP Safety control system must have
a unique node reference. The unique node reference is a combination of a safety
network number (SNN) and the node address of the node.
Safety Network Number
The safety network number (SNN) is assigned by software or by the user. Each
CIP Safety network that contains Safety I/O nodes must have at least one unique
SNN. Each ControlBus chassis that contains one or more safety devices must
have at least one unique SNN. Safety network numbers assigned to each safety
network or network subnet must be unique.
More than one SNN can be assigned to a CIP Safety subnet or a ControlBus
chassis that contains more than one safety device. However, for simplicity,
we recommend that each CIP Safety subnet have one, and only one, unique
SNN. This is also the case for each ControlBus chassis.
TIP
Figure 9 - CIP Safety Example with More Than One SNN
CIP Safety I/O
1756-ENBT
1756-DNB
1756-IB16
1756-OB16
1769-ECR
1768-L43S
1768-ENBT
SNN_3
SNN_1
CIP Safety I/O
1768-ENBT
Switch
1768-PB3
1756-ENBT
1756-DNB
Switch
1756-LSP
1756-L62S
Router/
Firewall
SNN_5
CIP Safety I/O
SmartGuard
CIP Safety I/O
CIP Safety I/O
SNN_7
CIP Safety I/O
SNN_2
CIP Safety I/O
SNN_4
CIP Safety I/O
SNN_6
Each CIP Safety device must be configured with an SNN. Any device that
originates a safety connection to another safety device must be configured with
the SNN of the target device. If the CIP Safety system is in the start-up process
prior to the functional safety testing of the system, the originating device may be
used to set the unique node reference into the device.
The SNN used by the system is a 6-byte hexadecimal number. The SNN can be
set and viewed in one of two formats: time-based or manual. When the time34
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
CIP Safety and the Safety Network Number
Chapter 4
based format is selected, the SNN represents a localized date and time. When the
manual format is selected, the SNN represents a network type and a decimal
value from 1…9999.
Figure 10 - SNN Formats
The assignment of a time-based SNN is automatic when creating a new
GuardLogix safety controller project and adding new Safety I/O modules.
Manual manipulation of an SNN is required in the following situations:
• If safety consumed tags are used.
• If the project will consume safety input data from a module whose
configuration is owned by some other safety device
• If a safety project is copied to a different hardware installation within the
same routable CIP Safety system
IMPORTANT
Considerations for Assigning
the Safety Network Number
(SNN)
If you assign an SNN manually, take care to make sure that system
expansion does not result in duplication of SNN and node address
combinations.
The assignment of the SNN is dependent upon factors including the
configuration of the controller or CIP Safety I/O module.
Safety Network Number (SNN) for Safety Consumed Tags
When a safety controller that contains produced safety tags is added to the I/O
Configuration tree, the SNN of the producing controller must be entered. The
SNN may be copied from the producing controller’s project and pasted into the
new controller being added to the I/O Configuration tree.
Refer to the GuardLogix Controllers User Manual, publication 1756-UM020, or
the 1768 Compact GuardLogix Controllers User Manual, publication
1768-UM002, for information on how to copy and paste an SNN.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
35
Chapter 4
CIP Safety and the Safety Network Number
Safety Network Number (SNN) for Out-of-box Modules
Out-of-box CIP Safety I/O modules do not have an SNN. The SNN is set when
a configuration is sent to the module by the GuardLogix controller that owns the
module.
IMPORTANT
To add a CIP Safety I/O module to a configured GuardLogix system (the SNN
is present in the GuardLogix controller), the replacement CIP Safety module
should have the correct SNN applied before it is added to the CIP Safety
network.
Safety Network Number (SNN) for Safety Module with a Different
Configuration Owner
When a CIP Safety I/O module is owned by a different GuardLogix controller
(controller B), and then is added to another GuardLogix project (controller A
project), RSLogix 5000 software assigns the SNN based on the current project.
Because the current project (controller A project) is not the true configuration
owner, you need to copy the original SNN (controller B project) into the
configuration in controller A’s project. This is easy to do with standard copy and
paste commands. The result is that the CIP Safety I/O module produces data to
two GuardLogix controllers at the same time. You can do this for a maximum of
16 controllers.
Refer to the GuardLogix Controllers User Manual, publication 1756-UM020, or
the 1768 Compact GuardLogix Controllers User Manual, publication
1768-UM002, for information on changing, copying, and pasting safety network
numbers.
Safety Network Number (SNN) When Copying a Safety Project
ATTENTION: If a safety project is copied for use in another project with different
hardware or in a different physical location, and the new project is within the
same routable CIP Safety system, every SNN must be changed in the second
system. SNN values must not be repeated.
Refer to the GuardLogix Controllers User Manual, publication
1756-UM020, or the 1768 Compact GuardLogix Controllers User Manual,
publication 1768-UM002, for information on changing the SNN.
36
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Chapter
5
Characteristics of Safety Tags, the Safety Task,
and Safety Programs
Topic
Differentiate Between
Standard and Safety
Page
Differentiate Between Standard and Safety
37
SIL 2 Safety Applications
38
SIL 3 Safety–the Safety Task
41
Use of Human-to-machine Interfaces
43
Safety Programs
45
Safety Routines
45
Safety Tags
46
Additional Resources
48
Because it is a Logix-series controller, both standard (non-safety-related) and
safety-related components can be used in the GuardLogix control system.
You can perform standard automation control from standard tasks within a
GuardLogix project. 1756 GuardLogix controllers provide the same
functionality as other 1756 ControlLogix series controllers. 1768 Compact
GuardLogix controllers provide the same functionality as other 1768-L4x
CompactLogix controllers. What differentiates 1756 and 1768 GuardLogix
controllers from standard controllers is that they provide a SIL 3-capable safety
task.
However, a logical and visible distinction is required between the standard and
safety-related portions of the application. RSLogix 5000 software provides this
differentiation via the safety task, safety programs, safety routines, safety tags, and
safety I/O modules. You can implement both SIL 2 and SIL 3 levels of safety
control with the safety task of the GuardLogix controller.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
37
Chapter 5
Characteristics of Safety Tags, the Safety Task, and Safety Programs
SIL 2 Safety Applications
You can perform SIL 2 safety control by using the 1756 or 1768 GuardLogix
controller’s safety task.
Because 1756 GuardLogix controllers are part of the ControlLogix series of
processors, you can perform SIL 2 safety control with a 1756 GuardLogix
controller by using standard tasks or the safety task. This capability provides
unique and versatile safety control options, as most applications have a higher
percentage of SIL 2 safety functions than SIL 3 safety functions.
SIL 2 Safety Control in the Safety Task
The 1756 and 1768 GuardLogix safety task can be used to provide SIL 2 as well
as SIL 3 safety functions. If SIL 3 safety functions need to be performed at the
same time as SIL 2 safety functions, you must fulfill the requirements defined in
the SIL 3 Safety–the Safety Task, Safety Programs, and Safety Routines sections
of this chapter, as well as the SIL 2 requirements listed in this section.
SIL 2 Safety Logic
From a GuardLogix safety control perspective, the biggest difference between
SIL 2 and SIL 3 safety-rated devices is that SIL 2 is generally single-channel,
while SIL 3 is typically dual-channel. When using Guard safety-rated I/O (red
modules), which is required in the safety task, SIL 2 safety inputs can be single
channel which can reduce complexity and the number of modules that are
necessary.
It is up to the safety system designer to properly implement all safety functions.
Consideration must be given to:
• field device selection (proper selection, identify and mitigate all device
faults)
• consider safety demand requirements (low IEC 61511 or high
ISO 13849)
• consider test intervals (diagnostics and proof testing needed to satisfy
application requirements)
• identify, and justify with proper documentation any fault exclusions that
are used
IMPORTANT
If a combination of SIL 2 and SIL 3 safety functions are used at the same
time within the safety task, you must prevent SIL 2 input signals from
directly controlling SIL 3 safety functions. This can be done by using specific
safety task programs or routines to separate SIL 2 and SIL 3 safety
functions.
Within the safety task, RSLogix 5000 software includes a set of safety-related
ladder-logic instructions. In addition to these safety-rated ladder logic
instructions, GuardLogix controllers feature application-specific SIL 3-rated
safety instructions. All of these logic instructions may be used in Cat 1…4 and
SIL 1…3 safety functions.
38
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Characteristics of Safety Tags, the Safety Task, and Safety Programs
Chapter 5
For SIL 2-only safety, a safety task signature is not required. However, if any
SIL 3 safety functions are used within the safety task, a safety task signature is
required.
Safety-locking the safety task once testing is completed is recommended for SIL 2
applications. Locking the safety task enables additional security features. You may
also use FactoryTalk Security® and RSLogix 5000 routine source protection to
limit access to safety-related logic.
For more information on generating a safety task signature and safety-locking the
safety task, refer to the GuardLogix Controllers User Manual, publication
1756-UM020, or the Compact GuardLogix Controllers User Manual,
publication 1768-UM002.
SIL 2 Safety Inputs
CompactBlock™ Guard I/O™ (1791-series), ArmorBlock® Guard I/O™ (1732series), and POINT Guard I/O (1734-series) safety input modules support
single-channel SIL 2 safety input circuits. Because these modules are also rated
for SIL 3 operation, mixing SIL 2 and SIL 3 circuits on the same module is
allowed, provided you follow these guidelines.
These two wiring examples show how to wire SIL 2 safety circuits to Guard I/O
safety input modules. These examples make use of onboard test sources (T0…Tx)
that are resident on all 1791 and 1732 safety input modules.
Figure 11 - Input Wiring
I0
I1
T0
T1
Guard I/O modules group inputs in pairs to facilitate Cat 3, Cat 4, and SIL 3
safety functions. For use in Cat 1, Cat 2, and SIL 2 safety functions, module
inputs should still be used in pairs as illustrated. Two SIL 2 safety functions are
shown wired to inputs I0 and I1 using test sources T0 and T1, respectively.
Figure 12 - Input Wiring in Pairs
I0
I1
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
T0
T1
39
Chapter 5
Characteristics of Safety Tags, the Safety Task, and Safety Programs
For Cat 1, Cat 2, and SIL 2 safety functions, the Guard I/O safety modules need
specific configurations within the GuardLogix project. In this example, inputs 0,
1, 6, 7, 8, 9, 10, and 11 are part of a CAT 1, 2 or SIL 2 safety function. Inputs 2
and 3, as well as 4 and 5 are part of a CAT 3, CAT 4, or SIL 3 safety function.
Figure 13 - Input Configuration
Field
Value
Type
Single
Discrepancy Time
N/A
Point Mode
Safety Pulse Test
Test Source
Set values based on how the field device is physically wired to the module. To make sure
the test source is properly enabled, open and view settings on the Test Output tab.
Input Delay Time
User input based on field device characteristics.
IMPORTANT
The onboard pulse test outputs (T0…Tx) are typically used with field
devices that have mechanical contacts. If a safety device that has electronic
outputs is used (feeding safety inputs), they must have the appropriate
safety ratings.
IMPORTANT
If you are using GuardLogix Safety Application Instructions, be sure to
configure your safety input modules as single, not equivalent or
complementary. These instructions provide all dual-channel functionality
necessary for PLd (Cat. 3) or PLe (Cat. 4) safety functions.
Refer to the GuardLogix Safety Application Instruction Set Reference
Manual, publication 1756-RM095.
SIL 2 Safety Control in Standard Tasks (1756 GuardLogix controllers
only)
Because of the quality and amount of diagnostics built into the 1756
ControlLogix series of controllers, you can perform SIL 2 safety functions from
within standard tasks. This is also true for 1756 GuardLogix controllers.
40
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Characteristics of Safety Tags, the Safety Task, and Safety Programs
Chapter 5
To perform SIL 2 safety control within a GuardLogix standard task, you must
abide by requirements defined in the Using ControlLogix in SIL 2 Applications
Safety Reference Manual, publication 1756-RM001.
IMPORTANT
SIL 3 Safety–the Safety Task
You may not use the standard task in a 1768 Compact GuardLogix controller
for SIL-2 safety applications.
Creation of a GuardLogix project automatically creates a single safety task. The
safety task has these additional characteristics:
• GuardLogix controllers are the only controllers that support the safety
task.
• The safety task cannot be deleted.
• GuardLogix controllers support a single safety task.
• Within the safety task, you can use multiple safety programs composed of
multiple safety routines.
• You cannot schedule or execute standard routines from within the safety
task.
The safety task is a periodic timed task with a user-selectable task priority and
watchdog. In most cases, it is the controller’s top priority and the user-defined
program watchdog must be set to accommodate fluctuations in the execution of
the safety task.
Safety Task Limitations
You specify both the safety task period and the safety task watchdog. The safety
task period is the period at which the safety task executes. The safety task
watchdog is the maximum time allowed from the start of safety task scheduled
execution to its completion.
For more information on the safety task watchdog, see Appendix C, Reaction
Times.
The safety task period is limited to a maximum of 500 ms and cannot be
modified online. Make sure that the safety task has enough time to finish before
it is triggered again. Safety task watchdog timeout, a non-recoverable safety fault
in the GuardLogix controller, occurs if the safety task is triggered while it is still
executing from the previous trigger.
See Chapter 7, Monitor Status and Handle Faults, for more information.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
41
Chapter 5
Characteristics of Safety Tags, the Safety Task, and Safety Programs
Safety Task Execution Details
The safety task executes in the same manner as standard periodic tasks, with the
following exceptions:
• The safety task does not begin executing until the primary controller and
safety partner have established their control partnership and the
coordinated system time (CST) is synchronized. However, standard tasks
begin executing as soon as the controller transitions to Run mode.
• Although the configurable range of the requested packet interval (RPI) for
safety inputs and safety consumed tags is 6…500 ms, safety input tags and
safety-consumed tags are updated only at the beginning of safety task
execution. This means that even though the I/O RPI can be faster than the
safety task period, the data does not change during safety task execution.
The data is read only once at the beginning of the safety task execution.
• Safety input values are frozen at the start of safety task execution. As a
result, timer-related instructions, such as TON and TOF, will not update
during a single safety task execution. They will keep accurate time from
one task execution to another, but the accumulated time will not change
during safety task execution.
ATTENTION: This behavior differs from standard Logix task execution,
but is similar to PLC or SLC™ behavior.
• For standard tags that are mapped to safety tags, the standard tag values are
copied into safety memory at the start of the safety task and do not change
during safety task execution.
• Safety output tag (output and produced) values are updated at the
conclusion of safety task execution.
42
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Characteristics of Safety Tags, the Safety Task, and Safety Programs
Chapter 5
• The safety task responds to mode changes (for example, Run to Program
or Program to Run) at timed intervals. As a result, the safety task may take
more than one task period, but always less than two, to make a mode
transition.
IMPORTANT
Use of Human-to-machine
Interfaces
While safety-unlocked and without a safety task signature, the controller
prevents simultaneous write access to safety memory from the safety task
and communication commands. As a result, the safety task can be held off
until a communication update completes. The time required for the update
varies by tag size. Therefore, safety connection and/or safety watchdog
timeouts could occur. (For example, if you make online edits when the safety
task rate is set to 1 ms, a safety watchdog timeout could occur.)
To compensate for the hold-off time due to a communication update, add 2
ms to the safety watchdog time.
When the controller is safety-locked or a safety task signature exists, the
situation described in this note cannot occur.
Follow these precautions and guidelines for using HMI devices in SIL-rated
GuardLogix systems.
Precautions
You must exercise precautions and implement specific techniques on HMI
devices. These precautions include, but are not restricted to the following:
• Limited access and security
• Specifications, testing, and validation
• Restrictions on data and access
• Limits on data and parameters
For more information on how HMI devices fit into a typical SIL loop, see
Figure 1 on page 13.
Use sound techniques in the application software within the HMI and controller.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
43
Chapter 5
Characteristics of Safety Tags, the Safety Task, and Safety Programs
Accessing Safety-related Systems
HMI- related functions consist of two primary activities: reading and writing
data.
Reading Parameters in Safety-related Systems
Reading data is unrestricted because reading doesn’t affect the behavior of the
safety system. However, the number, frequency, and size of the data being read
can impact controller availability. To avoid safety-related nuisance trips, use good
communication practices to limit the impact of communication processing on
the controller. Do not set read rates to the fastest rate possible.
Changing Parameters in SIL-rated Systems
A parameter change in a safety-related loop via an external (that is, outside the
safety loop) device (for example, an HMI) is allowed only with the following
restrictions:
• Only authorized, specially-trained personnel (operators) can change the
parameters in safety-related systems via HMIs.
• The operator who makes changes in a safety-related system via an HMI is
responsible for the effect of those changes on the safety loop.
• You must clearly document variables that are to be changed.
• You must use a clear, comprehensive, and explicit operator procedure to
make safety-related changes via an HMI.
• Changes can only be accepted in a safety-related system if the following
sequence of events occurs:
a. The new variable must be sent twice to two different tags; that is, both
values must not be written to with one command.
b. Safety-related code, executing in the controller, must check both tags
for equivalency and make sure they are within range (boundary checks).
c. Both new variables must be read back and displayed on the HMI
device.
d. Trained operators must visually check that both variables are the same
and are the correct value.
e. Trained operators must manually acknowledge that the values are
correct on the HMI screen that sends a command to the safety logic,
which allows the new values to be used in the safety function.
In every case, the operator must confirm the validity of the change before
they are accepted and applied in the safety loop.
• Test all changes as part of the safety validation procedure.
44
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Characteristics of Safety Tags, the Safety Task, and Safety Programs
Chapter 5
• Sufficiently document all safety-related changes made via the HMI,
including the following:
–
–
–
–
–
Authorization
Impact analysis
Execution
Test information
Revision information
• Changes to the safety-related system must comply with IEC 61511
standard on process safety, section 11.7.1 Operator Interface requirements.
• Changes to the safety-related system must comply with IEC 62061 for
machine safety.
• The developer must follow the same sound development techniques and
procedures used for other application software development, including the
verification and testing of the operator interface and its access to other
parts of the program. In the controller application software, set up a table
that is accessible by the HMI and limit access to required data points only.
• Similar to the controller program, the HMI software needs to be secured
and maintained for SIL-level compliance after the system has been
validated and tested.
Safety Programs
A safety program has all the attributes of a standard program, except that it can be
scheduled only in the safety task. A safety program may also define programscoped safety tags. A safety program may be scheduled or unscheduled.
A safety program can contain only safety components. All of the routines in a
safety program are safety routines. A safety program cannot contain standard
routines or standard tags.
Safety Routines
Safety routines have all the attributes of standard routines, except that they can
exist only in safety programs. One safety routine may be designated as the main
routine. Another safety routine may be designated as the fault routine. Only
safety-certified instructions may be used in safety routines.
For a listing of safety instructions, see Appendix A.
ATTENTION: To preserve SIL 3, you must make sure that your safety logic does
not attempt to read or write standard tags.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
45
Chapter 5
Characteristics of Safety Tags, the Safety Task, and Safety Programs
Safety Tags
The GuardLogix control system supports the use of both standard and safety tags
in the same project. However, the programming software operationally
differentiates standard tags from safety tags.
Safety tags have all the attributes of standard tags with the addition of
mechanisms to provide SIL 3 data integrity.
Table 8 - Valid Data Types for Safety Tags
• AUX_VALVE_CONTROL
• DINT
• MUTING_FOUR_SENSOR_BIDIR
• BOOL
• DIVERSE_INPUT
• MUTING_TWO_SENSOR_ASYM
• CAM_PROFILE
• EIGHT_POS_MODE_SELECTOR
• MUTING_TWO_SENSOR_SYM
• CAMSHAFT_MONITOR
• EMERGENCY_STOP
• MOTION_INSTRUCTION
• CB_CONTINUOUS_MODE
• ENABLE_PENDANT
• PHASE
• CB_CRANKSHAFT_POS_MONITOR
• EXT_ROUTINE_CONTROL
• PHASE_INSTRUCTION
• CB_INCH_MODE
• EXT_ROUTINE_PARAMETERS
• REAL(1)
• CB_SINGLE_STROKE_MODE
• FBD_BIT_FIELD_DISTRIBUTE
• REDUNDANT_INPUT
• CONFIGURABLE_ROUT
• FBD_CONVERT
• REDUNDANT_OUTPUT
• CONNECTION_STATUS
• FBD_COUNTER
• SAFETY_MAT
• CONTROL
• FBD_LOGICAL
• SERIAL_PORT_CONTROL
• COUNTER
• FBD_MASK_EQUAL
• SFC_ACTION
• DCA_INPUT
• FBD_MASKED_MOVE
• SFC_STEP
• DCI_MONITOR
• FBD_TIMER
• SFC_STOP
• DCI_START
• FIVE_POS_MODE_SELECTOR
• SINT
• DCI_STOP
• INT
• STRING
• DCI_STOP_TEST
• LIGHT_CURTAIN
• THRS_ENHANCED
• DCI_STOP_TEST_LOCK
• MAIN_VALVE_CONTROL
• TIMER
• DCI_STOP_TEST_MUTE
• MANUAL_VALVE_CONTROL
• TWO_HAND_RUN_STATION
(1) Safety tags created by using the REAL data type are valid only on 1756-L7xS safety controllers.
RSLogix 5000 software prevents the direct creation of invalid tags in a safety
program. In the event that invalid tags are imported, they cannot be verified.
In safety programs on 1756-L6xS and 1768-L4xS controllers, RSLogix 5000
software also prevents the following:
• The creation of a safety tag using a structured type (user-defined, Add-On
defined, predefined) when they contain one or more members of the
REAL data type, including nested structures.
• The modification of a user-defined, or Add-On defined type that would
cause an invalid data type to be included when the user-defined or AddOn defined type is already referenced directly or indirectly by a safety tag.
• Invalid tags created by using with the New Tag or Tag Properties dialog
box.
IMPORTANT
46
Aliasing between standard and safety tags is prohibited in safety
applications.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Characteristics of Safety Tags, the Safety Task, and Safety Programs
Chapter 5
Tags classified as safety tags are either controller-scoped or program-scoped.
Controller-scoped safety tags can be read by either standard or safety logic or
other communication devices, but can only be written to by safety logic or
another GuardLogix safety controller. Program-scoped safety tags are accessible
only by local safety routines. These are routines that reside within the safety
program.
Tags associated with Safety I/O and produced or consumed safety data must be
controller-scoped safety tags.
Any controller-scoped safety tag is readable by any standard routine, but
the update rate is based on the execution of the safety task. This means
that safety tags are updated at the safety task periodic rate, which is
different from standard tag behavior.
IMPORTANT
Standard Tags in Safety Routines (tag mapping)
Controller-scoped standard tags can be mapped into safety tags, providing you
with a mechanism to synchronize standard and safety actions.
ATTENTION: When using standard data in a safety routine, you are responsible
for providing a reliable means of ensuring that the data is used in an appropriate
manner. Using standard data in a safety tag does not make it safety data. You
must not directly control a safety output with standard tag data.
This example illustrates how to qualify the standard data with safety data.
Figure 14 - Qualify Standard Data with Safety Data
MappedBooleanTag
LatchOneShot
Node30ComboModule:I.Pt07Data
Node30ComboModule:O.Pt03Data
ONS
Node30ComboModule:O.Pt03Data
Safety Input Qualifier for Mapped Tag
Latch circuit to prevent automatic restart if the standard input
(MappedTag) is failed in a ‘stuck at 1’ state.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Safety Output
47
Chapter 5
Characteristics of Safety Tags, the Safety Task, and Safety Programs
Additional Resources
48
These documents contain addition information about GuardLogix controllers.
Resource
Description
Logix5000 Controllers Design Considerations Reference
Manual, publication 1756-RM094
Provides information on managing tasks and the effects
of task execution and timing on user data
GuardLogix Controllers User Manual, publication 1756UM020
Contains information on how to map tags
1768 Compact GuardLogix Controllers User Manual,
publication 1768-UM002
Contains information on how to map tags
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Chapter
6
Safety Application Development
Topic
Safety Concept Assumptions
Page
Safety Concept Assumptions
49
Basics of Application Development and Testing
50
Commissioning Life Cycle
51
Downloading the Safety Application Program
57
Uploading the Safety Application Program
57
Online Editing
57
Storing and Loading a Project from Nonvolatile Memory
58
Force Data
58
Inhibit a Module
58
Editing Your Safety Application
59
The safety concept assumes the following:
• If you are responsible for creating, operating, and maintaining the
application, you are fully qualified, specially trained, and experienced in
safety systems.
• You apply the logic correctly, meaning that programming errors can be
detected. Programming errors can be detected by strict adherence to
specifications, programming and naming rules.
• You perform a critical analysis of the application and use all possible
measures to detect a failure.
• You confirm all application downloads via a manual check of the safety
task signature.
• You perform a complete functional test of the entire system before the
operational startup of a safety-related system.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
49
Chapter 6
Safety Application Development
Table 9 - Controller Modes
Safety(1)
(up to and including)
Controller
Mode
Safety Task Status
Comments
(A valid program has been downloaded to the controller.)
Program
Unlocked
No signature
Run
Unlocked
No signature
(Development purposes
only)
•
•
•
•
Forcing allowed
Online editing allowed
Safety memory is isolated, but is unprotected (read/write).
Safety Task logic is being scanned.
Primary and partner controllers process logic, cross-compare logic outputs. Logic outputs are
written to safety outputs.
Run
Locked
No signature
PLd/Cat. 3
Control reliable
SIL 2
•
•
•
•
•
New forces are not allowed. Existing forces are maintained.
Online editing is not allowed.
Safety memory is protected (read only)
Safety task logic is scanned.
Primary and partner controllers process logic, cross-compare logic outputs. Logic outputs are
written to safety outputs.
Run
Unlocked
With signature
Ple/Cat. 4
Control reliable
SIL 3
•
•
•
•
•
Run
Locked
With signature
Ple/Cat. 4
Control reliable
SIL 3
•
•
•
•
•
• I/O connections established
• Safety Task logic is not being scanned.
Forces are not allowed. (They must be removed to generate a safety task signature.)
Online editing is not allowed.
Safety memory is protected (read only).
Safety task logic is scanned.
Primary and partner controllers process logic, cross-compare logic outputs. Logic outputs are
written to safety outputs.
• Safety task signature is unprotected and can be deleted by anyone who has access to the controller.
Forces are not allowed. (They must be removed to generate a safety task signature.)
Online editing is not allowed.
Safety memory is protected (read only).
Safety task logic is scanned.
Primary and partner controllers process logic, cross-compare logic outputs. Logic outputs are
written to safety outputs.
• Safety task signature is protected. Users must enter the unlock password to unlock the controller
before they can delete the safety task signature.
(1) To achieved this level, you must adhere to the safety requirements defined in this publication.
Basics of Application
Development and Testing
50
The application program for the intended SIL 3 system should be developed by
the system integrator or a user trained and experienced in safety applications. The
developer must follow good design practices:
• Use functional specifications, including flow charts, timing diagrams, and
sequence charts.
• Perform a review of safety task logic.
• Perform application validation.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Safety Application Development
Commissioning Life Cycle
Chapter 6
The flowchart below shows the steps required for commissioning a GuardLogix
system. The items in bold text are explained in the following sections.
Figure 15 - Commission the System
Specify the Control Function
Create Project
Online
Create Project
Offline
Attach to Controller and Download
Test the Application Program
Make required
modifications
Generate Safety Task Signature
Project Verification Test
Tests
Passed?
No
Delete Safety Task Signature
Yes
Confirm the Project
Record Safety Task Signature
Fill out the Safety Checklists in Appendix D
Safety Validation (Independent Review)
Project
Valid?
No
Yes
Lock the Controller / End
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
51
Chapter 6
Safety Application Development
Specification of the Control Function
You must create a specification for your control function. Use this specification to
verify that program logic correctly and fully addresses your application’s
functional and safety control requirements. The specification may be presented
in a variety of formats, depending on your application. However, the specification
must be a detailed description that includes the following (if applicable):
• Sequence of operations
• Flow and timing diagrams
• Sequence charts
• Program description
• Program print out
• Written descriptions of the steps with step conditions and actuators to be
controlled, including the following:
– Input definitions
– Output definitions
– I/O wiring diagrams and references
– Theory of operation
• Matrix or table of stepped conditions and the actuators to be controlled,
including the sequence and timing diagrams
• Definition of marginal conditions, for example, operating modes and
EMERGENCY STOP
The I/O portion of the specification must contain the analysis of field circuits,
that is, the type of sensors and actuators.
• Sensors (Digital or Analog)
– Signal in standard operation (dormant current principle for digital
sensors, sensors OFF means no signal)
– Determination of redundancies required for SIL levels
– Discrepancy monitoring and visualization, including your diagnostic
logic
• Actuators
– Position and activation in standard operation (normally OFF)
– Safe reaction/positioning when switching OFF or power failure
– Discrepancy monitoring and visualization, including your diagnostic
logic
52
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Safety Application Development
Chapter 6
Create the Project
The logic and instructions used in programming the application must be the
following:
• Easy to understand
• Easy to trace
• Easy to change
• Easy to test
All logic should be reviewed and tested. Keep safety-related logic and standard
logic separate.
Label the Program
The application program is clearly identified by one of the following:
• Name
• Date
• Revision
• Any other user identification
Test the Application Program
This step consists of any combination of Run and Program modes, online or
offline edits, upload and download, and informal testing that is required to get an
application running properly in preparation for the Project Verification test.
Generate the Safety Task Signature
The safety task signature uniquely identifies each project, including its logic, data,
and configuration. The safety task signature is composed of an ID (identification
number), date, and time.
You can generate the safety task signature if all of the following conditions are
true:
• RSLogix 5000 software is online with the controller.
• The controller is in Program mode.
• The controller is safety-unlocked.
• The controller has no safety forces or pending online safety edits.
• The safety task status is OK.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
53
Chapter 6
Safety Application Development
Once application program testing is complete, you must generate the safety task
signature. The programming software automatically uploads the safety task
signature after it is generated.
IMPORTANT
To verify the integrity of every download, you must manually record the
safety task signature after initial creation and check the safety task
signature after every download to make sure that it matches the original.
You can delete the safety task signature only when the GuardLogix controller is
safety-unlocked and, if online, the keyswitch is in the REM or PROG position.
When a safety task signature exists, the following actions are not permitted
within the safety task:
• Online or offline programming or editing of safety components
• Forcing Safety I/O
• Data manipulation (except through routine logic or another GuardLogix
controller)
Project Verification Test
To check the application program for adherence to the specification, you must
generate a suitable set of test cases covering the application. The set of test cases
must be filed and retained as the test specification.
You must include a set of tests to prove the validity of the calculations (formulas)
used in your application logic. Equivalent range tests are acceptable. These are
tests within the defined value ranges, at the limits, or in invalid value ranges. The
necessary number of test cases depends on the formulas used and must comprise
critical value pairs.
Active simulation with sources (field devices) must also be included, as it is the
only way to verify that the sensors and actuators in the system are wired correctly.
Verify the operation of programmed functions by manually manipulating sensors
and actuators.
You must also include tests to verify the reaction to wiring faults and network
communication faults.
Project verification includes required functional verification tests of fault
routines, and input and output channels, to be sure that the safety system operates
properly.
To perform a functional verification test on the GuardLogix controller, you must
perform a full test of the application. You must toggle each sensor and actuator
involved in every safety function. From a controller perspective, this means
toggling the I/O point going into the controller, not necessarily the actual
activators. Be sure to test all shutdown functions, because these functions are not
typically exercised during normal operation. Also, be aware that a functional
verification test is valid only for the specific application tested. If the controller is
54
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Safety Application Development
Chapter 6
moved to another application, you must also perform start-up and functional
verification testing on the controller in the context of its new application.
See Functional Verification Tests on page 12 for more information.
Confirm the Project
You must print or view the project, and compare the uploaded safety I/O and
controller configurations, safety data, and safety task program logic to make sure
that the correct safety components were downloaded, tested, and retained in the
safety application program.
If your application program contains a safety Add-On Instruction that has been
sealed with an instruction signature, you must also compare the instruction
signature, date/time, and safety instruction signature to the values you recorded
when you sealed the Add-On Instruction.
See Appendix B, Safety Add-On Instructions for information on creating and
using safety Add-On Instructions in SIL 3 applications.
The steps below illustrate one method for confirming the project.
1. With the controller in Program mode, save the project.
2. Answer Yes to the Upload Tag Values prompt.
3. With RSLogix 5000 software offline, save the project with a new name,
such as Offlineprojectname.ACD, where projectname is the name of your
project.
This is the new tested master project file.
4. Close the project.
5. Move the original project archive file out of its current directory.
You can delete this file or store it in an archival location. This step is
required because if RSLogix 5000 software finds the projectname.ACD in
this directory, it will correlate it with the controller project and will not
perform an actual upload.
6. With the controller still in Program mode, upload the project from the
controller.
7. Save the uploaded project as Onlineprojectname.ACD, where
projectname is the name of your project.
8. Answer Yes to the Upload Tag Values prompt.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
55
Chapter 6
Safety Application Development
9. Use the RSLogix 5000 Program Compare utility to perform these
comparisons:
• Compare all of the properties of the GuardLogix controller and CIP
Safety I/O modules.
• Compare all of the properties of the safety task, safety programs and
safety routines.
• Compare all of the logic in the safety routines.
Safety Validation
An independent, third-party review of the safety system may be required before
the system is approved for operation. An independent, third-party certification is
required for IEC 61508 SIL 3.
Lock the GuardLogix Controller
The GuardLogix controller system can be safety-locked to help protect safety
control components from modification. However, safety-locking the controller is
not a requirement for SIL 3 applications. The safety-lock feature applies only to
safety components, such as the safety task, safety programs, safety routines, safety
tags, safety Add-On Instructions, safety I/O, and safety task signature. However,
safety-locking alone does not satisfy SIL 3 requirements.
No aspect of safety can be modified while the controller is in the safety-locked
state. When the controller is safety-locked, the following actions are not
permitted in the safety task:
• Online or offline programming or editing
• Forcing safety I/O
• Data manipulation (except through routine logic or another GuardLogix
controller)
• Creating or editing safety Add-On Instructions
• Generating or deleting the safety task signature
The default state of the controller is safety-unlocked. You may place the safety
application in a safety-locked state regardless of whether you are online or offline,
and regardless of whether you have the original source of the program. However,
no safety forces or pending safety edits may be present. Safety-locked or
-unlocked status cannot be modified when the keyswitch is in the RUN position.
To provide an additional layer of protection, separate passwords may be used for
safety-locking or -unlocking the controller. Passwords are optional.
56
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Safety Application Development
Downloading the Safety
Application Program
Chapter 6
Upon download, application testing is required unless a safety task signature
exists.
IMPORTANT
To verify the integrity of every download, you must manually record the
safety task signature after initial creation and check the safety task
signature after every download to make sure that it matches the original.
Downloads to a safety-locked GuardLogix controller are allowed only if the
safety task signature, the hardware series, and the operating system version of the
offline project all match those contained in the target GuardLogix controller and
the controller’s safety task status is OK.
IMPORTANT
If the safety task signature does not match and the controller is
safety-locked, you must unlock the controller to download. In this case,
downloading to the controller deletes the safety task signature. As a result,
you must revalidate the application.
ATTENTION: The USB port is intended for temporary local programming
purposes only and not intended for permanent connection.
Uploading the Safety
Application Program
If the GuardLogix controller contains a safety task signature, the safety task
signature will be uploaded with the project. This means that any changes to
offline safety data will be overwritten as a result of the upload.
Online Editing
If there is no safety task signature and the controller is safety-unlocked, you can
perform online edits to your safety routines.
TIP
You cannot edit standard or safety Add-On Instructions while online.
Pending edits cannot exist when the controller is safety-locked or when there is a
safety task signature. Online edits may exist when the controller is safety-locked.
However, they may not be assembled or cancelled.
TIP
Online edits in standard routines are unaffected by the safety-locked or
-unlocked state.
See page 59 for more information on making edits to your application program.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
57
Chapter 6
Safety Application Development
Storing and Loading a
Project from Nonvolatile
Memory
In revision 18 or later, GuardLogix controllers support firmware upgrades and
user program storage and retrieval by using a memory card. In a 1756
GuardLogix system, only the primary controller uses a memory card for
nonvolatile memory.
When you store a safety application project on a memory card, Rockwell
Automation recommends you select Remote Program as the Load mode, that is,
the mode the controller should enter following the load. Prior to actual machine
operation, operator intervention is required to start the machine.
You can initiate a load from nonvolatile memory only under these conditions:
• If the controller type specified by the project stored in nonvolatile memory
matches your controller type
• If the major and minor revisions of the project in nonvolatile memory
matches the major and minor revisions of your controller
• If your controller is not in Run mode
Loading a project to a safety-locked controller is allowed only when the safety
task signature of the project stored in nonvolatile memory matches the project on
the controller. If the signatures do not match or the controller is safety-locked
without a safety task signature, you must first unlock the controller before
attempting to update the controller via nonvolatile memory.
IMPORTANT
Force Data
All data contained in an I/O, produced, or consumed safety tag, including
CONNECTION_STATUS, can be forced while the project is safety-unlocked
and no safety task signature exists. However, forces must be uninstalled, not just
disabled, on all safety tags before the safety project can be safety-locked or a safety
task signature can be generated. You cannot force safety tags while the project is
safety-locked or when a safety task signature exists.
TIP
Inhibit a Module
If you unlock the controller and initiate a load from nonvolatile memory,
the safety-lock status, passwords, and safety task signature will be set to
the values contained in nonvolatile memory once the load is complete.
You can install and uninstall forces on standard tags regardless of the
safety-locked or -unlocked state.
You cannot inhibit or uninhibit safety I/O modules or producer controllers if the
application is safety-locked or a safety task signature exists.
Follow these steps to inhibit a specific safety I/O module.
1. In RSLogix 5000 software, right-click the module and choose Properties.
2. On the Module Properties dialog box, click the Connection tab.
58
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Safety Application Development
Chapter 6
3. Check Inhibit Connection and click Apply.
The module is inhibited whenever the checkbox is checked. If a
communication module is inhibited, all downstream modules are also
inhibited.
Editing Your Safety
Application
The following rules apply to changing your safety application in RSLogix 5000
software:
• Only authorized, specially-trained personnel can make program edits.
These personnel should use all supervisory methods available, for example,
using the controller keyswitch and software password protections.
• When authorized, specially-trained personnel make program edits, they
assume the central safety responsibility while the changes are in progress.
These personnel must also maintain safe application operation.
• When editing online, you must use an alternate protection mechanism to
maintain the safety of the system.
• You must sufficiently document all program edits, including:
– authorization.
– impact analysis.
– execution.
– test information.
– revision information.
• If online edits exist only in the standard routines, those edits are not
required to be validated before returning to normal operation.
• You must make sure that changes to the standard routine, with respect to
timing and tag mapping, are acceptable to your safety application.
• You can edit the logic portion of your program while offline or online, as
described in the following sections.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
59
Chapter 6
Safety Application Development
Performing Offline Edits
When offline edits are made to only standard program elements, and the safety
task signature matches following a download, you can resume operation.
When offline edits affect the safety program, you must revalidate all affected
elements of the application, as determined by the impact analysis, before
resuming operation.
The flowchart on page 61 illustrates the process for offline editing.
Performing Online Edits
If online edits affect the safety program, you must revalidate all affected elements
of the application, as determined by the impact analysis, before resuming
operation. The flowchart on page 61 illustrates the process for online editing.
TIP
Limit online edits to minor program modifications such as setpoint changes
or minor logic additions, deletions, and modifications.
Online edits are affected by the safety-lock and safety task signature features of
the GuardLogix controller.
See Generate the Safety Task Signature on page 53 and Lock the GuardLogix
Controller on page 56 for more information.
For detailed information on how to edit ladder logic in RSLogix 5000 software
while online, see the Logix5000 Controllers Quick Start, publication
1756-QS001.
Modification Impact Test
Any modification, enhancement, or adaptation of validated software must be
planned and analyzed for any impact to the functional safety system. All
appropriate phases of the software safety lifecycle need to be carried out as
indicated by the impact analysis. At a minimum, functional testing of all
impacted software must be carried out. All modifications to software
specifications must be documented. Test results must also be documented. Refer
to IEC 61508-3, Section 7.8 Software Modification, for detailed information.
60
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Safety Application Development
Chapter 6
Figure 16 - Online and Offline Edit Process
Offline Edit
Online Edit
Open Project
Attach to Controller
Any Safety
Changes?
Yes
No
Any Safety
Changes?
No
Make Desired
Modifications to Standard
Logic
Yes
Unlock the Controller
Unlock the Controller
Make Desired
Modifications to Standard
Logic
Delete Safety
Application Signature
Attach to Controller and
Download
Make Desired
Modifications to Safety Logic
Test the Application Program
Delete Safety
Application Signature
Make Desired
Modifications
Test the Application Program
Attach to Controller and
Download
Confirm the Project
END
Test the Application Program
Generate Safety Task Signature
Make Required
Modifications
Modification Impact Test
Tests
Passed?
No
Delete Safety
Application Signature
Yes
Confirm the Project
END
Record Safety
Application Signature
Safety Validation
(Independent Review)
Project
Valid?
No
Yes
Lock the Controller
END
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
61
Chapter 6
Safety Application Development
Notes:
62
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Chapter
7
Monitor Status and Handle Faults
Topic
Page
Monitoring System Status
63
GuardLogix System Faults
66
The GuardLogix architecture provides you with many ways of detecting and
reacting to faults in the system. The first way that you can handle faults is to make
sure you have completed the checklists for your application (see Appendix D).
Monitoring System Status
You can view the status of safety tag connections. You can also determine current
operating status by interrogating various device objects. It is your responsibility to
determine what data is most appropriate to initiate a shutdown sequence.
CONNECTION_STATUS Data
The first member of the tag structure associated with safety input data and
produced/consumed safety tag data contains the status of the connection. This
member is a pre-defined data type called CONNECTION_STATUS.
Figure 17 - Data Type Dialog Box
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
63
Chapter 7
Monitor Status and Handle Faults
The first two bits of the CONNECTION_STATUS data type contain a device’s
RunMode and ConnectionFaulted status bits. The following table describes the
combinations of the RunMode and ConnectionFaulted states.
Table 10 - Safety Connection Status
RunMode
Status
ConnectionFaulted
Status
Safety Connection Operation
1 = Run
0 = Valid
Data is actively being controlled by the producing device. The
producing device is in Run mode.
0 = Idle
0 = Valid
The connection is active and the producing device is in the Idle state.
The safety data is reset to zero.
0 = Idle
1 = Faulted
The safety connection is faulted. The state of the producing device is
unknown. The safety data is reset to zero.
1
1
Invalid state.
ATTENTION: Safety I/O connections and produced/consumed connections
cannot be automatically configured to fault the controller if a connection is lost
and the system transitions to the safe state. Therefore, if you need to detect a
module fault to be sure that the system maintains SIL 3, you must monitor the
Safety I/O CONNECTION_STATUS bits and initiate the fault via program logic.
Input and Output Diagnostics
Guard I/O modules provide pulse test and monitoring capabilities. If the module
detects a failure, it sets the offending input or output to its safety state and reports
the failure to the controller. The failure indication is made via input or output
status and is maintained for a configurable amount of time after the failure is
repaired.
IMPORTANT
You are responsible for providing application logic to latch these I/O failures
and to make sure the system restarts properly.
I/O Module Connection Status
The CIP safety protocol provides status for each I/O module in the safety
system. If an input connection failure is detected, the operating system sets all
device inputs to their de-energized (safety) state, and the associated input status
to faulted. If an output connection failure is detected, the operating system sets
the associated output status to faulted. The output module de-energizes the
outputs.
IMPORTANT
64
You are responsible for providing application logic to latch these I/O failures
and to make sure the system restarts properly.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Monitor Status and Handle Faults
Chapter 7
De-energize to Trip System
GuardLogix controllers are part of a de-energize to trip system, which means that
zero is the safe state. Some, but not all, safety module faults cause all module
inputs or outputs to be set to zero (safe state). Faults associated to a specific input
channel result in that specific channel being set to zero; for example, a pulse test
fault that is specific to channel 0 results in channel 0 input data being set to the
safe state (0). If a fault is general to the module and not to a specific channel, the
combined status bit displays the fault status and all module data is set to the safe
state (0).
For information on how to use the RSLogix 5000 software, version 14 safety
application instructions, see Appendix F of this manual and the GuardLogix
Safety Application Instructions Safety Reference Manual, publication 1756RM095.
Get System Value (GSV) and Set System Value (SSV) Instructions
The GSV and SSV instructions let you get (GSV) and set (SSV) controller
system data stored in device objects. When you enter a GSV/SSV instruction, the
programming software displays the valid object classes, object names, and
attribute names for each instruction. Restrictions exist for using the GSV and
SSV instructions with safety components.
IMPORTANT
The safety task cannot perform GSV or SSV operations on standard
attributes.
The attributes of safety objects that can be written by the standard task are
for diagnostic purposes only. They do not affect safety task execution.
For more information on which safety attributes are accessible via GSV and SSV
instructions, refer to the following:
• GuardLogix Controllers User Manual, publication 1756-UM020
• 1768 Compact GuardLogix Controllers User Manual,
publication 1768-UM002
For general information on using GSV and SSV instructions, refer to the
Logix5000 Controllers General Instructions Reference Manual, publication
1756-RM003.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
65
Chapter 7
Monitor Status and Handle Faults
GuardLogix System Faults
Faults in the GuardLogix system fall into these three categories:
• Nonrecoverable controller faults
• Nonrecoverable safety faults
• Recoverable faults
For information on handling faults, refer to the GuardLogix Controllers User
Manual, publication 1756-UM020, or the 1768 Compact GuardLogix
Controllers User Manual, publication 1768-UM002.
Nonrecoverable Controller Faults
A nonrecoverable controller fault occurs if the controller’s internal diagnostics
fail. Partnership is lost when a nonrecoverable controller fault occurs in either the
primary controller or the safety partner, causing the other to generate a
nonrecoverable watchdog timeout fault. Standard task and safety task execution
stops, and Safety I/O transitions to the safe state.
Recovery from a nonrecoverable controller fault requires a download of the
application program.
Nonrecoverable Safety Faults
In the event of a non-recoverable safety fault, the controller logs the fault to the
controller-scoped fault handler and shuts down the safety task, including Safety
I/O and safety logic.
To recover from a nonrecoverable safety fault, safety memory is reinitialized
either from the safety task signature (happens automatically when you clear the
fault) or, if no safety task signature exists, via an explicit download of the safety
project.
You can override the safety fault by clearing the fault log entry through the
controller-scoped safety fault handler. This allows standard tasks to keep
running.
ATTENTION: Overriding the safety fault does not clear it. If you override the
safety fault, it is your responsibility to prove that doing so maintains SIL 3.
66
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Monitor Status and Handle Faults
Chapter 7
Recoverable Faults
Controller faults caused by user programming errors in a safety program trigger
the controller to process the logic contained in the project’s safety program fault
handler. The safety program fault handler provides the application with the
opportunity to resolve the fault condition and then recover.
ATTENTION: You must provide proof to your certifying agency that automatic
recovery from recoverable faults maintains SIL 3.
When a safety program fault handler does not exist or the fault is not recovered
by it, the controller processes the logic in the controller-scoped fault handler,
terminating safety program logic execution and leaving safety I/O connections
active, but idle.
IMPORTANT
When the execution of safety program logic is terminated due to a
recoverable fault that is not handled by the safety program fault handler,
the safety I/O connections are closed and reopened to reinitialize safety
connections.
If user logic is terminated as a result of a recoverable fault that is not recovered,
safety outputs are placed in the safe state and the producer of safety-consumed
tags commands the consumers to place them in a safe state.
TIP
When using safety I/O for standard applications, safety I/O will be
commanded to the safe state if user logic is terminated as a result of a
recoverable fault that is not recovered.
If a recoverable safety fault is overridden in the controller-scoped fault handler,
only standard tasks keep running. If the fault is not overridden, the standard tasks
are also shut down.
ATTENTION: Overriding the safety fault does not clear it. If you override the
safety fault, it is your responsibility to prove that doing so maintains SIL 3.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
67
Chapter 7
Monitor Status and Handle Faults
Notes:
68
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Appendix
A
Safety Instructions
Topic
Page
Safety Application Instructions
69
Metal Form Safety Application Instructions
70
Safety Instructions
71
Additional Resources
72
For the latest information, see our safety certificates at
http://www.rockwellautomation.com/products/certification/safety/.
Safety Application
Instructions
Table 11 - RSLogix 5000 Software, Version 20 and Later, Safety Application Instructions
Mnemonic
Name
DCA
Dual Channel Input - Analog
(integer version)
DCAF
Dual Channel Input - Analog
(floating point version)
Purpose
Certification
Monitors two analog values for deviation and range tolerance.
TÜV
Table 12 - RSLogix 5000 Software, Version 17 and Later, Safety Application Instructions
Mnemonic
Name
Purpose
Certification
CROUT
Configurable Redundant Output
Controls and monitors redundant outputs.
• BG
• TÜV
DCS
Dual Channel Input - Stop
Monitors dual-input safety devices whose main purpose is to provide a stop function, such as an E- • BG
stop, light curtain, or gate switch.
• TÜV
DCST
Dual Channel Input - Stop With Test Monitors dual-input safety devices whose main purpose is to provide a stop function, such as an E- • BG
stop, light curtain, or gate switch. It includes the added capability of initiating a functional test of • TÜV
the stop device.
DCSTL
Dual Channel Input - Stop With Test
and Lock
Monitors dual-input safety devices whose main purpose is to provide a stop function, such as an E- • BG
stop, light curtain, or gate switch. It includes the added capability of initiating a functional test of • TÜV
the stop device and can monitor a feedback signal from a safety device and issue a lock request to a
safety device.
DCSTM
Dual Channel Input - Stop With Test
and Mute
Monitors dual-input safety devices whose main purpose is to provide a stop function, such as an E- TÜV
stop, light curtain, or gate switch. It includes the added capability of initiating a functional test of
the stop device and the ability to mute the safety device.
DCM
Dual Channel Input - Monitor
Monitors dual-input safety devices.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
• BG
• TÜV
69
Appendix A
Safety Instructions
Table 12 - RSLogix 5000 Software, Version 17 and Later, Safety Application Instructions
Mnemonic
Name
Purpose
Certification
DCSRT
Dual Channel Input - Start
Energizes dual-input safety devices whose main function is to start a machine safely, for example
an enable pendant.
• BG
• TÜV
SMAT
Safety Mat
Indicates whether or not the safety mat is occupied.
TÜV
THRSe
Two-Hand Run Station – Enhanced
Monitors two diverse safety inputs, one from a right-hand push button and one from a left-hand
push button, to control a single output. Features configurable channel-to-channel discrepancy
time and enhanced capability for bypassing a two-hand run station.
• BG
• TÜV
TSAM
Two Sensor Asymmetrical Muting
Provides temporary, automatic disabling of the protective function of a light curtain, using two
muting sensors arranged asymmetrically.
TÜV
TSSM
Two Sensor Symmetrical Muting
Provides temporary, automatic disabling of the protective function of a light curtain, using two
muting sensors arranged symmetrically.
TÜV
FSBM
Four Sensor Bidirectional Muting
Provides temporary, automatic disabling of the protective function of a light curtain, using four
sensors arranged sequentially before and after the light curtain’s sensing field.
TÜV
Metal Form Safety
Application Instructions
These instructions are available in RSLogix 5000 software, version 17 and later.
Mnemonic
Name
Purpose
Certification
CBCM
Clutch Brake Continuous Mode
Used for press applications where continuous operation is desired.
• BG
• TÜV
CBIM
Clutch Brake Inch Mode
Used for press applications where minor slide adjustments are required, such as press setup.
• BG
• TÜV
CBSSM
Clutch Brake Single Stoke Mode
Used in single-cycle press applications.
• BG
• TÜV
CPM
Crankshaft Position Monitor
Used to determine the slide position of the press.
• BG
• TÜV
CSM
Camshaft Monitor
Monitors motion for the starting, stopping, and running operations of a camshaft.
• BG
• TÜV
EPMS
Eight-position Mode Selector
Monitors eight safety inputs to control one of the eight outputs corresponding to the active input.
• BG
• TÜV
AVC
Auxiliary Valve Control
Controls an auxiliary valve that is used in conjunction with a main valve.
TÜV
MVC
Main Valve Control
Controls and monitors a main valve.
• BG
• TÜV
MMVC
Maintenance Manual Valve
Control
Used to manually drive a valve during maintenance operations.
• BG
• TÜV
70
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Safety Instructions
Appendix A
Routines in the safety task may use these ladder logic safety instructions.
Safety Instructions
Table 13 - Ladder Logic Safety Instructions
Type
Array (File)
Bit
Timer
Compare
Move
Logical
Mnemonic
Name
Purpose
RSLogix 5000
Version(6)
FAL(1)
File Arithmetic and Logic
Perform copy, arithmetic, logic, and function operations on data stored in an array
20
FLL(1)
File Fill
Fill the element of an array with the Source Value, while leaving the source value unchanged
20
FSC(1)
File Search and Compare
Compare the value in an array, element by element
20
SIZE(1)
Size In Elements
Find the size of a dimension of an array
20
XIC
Examine If Closed
Enable outputs when a bit is set
14
14
XIO
Examine If Open
Enable outputs when a bit is cleared
OTE
Output Energize
Set a bit
14
OTL
Output Latch
Set a bit (retentive)
14
OTU
Output Unlatch
Clear bit (retentive)
14
ONS
One Shot
Triggers an event to occur one time
14
OSR
One Shot Rising
Triggers an event to occur one time on the false-to-true (rising) edge of change-of-state
14
OSF
One Shot Falling
Triggers an event to occur one time on the true-to-false (falling) edge of change-of-state
14
TON
Timer On Delay
Time how long a timer is enabled
14
TOF
Timer Off Delay
Time how long a timer is disabled
14
RTO
Retentive Timer On
Accumulate time
14
CTU
Count Up
Count up
14
CTD
Count Down
Count down
14
RES
Reset
Reset a timer or counter
14
CMP(1)(2)
Compare
Perform a comparison on the arithmetic operations you specify in the expression
20
EQU
Equal To
Test whether two values are equal
14
GEQ
Greater Than Or Equal To
Test whether one value is greater than or equal to a second value
14
GRT
Greater Than
Test whether one value is greater than a second value
14
LEQ
Less Than Or Equal To
Test whether one value is less than or equal to a second value
14
LES
Less Than
Test whether one value is less than a second value
14
MEQ
Masked Comparison for
Equal
Pass source and compare values through a mask and test whether they are equal
14
NEQ
Not Equal To
Test whether one value is not equal to a second value
14
LIM
Limit Test
Test whether a value falls within a specified range
14
CLR
Clear
Clear a value
14
COP(3)
Copy
Copy a value
14
MOV
Move
Copy a value
14
MVM
Masked Move
Copy a specific part of an integer
14
SWPB(1)
Swap Byte
Rearrange the bytes of a value
20
AND
Bitwise AND
Perform bitwise AND operation
14
NOT
Bitwise NOT
Perform bitwise NOT operation
14
OR
Bitwise OR
Perform bitwise OR operation
14
XOR
Bitwise Exclusive OR
Perform bitwise exclusive OR operation
14
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
71
Appendix A
Safety Instructions
Table 13 - Ladder Logic Safety Instructions
Type
Program
Control
Math/
Compute
I/O
(1)
(2)
(3)
(4)
(5)
(6)
Mnemonic
Name
Purpose
RSLogix 5000
Version(6)
JMP
Jump To Label
Jump over a section of logic that does not always need to be executed (skips to referenced
label instruction)
14
LBL
Label
Labels an instruction so that it can be referenced by a JMP instruction
14
JSR
Jump to Subroutine
Jump to a separate routine
14
RET
Return
Return the results of a subroutine
14
SBR
Subroutine
Pass data to a subroutine
14
TND
Temporary End
Mark a temporary end that halts routine execution
14
MCR
Master Control Reset
Disable all the rungs in a section of logic
14
AFI
Always False Instruction
Disable a rung
14
NOP
No Operation
Insert a placeholder in the logic
14
EVENT
Trigger Event Task
Trigger one execution of an event task(5)
20
ADD
Add
Add two values
14
CPT(1)
Compute
Perform the arithmetic operation defined in the expression
20
SUB
Subtract
Subtract two values
14
MUL
Multiply
Multiply two values
14
DIV
Divide
Divide two values
14
MOD
Modulo
Determine the remainder after one value is divided by a second value
14
SQR
Square Root
Calculate the square root of a value
14
NEG
Negate
Take the opposite sign of a value
14
ABS
Absolute Value
Take the absolute value of a value
14
GSV(4)
Get System Value
Get controller status information
14
SSV(4)
Set System Value
Set controller status information
14
Supported only on 1756-L7xS and 1756-L7xSXT controllers. For the data type REAL, a floating point format is supported for safety routines on 1756-L7xS and 1756-L7xSXT controllers.
Advanced operands like SIN, COS, and TAN are not supported in safety routines.
The length operand must be a constant when the COP instruction is used in a safety routine. The length of the source and the destination must be the same.
Refer to the GuardLogix Controllers User Manual, publication 1756-UM020, for special considerations when using the GSV and SSV instructions.
The event instruction will trigger a scan of the standard task.
Available in this version and later.
Additional Resources
72
Refer to these publications for more information.
Resource
Description
GuardLogix Safety Application Instruction Set Reference
Manual, publication 1756-RM095
Provides more information on the safety application
instructions
Logix5000 Controllers General Instructions Reference Manual,
publication 1756-RM003
Contains detailed information on the Logix
instruction set
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Appendix
B
Safety Add-On Instructions
Topic
Page
Creating and Using a Safety Add-On Instruction
73
Additional Resources
78
With RSLogix 5000 software, version 18 and later, you can create safety Add-On
Instructions. Safety Add-On Instructions let you encapsulate commonly-used
safety logic into a single instruction, making it modular and easier to reuse.
Safety Add-On Instructions use the instruction signature of high-integrity AddOn Instructions and also a SIL 3 safety instruction signature for use in safetyrelated functions up to and including SIL 3.
Creating and Using a Safety
Add-On Instruction
The flowchart on page 74 shows the steps required for creating a safety Add-On
Instruction and then using that instruction in a SIL 3 safety application program.
The shaded items are steps unique to Add-On Instructions. The items in bold
text are explained in the pages following the flowchart.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
73
Appendix B
Safety Add-On Instructions
Figure 18 - Flowchart for Creating and Using Safety Add-On Instructions
To Use a Safety Add-On Instruction
To Create a Safety Add-On Instruction
To Modify a Safety AddOn Instruction
(off-line)
Create or Open a Project
Create Add-On Instruction Test Project
Import Safety Add-On Instruction
Create Safety Add-On Instruction
Create/modify Application
Generate Instruction Signature
Download
Create/Modify Test Program
Verify Safety Add-On Instruction Signatures
Download
(Generate Safety Instruction
Signature)
Modify Safety Add-On
Instruction
Go back to original test
project
Delete Instruction Signature
Change Mode to Run
Go Off-line
Perform SIL 3 Add-On Instruction
Qualification Test
No
Instruction Signature Valid?
Yes
Go back to original test
project
No
Safety
Instruction Signature Valid?
Yes
Delete Safety Task Signature, if it
exists
No
All
Tests Pass?
Test the Application Program
Yes
Confirm Project
Change Mode to Program
Safety Validate the Add-On Instruction
Create Safety Task Signature
Create Signature History Entry
(offline)
Confirm Project
Make Required
Modifications
Record Instruction Signature, Date/Time, and
Safety Instruction Signature
Change Mode to Run
Delete Safety Task Signature
Export Safety Add-On Instruction
Project Verification Test
No
Are
Changes to the Add-On
Instruction Required?
Safety Add-On Instruction available
for use
No
All
Tests Pass?
Yes
Yes
Record Safety Task Signature
Safety Validate Project
No
Project Valid?
Yes
Done
74
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Safety Add-On Instructions
Appendix B
Create Add-On Instruction Test Project
You need to create a unique test project, specifically for creating and testing the
safety Add-On Instruction. This must be a separate and dedicated project to
minimize any unexpected influences.
Follow the guidelines for projects described in Create the Project on page 53.
Create a Safety Add-On Instruction
For guidance in creating Add-On Instructions, refer to the Logix5000
Controllers Add-On Instruction Programming Manual, publication
1756-PM010.
Generate Instruction Signature
The instruction signature lets you quickly determine if the instruction has been
modified. Each Add-On Instruction has the ability to have its own signature. The
instruction signature is required when an Add-On Instruction is used in safetyrelated functions, and may be required for regulated industries. Use it when your
application calls for a higher level of integrity.
The instruction signature consists of an ID number and timestamp that identifies
the contents of the Add-On Instruction at a given point in time.
Once generated, the instruction signature seals the Add-On Instruction,
preventing it from being edited while the signature is in place. This includes rung
comments, tag descriptions, and any instruction documentation that was created.
When the instruction is sealed, you can perform only these actions:
• Copy the instruction signature
• Create or copy a signature history entry
• Create instances of the Add-On Instruction
• Download the instruction
• Remove the instruction signature
• Print reports
When an instruction signature has been generated, RSLogix 5000 software
displays the instruction definition with the seal icon.
IMPORTANT
If you plan to protect your Add-On Instruction by using the source
protection feature in RSLogix 5000 software, you must enable source
protection prior to generating the instruction signature.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
75
Appendix B
Safety Add-On Instructions
Download and Generate Safety Instruction Signature
When a sealed safety Add-On Instruction is downloaded for the first time, a
SIL 3 safety instruction signature is automatically generated. The safety
instruction signature is an ID number that identifies the execution characteristics
of the safety Add-On Instruction.
SIL 3 Add-On Instruction Qualification Test
Safety Add-On Instruction SIL 3 tests must be performed in a separate,
dedicated application to make sure unintended influences are minimized. The
developer must follow a well-designed test plan and perform a unit test of the
safety Add-On Instruction that exercises all possible execution paths through the
logic, including the valid and invalid ranges of all input parameters.
Development of all safety Add-On Instructions must meet IEC 61508 ‘Requirements for software module testing’, which provides detailed
requirements for unit testing.
Confirm the Project
You must print or view the project, and manually compare the uploaded safety I/
O and controller configurations, safety data, safety Add-On Instruction
definitions, and safety task program logic to make sure that the correct safety
components were downloaded, tested, and retained in the safety application
program.
See Confirm the Project on page 55 for a description of one method for
confirming a project.
Safety Validate Add-On Instructions
An independent, third-party review of the safety Add-On Instruction may be
required before the instruction is approved for use. An independent, third-party
validation is required for IEC 61508 SIL 3.
76
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Safety Add-On Instructions
Appendix B
Create Signature History Entry
The signature history provides a record for future reference. A signature history
entry consists of the instruction signature, the name of the user, the timestamp
value, and a user-defined description. Up to six history entries may be stored. You
must be offline to create a signature history entry.
TIP
The Signature Listing report in RSLogix 5000 software prints the instruction
signature, the timestamp, and the safety instruction signature. Print the
report by right-clicking Add-On Instruction in the Controller Organizer and
choosing Print>Signature Listing.
Export and Import the Safety Add-On Instruction
When you export a safety Add-On Instruction, choose the option to include all
referenced Add-On Instructions and User-Defined Types in the same export file.
By including referenced Add-On Instructions, you make it easier to preserve the
signatures.
When importing Add-On Instructions, consider these guidelines:
• You cannot import a safety Add-On Instruction into a standard project.
• You cannot import a safety Add-On Instruction into a safety project that
has been safety-locked or one that has a safety task signature.
• You cannot import a safety Add-On Instruction while online.
• If you import an Add-On Instruction with an instruction signature into a
project where referenced Add-On Instructions or User-Defined Types are
not available, you may need to remove the signature.
Verify Safety Add-On Instruction Signatures
After you download the application project containing the imported safety AddOn Instruction, you must compare the instruction signature value, the date and
timestamp, and the safety instruction signature values with the original values you
recorded prior to exporting the safety Add-On Instruction. If they match, the
safety Add-On Instruction is valid and you can continue with the validation of
your application.
Test the Application Program
This step consists of any combination of Run and Program mode, online or
offline program edits, upload and download, and informal testing that is required
to get an application running properly.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
77
Appendix B
Safety Add-On Instructions
Project Verification Test
Perform an engineering test of the application, including the safety system.
See Functional Verification Tests on page 12 and Project Verification Test on
page 54 for more information on requirements.
Safety Validate Project
An independent, third-party review of the safety system may be required before
the system is approved for operation. An independent, third-party validation is
required for IEC 61508 SIL 3.
Additional Resources
78
For more information on using Add-On Instructions, refer to these publications.
Resource
Description
Logix5000 Controllers Add-On Instructions Programming
Manual, publication 1756-PM010
Provides information on planning, creating, using,
importing and exporting Add-On Instructions in
RSLogix 5000 applications
Import/Export Project Components Programming
Manual, publication 1756-PM019
Contains detailed information on importing and
exporting
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Appendix
C
Reaction Times
Topic
System Reaction Time
Page
System Reaction Time
79
Logix System Reaction Time
79
To determine the system reaction time of any control chain, you must add up the
reaction times of all of components of the safety chain.
System Reaction Time = Sensor Reaction Time + Logix System Reaction Time
+ Actuator Reaction Time
Figure 19 - System Reaction Time
System Reaction Time
Sensor Reaction
Time
Input Reaction
Time
Safety Task
Reaction Time
Output Reaction
Time
Actuator
Reaction Time
Logix System Reaction Time
Input Module
Delay
Logix System Reaction Time
Input Connection
Reaction Time Limit
Safety Task Period
+
Safety Task Watchdog
Output Connection
Reaction Time Limit
Output Module
Delay
The following sections provide information on calculating the Logix System
Reaction Time for a simple input-logic-output chain and for a more complex
application using produced/consumed safety tags in the logic chain.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
79
Appendix C
Reaction Times
Simple Input-logic-output Chain
Figure 20 - Logix System Worst-case Reaction Time for Simple Input to Logic to Output
1. Safety Input
Module Delay
Communication Module
GuardLogix Controller
3. Safety Task Period +
Safety Task Watchdog
2. Safety Input Connection
Reaction Time Limit
4. Safety Output Connection
Reaction Time Limit
5. Safety Output
Module Delay
CIP Safety Network
The Logix System Reaction Time for any simple input to logic to output chain
consists of these five components:
1. Safety input module reaction time plus input delay time
2. Safety Input Connection Reaction Time Limit
(Read from the Module Properties dialog box in RSLogix 5000 software,
this value is a multiple of the safety input module connection RPI.)
3. Safety Task Period plus Safety Task Watchdog time
4. Safety Output Connection Reaction Time Limit
(Read from the Module Properties dialog box in RSLogix 5000 software,
this value is a multiple of the safety task period.)
5. Safety output module reaction time
To aid you in determining the reaction time of your particular control loop, a
Microsoft Excel spreadsheet is available in the Tools folder of the RSLogix 5000
software CD.
80
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Reaction Times
Appendix C
Logic Chain Using Produced/Consumed Safety Tags
Figure 21 - Logix System Reaction Time for Input to Controller A Logic to Controller B Logic to
Output Chain
4. P/C Safety Connection Reaction Time Limit
Ethernet
Network
Ethernet
Switch
Ethernet
Network
3. Safety Task Period +
Safety Task Watchdog
1. Safety Input
Module Delay
2. Safety Input Connection
Reaction Time Limit
Ethernet Module
DeviceNet Module
GuardLogix
Controller B
Ethernet Module
DeviceNet Module
GuardLogix
Controller A
5. Safety Task Period +
Safety Task Watchdog
6. Safety Output Connection
Reaction Time Limit
CIP Safety Network
7. Safety Output
Module Delay
CIP Safety Network
The Logix System Reaction Time for any input to controller A logic to controller
B logic to output chain consists of these seven components:
1. Safety input module reaction time plus input delay time
2. Safety Input Connection Reaction Time Limit
3. Safety Task Period plus Safety Task Watchdog time for Controller A
4. Produced/Consumed Safety Connection Reaction Time Limit
5. Safety Task Period plus Safety Task Watchdog time for Controller B
6. Safety Output Connection Reaction Time Limit
7. Safety output module reaction time
To aid you in determining the reaction time of your particular control loop, a
Microsoft Excel spreadsheet is available in the Tools folder of the RSLogix 5000
software CD.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
81
Appendix C
Reaction Times
Factors Affecting Logix
Reaction-time Components
The Logix Reaction Time components described in the previous sections can be
influenced by a number of factors.
Table 14 - Factors Affecting Logix System Reaction-time
These reaction time components
Are influenced by the following factors
Input module delay
Input module reaction time
Each input channels On-Off and Off-On delay settings
Safety Input Connection Reaction Time Limit
Input module settings for:
• Requested Packet Interval (RPI)
• Timeout Multiplier
• Delay Multiplier
The amount of network communication traffic
The system’s EMC environment
Safety Task Period and Safety Task Watchdog
Safety Task Period setting
Safety Task Watchdog setting
The number and execution time of instructions in the safety task
Any higher priority tasks that may preempt safety task execution
Produced/Consumed Safety Connection Reaction
Time Limit
Consumed tag settings for:
• RPI
• Timeout Multiplier
• Delay Multiplier
The amount of network communication traffic
The system’s EMC environment
Output Connection Reaction Time Limit
Safety Task Period setting
Output module’s settings for:
• Timeout Multiplier
• Delay Multiplier
The amount of network communication traffic
The system’s EMC environment
Output module delay
Output module reaction time
The following sections describe how to access data or settings for many of these
factors.
Accessing Input Module Delay Time Settings
To configure input module delay time in RSLogix 5000 software, follow these
steps.
1. In the configuration tree, right-click your I/O module and choose
Properties
2. Click the Input Configuration tab.
82
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Reaction Times
Appendix C
3. Adjust the input delay time as required for your application.
Accessing Input and Output Safety Connection Reaction Time Limit
The Connection Reaction Time Limit is defined by these three values:
Value
Description
Requested Packet Interval (RPI)
This is how often the input and output packets are placed on the wire (network).
Timeout Multiplier
The Timeout Multiplier is essentially the number of retries before timing out.
Network Delay Multiplier
The Network Delay Multiplier accounts for any known delays on the wire. When
these delays occur, timeouts can be avoided using this parameter.
By adjusting these values, you can adjust the Connection Reaction Time Limit.
To view or configure these settings, follow these steps.
1. In the configuration tree, right-click your I/O module and choose
Properties.
2. Click the Safety tab.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
83
Appendix C
Reaction Times
3. Click Advanced to open the Advanced Connection Reaction Time Limit
dialog box.
Configuring the Safety Task Period and Watchdog
The safety task is a periodic timed task. You select the task priority and watchdog
time via the Task Properties - Safety Task dialog box in your RSLogix 5000
project.
To access the safety task period and watchdog time settings, right-click the Safety
Task and choosing Properties.
The priority of the safety task is not a safety concern, as the safety task watchdog
monitors if the task is interrupted by higher priority task.
84
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Reaction Times
Appendix C
Accessing Produced/Consumed Tag Data
To view or configure safety tag connection data, follow these steps.
1. In the configuration tree, right-click Controller Tags and choose Edit tags.
2. In the Tag Editor, right-click the name of the tag and choose Edit
Properties.
3. Click Connection.
4. Click the Safety tab.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
85
Appendix C
Reaction Times
5. Click Advanced to view or edit the current settings.
Additional Resources
Refer to these publications for more information. Also, consult the product
documentation for your specific module for reaction times associated with CIP
Safety I/O modules.
Resource
Description
GuardLogix Controllers User Manual, publication 1756UM020
Contains information on configuring delay times and
reaction time limits for the input connection, safety task,
and output connection
1768 Compact GuardLogix Controllers User Manual,
publication 1768-UM002
86
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Appendix
D
Checklists for GuardLogix Safety Applications
Topic
Page
Checklist for GuardLogix Controller System
88
Checklist for Safety Inputs
89
Checklist for Safety Outputs
90
Checklist for Developing a Safety Application Program
91
The checklists in this appendix are required for planning, programming, and
startup of a SIL 3-certified GuardLogix application. They may be used as
planning guides as well as during functional verification testing. If used as
planning guides, the checklists can be saved as a record of the plan.
The checklists on the following pages provide a sample of safety considerations
and are not intended to be a complete list of items to verify. Your particular safety
application may have additional safety requirements, for which we have provided
space in the checklists.
TIP
Make copies of the checklists and keep these pages for future use.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
87
Appendix D
Checklists for GuardLogix Safety Applications
Checklist for GuardLogix Controller System
Checklist for GuardLogix System
Company
Site
Safety Function Definition
Fulfilled
Number
System Requirements
1
Are you using only the components listed in
SIL 3-certified GuardLogix Components on page 14 and on the http://www.rockwellautomation.com/
products/certification/safety/ site, with the corresponding firmware release?
2
Have you calculated the system’s safety response time for each safety chain?
3
Does the system’s response time include both the user-defined safety task program watchdog (software
watchdog) time and the safety task rate/period?
4
Is the system response time in proper relation to the process tolerance time?
5
Have probability (PFD/PFH) values been calculated according to the system’s configuration?
6
Have you performed all appropriate functional verification tests?
7
Have you determined how your system will handle faults?
8
Does each network in the safety system have a unique SNN?
9
Is each CIP safety device configured with the correct SNN?
10
Have you generated a safety task signature?
11
Have you uploaded and recorded the safety task signature for future comparison?
12
Following a download, have you verified that the safety task signature in the controller matches the recorded
safety task signature?
13
Do you have an alternate mechanism in place to preserve the safety integrity of the system when making
online edits?
14
Have you taken into consideration the checklists for using SIL inputs and outputs listed on pages 89 and 90?
88
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Yes
No
Comment
Checklists for GuardLogix Safety Applications
Checklist for Safety Inputs
Appendix D
For programming or startup, an individual checklist can be filled in for every
single SIL input channel in a system. This is the only way to make sure that the
requirements are fully and clearly implemented. This checklist can also be used as
documentation on the connection of external wiring to the application program.
Input Checklist for GuardLogix System
Company
Site
Safety Function Definition
SIL Input Channels
Number
Fulfilled
Input Module Requirements
Yes
1
Have you followed installation instructions and precautions to conform to applicable safety standards?
2
Have you performed functional verification tests on the system and modules?
3
Are control, diagnostics, and alarming functions performed in sequence in application logic?
4
Have you uploaded and compared the configuration of each module to the configuration sent by configuration tool?
5
Are modules wired in compliance with PLe/Cat. 4 according to ISO 13849-1?(1)
6
Have you verified that the electrical specifications of the sensor and input are compatible?
No
Comment
(1) For information on wiring your CIP Safety I/O module, refer to the product documentation for your specific module.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
89
Appendix D
Checklists for GuardLogix Safety Applications
Checklist for Safety Outputs
For programming or startup, an individual requirement checklist must be filled in
for every single SIL output channel in a system. This is the only way to make sure
that the requirements are fully and clearly implemented. This checklist can also
be used as documentation on the connection of external wiring to the application
program.
Output Checklist for GuardLogix System
Company
Site
Safety Function Definition
SIL Output Channels
Fulfilled
Number
Output Module Requirements
1
Have you followed installation instructions and precautions to conform to applicable safety standards?
2
Have you performed functional verification tests on the modules?
3
Have you uploaded and compared the configuration of each module to the configuration sent by configuration
tool?
4
Have you verified that test outputs are not used as safety outputs?
5
Are modules wired in compliance with PLe/Cat. 4 according to ISO 13849-1?(1)
6
Have you verified that the electrical specifications of the output and the actuator are compatible?
Yes
(1) For information on wiring your CIP Safety I/O module, refer to the product documentation for your specific module.
90
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
No
Comment
Checklists for GuardLogix Safety Applications
Appendix D
Use the following checklist to help maintain safety when creating or modifying a
safety application program.
Checklist for Developing a
Safety Application Program
Checklist for GuardLogix Application Program Development
Company
Site
Project Definition
Number
Application Program Requirements
1
Are you using version 14, or version 16 or later of RSLogix 5000 software(1), the GuardLogix system
programming software?
2
Were the programming guidelines in Chapter 6 followed during creation of the safety application program?
3
Does the safety application program contain only relay ladder logic?
4
Does the safety application program contain only those instructions listed in Appendix A as suitable for safety
application programming?
5
Does the safety application program clearly differentiate between safety and standard tags?
6
Are only safety tags used for safety routines?
7
Have you verified that safety routines do not attempt to read from or write to standard tags?
8
Have you verified that no safety tags are aliased to standard tags and vice versa?
9
Is each safety output tag correctly configured and connected to a physical output channel?
10
Have you verified that all mapped tags have been conditioned in safety application logic?
11
Have you defined the process parameters that are monitored by fault routines?
12
Have you sealed any safety Add-On Instructions with a instruction signature and recorded the safety
instruction signature?
13
Has the program been reviewed by an independent safety reviewer (if required)?
14
Has the review been documented and signed?
Fulfilled
Yes
No
Comment
(1) RSLogix 5000 software, version 18 or later, supports 1768 Compact GuardLogix controllers.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
91
Appendix D
Checklists for GuardLogix Safety Applications
Notes:
92
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Appendix
E
GuardLogix Systems Safety Data
Topic
Page
PFD Values
93
PFH Values
94
The following examples show probability of failure on demand (PFD) and
probability of failure per hour (PFH) values for GuardLogix 1oo2 SIL 3 systems.
Mission time for GuardLogix controllers and Guard I/O is 20 years.
PFD Values
Figure 22 - Calculated PFD by Functional Test Interval
Calculated PFD
Cat. No.
Description
1756-L6xS and 1756-LSP
GuardLogix Controller
1756-L7xS and 1756-L7SP
GuardLogix controller
5.7E-06
1756-L73SXT and 1756-L7SPXT
GuardLogix XT controller
1768-L43S and 1768-L45S
2 Years
(17,520 hours)
5 Years
(43,800 hours)
10 Years
(87,600 hours)
20 Years
(175,200 hours)
5.5E-06
1.2E-05
1.5E-05
3.5E-05
8.9E-05
5.7E-06
1.5E-05
3.5E-05
8.9E-05
Compact GuardLogix Controller
1.1E-06
2.7E-06
5.7E-06
1.2E-05
1791DS-IB12
CIP Safety 12-point input module
1.754E-06
4.419E-06
8.962E-06
6.013E-06(1)
1791DS-IB16
CIP Safety 16-point input module
1.70E-06
4.25E-06
8.50E-06
1.70E-05
1791DS-IB8XOB8
CIP Safety 8-point input/ 8-point output module
1.755E-06
4.421E-06
8.963E-06
6.013E-06(1)
1791DS-IB4XOW4
CIP Safety 4-point input/4-point relay output module
4.151E-05
1.207E-04
2.978E-04
7.684E-04(1)
1791DS-IB8XOBV4
CIP Safety 8-point input/4 bi-polar output module
1.75E-06
4.37E-06
8.74E-06
1.75E-05
1732DS-IB8
CIP Safety 8-point input module
1.70E-06
4.25E-06
8.50E-06
1.70E-05
1791ES-IB16
CIP Safety 16-point input module
1.65E-06
4.14E-06
8.27E-06
1.65E-05
1791ES-IB8XOBV4
CIP Safety 8-point input/4 bi-polar output module
1.70E-06
4.26E-06
8.51E-06
1.70E-05
1734-IB8S
CIP Safety 8-point input module
1.17E-06
2.93E-06
5.86E-06
1.17E-05
1734-OB8S
CIP Safety 8-point output module
1.21E-06
3.03E-06
6.06E-06
1.21E-05
1734-IE4S
CIP Safety 4-point analog input module
3.2E-07
8.1E-07
1.6E-06
3.3E-06
Not applicable
1732DS-IB8XOBV4
(1) The 20-year PFD data for this product applies only to product with a manufacture date code of 2009/01/01
(January 1, 2009) or later. See the product label for the date code.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
93
Appendix E
GuardLogix Systems Safety Data
PFH Values
The data below applies to proof test intervals up to and including 20 years.
Figure 23 - PFH Calculations
Cat. No.
Description
PFH (1/Hour)
1756-L6xS and 1756-LSP
GuardLogix controller
2.0E-10
1756-L7xS and 1756-L7SP
GuardLogix controller
1.2E-09
1756-L7xSXT and 1756-L7SPXT
GuardLogix XT controller
1.2E-09
1768-L43S and 1768-L45S
Compact GuardLogix controller
2.0E-10
1791DS-IB12
CIP Safety 12-point input module
6.84E-11(1)
1791DS-IB16
CIP Safety 16-point input module
1.94E-10
1791DS-IB8XOB8
CIP Safety 8-point input/ 8-point output module
6.84E-11(1)
1791DS-IB4XOW4
CIP Safety 4-point input/4-point relay output module
4.072E-09(1)
1791DS-IB8XOBV4
CIP Safety 8-point input/4 bi-polar output module
2.00E-10
1732DS-IB8
CIP Safety 8-point input module
1.94E-10
1791ES-IB16
CIP Safety 16-point input module
1.89E-10
1791ES-IB8XOBV4
CIP Safety 8-point input/4 bi-polar output module
1.94E-10
1734-IB8S
CIP Safety 8-point input module
1.34E-10
1734-OB8S
CIP Safety 8-point output module
1.38E-10
1734-IE4S
CIP Safety 4-point analog input module
3.9E-11
1732DS-IB8XOBV4
(1) The PFH data for this product applies only to product with a manufacture date code of 2009/01/01 (January 1, 2009) or later. See the product label for the date code.
94
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Appendix
F
RSLogix 5000 Software, Version 14 and Later,
Safety Application Instructions
Topic
Page
De-energize to Trip System
95
Use Connection Status Data to Initiate a Fault Programmatically
95
De-energize to Trip System
When using RSLogix 5000 software, version 14 safety application instructions,
all inputs and outputs are set to zero when a fault is detected. As a result, any
inputs being monitored by one of the diverse input instructions (Diverse Inputs
or Two-hand Run Station) should have normally-closed inputs conditioned by
logic similar to the logic in Rung 4 of Ladder Logic Example 2 and Ladder Logic
Example 3 on pages 98 and 99. The exact logic required is both application and
input-module dependent. However, the logic must create a safety state of 1 for
the normally-closed input of the diverse input instructions.
Use Connection Status Data
to Initiate a Fault
Programmatically
The following diagrams provide examples of the application logic required to
latch and reset I/O failures. The examples show the logic necessary for input only
modules, as well as input and output combination modules. The examples use a
feature of the I/O modules called Combined Status, which presents the status of
all of the input channels in a single boolean variable. Another boolean variable
represents the status of all the output channels. This approach reduces the
amount of I/O conditioning logic required and forces the logic to shut down all
input or output channels on the affected module.
Use the Input Fault Latch and Reset Flow Chart on page 96 to determine which
rungs of logic are required for different application situations. Ladder Logic
Example 1 shows logic that overwrites the actual input tag variables while a fault
condition exists. If the actual input state is required for troubleshooting while the
input failure is latched, use the logic shown in Ladder Logic Example 2. This
logic uses internal tags that represent the inputs to be used in the application
logic. While the input failure is latched, the internal tags are set to their safety
state. While the input failure is not latched, the actual input values are copied to
the internal tags.
Use the Output Fault Latch and Reset Flowchart to determine which rungs of
application logic in Ladder Logic Example 3 on page 99 are required.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
95
Appendix F
RSLogix 5000 Software, Version 14 and Later, Safety Application Instructions
Figure 24 - Input Fault Latch and Reset Flow Chart
Start
Does this safety function require operator
intervention after a safety input failure?
No
Yes
No
Are the inputs used to drive
safety application instructions?
Yes
Can Circuit Reset be used for operator
intervention?
Make sure you select
Manual Reset for the safety
application instruction.
Yes
No
Write logic to latch input failure.
(Example Rung 0)
Write logic to set inputs to safety state.
(Example Rungs 2 and 3)
Yes
No
Write logic to latch input failure.
(Example Rung 0)
Write logic to unlatch input failure.
(Example Rung 1)
No
Are any inputs used in an
instruction with diverse inputs?
(DIN or THRS)
Yes
Write logic to set safety state value when input is
faulted. (Example Rung 4)
Done
96
Is input fault information required for
diagnostic purposes?
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
RSLogix 5000 Software, Version 14 and Later, Safety Application Instructions
Appendix F
Figure 25 - Ladder Logic Example 1
Node 30 is an 8-point input/8-point output combination module.
Node 31 is a 12-point input module.
If the input status is not OK, then latch the inputs faulted indication.
0
Node30:I.InputStatus
/
Node30InputsFaulted
L
Node31:I.CombinedStatus
/
Node31InputsFaulted
L
If the raising edge of the fault reset signal is detected and the input status is OK, then unlatch the inputs faulted indication.
FaultReset
1
InputFaultResetOneShot
ONS
Node30:I.InputStatus
Node30InputsFaulted
U
Node31:I.CombinedStatus
Node31InputsFaulted
U
If the inputs are faulted, then overwrite the input tags with safety state values.
Node30InputsFaulted
Node30:I.Pt00Data
U
2
Node30:I.Pt01Data
U
Node30:I.Pt07Data
U
If the inputs are faulted, then overwrite the input tags with safety state values.
Node31InputsFaulted
Node31:I.Pt00Data
U
3
Node31:I.Pt01Data
U
Node31:I.Pt11Data
U
If the inputs faulted indication is true, then set the Diverse input values to their safety state (1).
Node30InputsFaulted
Node30:I.Pt01Data
L
4
Node30:I.Pt03Data
L
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
97
Appendix F
RSLogix 5000 Software, Version 14 and Later, Safety Application Instructions
Figure 26 - Ladder Logic Example 2
Node 30 is an 8-point input/8-point output combination module.
Node 31 is a 12-point input module.
If the input status is not OK, then latch the inputs faulted indication.
0
Node30:I.InputStatus
/
Node30InputsFaulted
L
Node31:I.CombinedStatus
/
Node31InputsFaulted
L
If the raising edge of the fault reset signal is detected and the input status is OK, then unlatch the inputs faulted indication.
FaultReset
1
InputFaultResetOneShot
ONS
Node30:I.InputStatus
Node30InputsFaulted
U
Node31:I.CombinedStatus
Node31InputsFaulted
U
If the inputs are not faulted, then write the input tag values to the internal representations of the inputs.
2
Node30:I.Pt00Data Node30Input00
Node30InputsFaulted
/
Node30:I.Pt01Data
Node30Input01
Node30:I.Pt07Data
Node30Input07
If the inputs are not faulted, then write the input tag values to the internal representations of the inputs.
3
Node31:I.Pt00Data Node31Input00
Node31InputsFaulted
/
Node31:I.Pt01Data
Node31Input01
Node31:I.Pt11Data
Node31Input11
If the inputs faulted indication is true, then set the internal representations of the Diverse inputs to their safety state (1).
Node30InputsFaulted
Node31Input01
L
4
Node31Input03
L
98
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
RSLogix 5000 Software, Version 14 and Later, Safety Application Instructions
Appendix F
Figure 27 - Output Fault Latch and Reset Flowchart
Start
Does this safety function require operator
intervention after a safety output failure?
No
Yes
Yes
Write logic to latch output failure.
(Example Rung 0)
Is output fault information required for
diagnostic purposes?
No
Write logic to set outputs to a safety
state. (Example Rung 2)
Write logic to latch output failure.
(Example Rung 0)
Write logic to unlatch output failure
(Example Rung 1)
Done
Figure 28 - Ladder Logic Example 3
Node 30 is an 8-point input/8-point output combination module.
If the output status is not OK, then latch the output faulted indication.
0
Node30:I.OutputStatus
/
Node30OutputsFaulted
L
If the raising edge of the fault reset signal is detected and the input status is OK, then unlatch the inputs faulted indication.
FaultReset
1
2
InputFaultResetOneShot
ONS
Node30OutputsFaulted
/
Node30:I.OutputStatus
Node30OutputsFaulted
U
RedundantOutputTag.O1 Node30:O.Pt00Data
RedundantOutputTag.O2 Node30:O.Pt01Data
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
99
Appendix F
RSLogix 5000 Software, Version 14 and Later, Safety Application Instructions
Notes:
100
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Appendix
G
Using 1794 FLEX I/O Modules and 1756 SIL 2
Inputs and Outputs with 1756 GuardLogix
Controllers to Comply with EN 50156
Topic
Page
SIL 2 Dual-channel Inputs (standard side of 1756 GuardLogix controllers)
101
SIL 2 Outputs Using SIL 3 Guard I/O Output Modules
103
SIL 2 Outputs Using 1756 or 1794 SIL 2 Output Modules
103
Safety Functions within the 1756 GuardLogix Safety Task
104
Dual-channel configuration is required for compliance in certain safety-related
applications, including burner-related safety functions. These examples provide
guidelines for satisfying EN50156 SIL 2 dual-channel requirements with 1- and
2-year proof test intervals.
SIL 2 Dual-channel Inputs
(standard side of 1756
GuardLogix controllers)
You must implement clear and easily-identifiable separation between both input
channels and adhere to all existing SIL 2 requirements as defined in Using
ControlLogix in SIL 2 Applications, publication 1756-RM001.
Figure 29 - SIL 2 Dual-channel Inputs Example F
Channel A
Channel B
Ch0+
Ch0+
+
Ch0-
Ch0-
-
Voltage
Transmitter A
+
Voltage
Transmitter B
-
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
101
Appendix G
Using 1794 FLEX I/O Modules and 1756 SIL 2 Inputs and Outputs with 1756 GuardLogix Controllers to Comply with EN 50156
SIL 2 Input Data
Keep channel A and
channel B input data
separate at all times. This
example illustrates one
method for separating
channel A and channel B
data in your application.
Any logic processing that
needs to occur must follow
ControlLogix SIL 2
guidelines.
• Follow all rules for 1756 I/O modules as defined in the Using
ControlLogix in SIL 2 Applications Safety Reference Manual, publication
1756-RM001.
• Follow all rules for 1794 FLEX I/O modules as defined in the FLEX I/O
System with ControlLogix for SIL 2 Safety Reference Manual, publication
1794-RM001.
IMPORTANT
Do not perform safety-specific functions within these routines. Safety
evaluation must be handled within the 1756 GuardLogix safety task.
Transferring SIL 2 Data Into the Safety Task
To transfer channel A and channel B SIL 2 safety data into the GuardLogix safety
task, use the safety tag mapping functionality in RSLogix 5000 software. The tag
names used here are for example purposes. Implement and follow naming
conventions that are appropriate for your application.
TIP
102
To use the safety tag mapping feature, select Map Safety Tags from the
Logic menu in RSLogix 5000 software.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Using 1794 FLEX I/O Modules and 1756 SIL 2 Inputs and Outputs with 1756 GuardLogix Controllers to Comply with EN 50156
Appendix G
SIL 2 Outputs Using SIL 3
Guard I/O Output Modules
Follow these guidelines for SIL 2 outputs:
SIL 2 Outputs Using 1756 or
1794 SIL 2 Output Modules
When using these SIL 2-rated output modules, you are required to configure
your SIL 2 safety outputs as GuardLogix-produced safety tags to comply with the
dual-channel requirements of EN 50156.
• Guard I/O output modules used for SIL 2 safety outputs must be
configured for dual-channel operation.
• All Guard I/O output modules are approved for use in SIL 2 applications.
– 1732DS-IB8XOBV4
– 1791ES-IB8XOBV4
– 1791DS-IB8XOBV4, 1791ES-IB8XOBV4
– 1791DS-IB4XOW4
– 1791DS-IB8XOB8
– 1734-OB8S
Create produced safety tags with the SIL 2 outputs that your application
requires. GuardLogix produced/consumed safety tags require the first member to
be allocated for diagnostics. The first member of a produced/consumed safety
connection must be a data type called CONNECTION_STATUS. This
example shows a SIL 2 tag with two INT and two BOOL members. Use these
SIL 2 safety tags to directly control the 1756 or 1794 SIL 2 outputs.
TIP
In this example, a consumer for the produced tag is not shown. The connection
status will show faulted if you don't configure a consumer. However, in this
type of configuration, you are not required to monitor the connection status of
the produced tag so the fault is not a concern.
• Follow all rules for 1756 I/O modules as defined in the Using
ControlLogix in SIL 2 Applications Safety Reference Manual, publication
1756-RM001.
• Follow all rules for 1794 FLEX I/O modules as defined in the FLEX I/O
System with ControlLogix for SIL 2 Safety Reference Manual, publication
1794-RM001.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
103
Appendix G
Using 1794 FLEX I/O Modules and 1756 SIL 2 Inputs and Outputs with 1756 GuardLogix Controllers to Comply with EN 50156
Safety Functions within the
1756 GuardLogix Safety Task
Follow these guidelines for using SIL 2 and SIL 3 safety functions within the
safety task:
• All available safety application instructions may be used.
• SIL 3 safety input modules (that is, Guard I/O modules) may be used with
single-channel configuration for SIL 2 safety functions.
• Use of the safety task signature and safety-locking the application is
recommended.
IMPORTANT
104
You must not use SIL 2 data to directly control a SIL 3 output.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Glossary
The following terms and abbreviations are used throughout this manual. For
definitions of terms not listed here, refer to the Allen-Bradley Industrial
Automation Glossary, publication AG-7.1.
Add-On Instruction An instruction that you create as an add-on to the Logix instruction set. Once
defined, an Add-On Instruction can be used like any other Logix instruction and
can be used across various projects. An Add-On Instruction is composed of
parameters, local tags, logic routine, and optional scan mode routines.
Assemble Edits You assemble edits when you have made online edit changes to the controller
program and want the changes to become permanent because you can test,
un-test, or cancel the edits.
Cancel Edits Action taken to reject any unassembled online edit changes.
CIP Safety Protocol A network communication method designed and certified for transport of data
with high integrity.
Configuration Signature A unique number that identifies a device’s configuration. The configuration
signature is made up of an ID number, date, and time.
Instruction Signature The instruction signature consists of an ID number and date/timestamp that
identifies the contents of the Add-On Instruction definition at a given point in
time.
Nonrecoverable Controller Fault A fault that forces all processing to be terminated and requires controller power
to be cycled from off to on. The user program is not preserved and must be
redownloaded.
Nonrecoverable Safety Fault A fault, which even though properly handled by the fault handling mechanisms
provided by the safety controller and implemented by the user, terminates all
safety task processing, and requires external user action to restart the safety task.
Online Situation where you are monitoring/modifying the program in the controller.
Overlap When a task (periodic or event) is triggered while the task is still executing from
the previous trigger.
Partnership The primary controller and safety partner must both be present, and the
hardware and firmware must be compatible for partnership to be established.
Pending Edit A change to a routine that has been made in RSLogix 5000 software, but has not
yet been communicated to the controller by accepting the edit.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
105
Preface
Periodic Task A task that is triggered by the operating system at a repetitive period of time.
Whenever the time expires, the task is triggered and its programs are executed.
Data and outputs established by the programs in the task retain their values until
the next execution of the task or until they are manipulated by another task.
Periodic tasks always interrupt the continuous task.
Primary Controller The processor in a dual-processor controller that performs standard controller
functionality and communicates with the safety partner to perform safety-related
functions.
Recoverable Fault A fault, which when properly handled by implementing the fault handling
mechanisms provided by the controller, does not force user logic execution to be
terminated.
Requested Packet Interval (RPI) When communicating over a network, this is the maximum amount of time
between subsequent production of input data.
Routine A set of logic instructions in a single programming language, such as a ladder
diagram. Routines provide executable code for the project in a controller. Each
program has a main routine. You can also specify optional routines.
Safety Add-On Instruction An Add-On Instruction that can use safety application instructions. In addition
to the instruction signature used for high-integrity Add-On Instructions, safety
Add-On Instructions feature a SIL 3 safety instruction signature for use in safetyrelated functions.
Safety Application Instructions Safety Instructions that provide safety-related functionality. They have been
certified to SIL 3 for use in safety routines.
Safety Component Any object, task, program, routine, tag, or module that is marked as a safetyrelated item.
Safety Instruction Signature The safety instruction signature is an ID number that identifies the execution
characteristics of the safety Add-On Instruction. It is used to verify the integrity
of the safety Add-On Instruction during downloads to the controller.
Safety I/O Safety I/O has most of the attributes of standard I/O except it features
mechanisms certified to SIL 3 for data integrity.
Safety Network Number (SNN) Uniquely identifies a network across all networks in the safety system. The end
user is responsible is responsible for assigning a unique number for each safety
network or safety subnet within a system. The safety network number makes up
part of the Unique Node Identifier (UNID).
Safety Partner The processor in a dual-processor controller that works with the primary
controller to perform safety-related functions.
106
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Preface
Safety Program A safety program has all the attributes of a standard program, except that it can be
scheduled only in a safety task. The safety program consists of zero or more safety
routines. It cannot contain standard routines or standard tags.
Safety Routine A safety routine has all the attributes of a standard routine except that it is valid
only in a safety program and that it consists of one or more instructions suitable
for safety applications. (See Appendix A for a list of Safety Application
Instructions and standard Logix Instructions that may be used in safety routine
logic.)
Safety Tags A safety tag has all the attributes of a standard tag except that the GuardLogix
controller provides mechanisms certified to SIL 3 to ensure the integrity of their
associated data. They can be program-scoped or controller-scoped.
Safety Task A safety task has all the attributes of a standard task except that it is valid only in a
GuardLogix controller and that it may schedule only safety programs. Only one
safety task can exist in a GuardLogix controller. The safety task must be a
periodic/timed task.
Safety Task Period The period at which the safety task executes.
Safety Task Reaction Time The sum of the safety task period plus the safety task watchdog. This time
represents the worst case delay from any input change presented to the
GuardLogix controller until the processed output is available to the producing
connection.
Safety Task Signature A value, calculated by the firmware, that uniquely represents the logic and
configuration of the safety system. It is used to verify the integrity of the safety
application program during downloads to the controller.
Safety Task Watchdog The maximum time allowed from the start of safety task execution to its
completion. Exceeding the safety task Watchdog triggers a nonrecoverable safety
fault.
Standard Component Any object, task, tag, program, and so on, that is not marked as being a safetyrelated item.
Standard Controller As used in this document, standard controller refers generically to a
ControlLogix controller.
Symbolic Addressing A method of addressing that provides an ASCII interpretation of the tag name.
System Reaction Time The worst case time from a safety-related event as input to the system or as a fault
within the system, until the time that the system is in the safe state. System
Reaction Time includes sensor and activator Reaction Times as well as the
Controller Reaction Time.
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
107
Preface
Task A scheduling mechanism for executing a program. A task provides scheduling
and priority information for a set of one or more programs that execute based on
a certain criteria. Once a task is triggered (activated), all of the programs assigned
(scheduled) to the task execute in the order in which they are displayed in the
controller organizer.
Timeout Multiplier This value determines the number of messages that may be lost before declaring a
connection error.
Valid Connection Safety connection is open and active, with no errors.
108
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Index
Numerics
1734-AENT 15, 16, 24
1734-AENTR 16
1756-A10 15
1756-A13 15
1756-A17 15
1756-A4 15
1756-A5XT 15
1756-A7 15
1756-A7XT 15
1756-CN2 15, 24
1756-CN2R 15, 24
1756-CN2RXT 15, 24
1756-DNB 15, 24
1756-EN2F 15, 24
1756-EN2T 15, 24
1756-EN2TR 24
1756-EN2TXT 15, 24
1756-EN3TR 24
1756-ENBT 15, 24
1756-PB72 15
1756-PB75 15
1768-CNB 16, 24
1768-CNBR 24
1768-ENBT 16, 24
1768-PA3 16
1768-PB3 16
1784-CF128 15, 16
1784-SD1 15
1784-SD2 15
checklist
GuardLogix controller system 26, 88
program development 91
SIL 3 inputs 89
SIL 3 outputs 90
CIP Safety protocol
definition 105
overview 23
routable system 33
commissioning life cycle 51
communication modules
catalog numbers 15
hardware overview 24
CompactFlash card 16
configuration signature 29
connection status 64
CONNECTION_STATUS
data type 63
control and information protocol
Definition 9
control function
specification 52
ControlNet bridge module
hardware overview 24
D
DeviceNet Safety
communication overview 25
DeviceNet scanner interface module
hardware overview 24
diagnostic coverage
definition 9
E
A
Add-On Instruction
certify 73
instruction signature 75
safety instruction signature 76
agency certifications 16
application development basics 50
application program
See program
EN50156 101
EN954-1
CAT 4 9, 11
EtherNet/IP
communication overview 24
EtherNet/IP communication interface module
hardware overview 24
European norm.
definition 9
B
F
burner-related safety functions 101
C
certifications 16
chassis
catalog numbers 15
hardware overview 22
faults
nonrecoverable controller faults 66
nonrecoverable safety faults 66
overriding 66
recoverable 67, 106
firmware revisions 15, 16
forcing 58
functional verification tests 12
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
109
Index
G
get system value (GSV)
defintion 9
GSV instructions 65
Guard I/O modules
SIL 2 applications 103
H
hard faults
recovery 66
human-to-machine interfaces
use and application 43-45
I
I/O modules
replacement 29-31
IEC 61508
Safety Integrity Level 3 (SIL 3) certification 9,
11, 76
inhibiting a module 58
installing a controller 21
instruction signature 75
definition 105
instructions
safety 71
safety application 69
interface
HMI use and application 43-45
ISO 13849-1 9, 11
L
ladder logic safety instructions 71
Logix components
SIL 3-certified 14
Logix system reaction time
calculating 80
output delay time 28
overlap
definition 105
ownership 29
P
partnership
definition 105
peer-to-peer communication 24
pending edits 57
Performance Level
definition 9
period task
definition 106
PLe 9, 11
power supplies 15
hardware overview 22
primary controller
definition 106
hardware overview 22
probability of failure on demand (PFD) 16-17
definition 9
probability of failure per hour (PFH) 16-17
definition 9
program
checklist 91
download 57
editing life cycle 61
indentification 53
offline editing 60
online editing 60
upload 57
verification 54
programming software 11
project
confirmation 55
proof tests 12
see functional verification tests
Q
M
qualifying standard data 47
mapping tags 47
memory card 15, 16
metal form instructions 70
N
nonrecoverable controller faults 66, 105
nonrecoverable safety faults 66, 105
restarting the safety task 66
O
offline edits 60
online
definition 105
online editing 57, 60
110
R
reaction time
calculating for system 79
safety task 18
system 18, 107
recoverable faults 67, 106
reliability burden 17
requested packet interval
definition 106
range 42
RSLogix 5000 software
changing your application program 59
commissioning life cycle 51
version 15, 16
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Index
S
safety application instructions 69
definition 106
safety certifications and compliances 16
safety concept
assumptions 49
safety consumed tags
safety network number 35
safety functions
CIP Safety I/O 27
Safety Output 28
safety instruction signature 76
definition 106
Safety Integrity Level (SIL)
compliance distribution and weight 17
function example 14
policy 11-19
Safety Integrity Level (SIL) 3 certification
Logix components 14
TÜV Rheinland 12
user responsibilities 12
Safety Integrity Level 3 (SIL 3) certification 9,
11, 76
safety network number 34
definition 106
manual assignment 34
out-of-box modules 36
safety consumed tags 35
safety partner
configuration 22
definition 106
hardware overview 22
location 22
safety program 45
definition 107
safety routine 45
definition 107
safety tags 46
definition 107
valid data types 46
safety task
definition 107
execution 42
overview 41
priority 84
reaction time 18, 107
watchdog time 84
safety task period 19
definition 107
limitations 41
overview 19
safety task signature
definition 107
deleting 54
generating 53
restricted operations 54
safety task watchdog 19
definition 107
modifying 19
overview 19
setting via RSLogix 5000 19
timeout 41
safety-locking 56
default 56
passwords 56
restricted operations 56
Secure Digital (SD) card 15
set system variable (SSV) instruction 65
signature history 77
SIL 2
EN50156 101
software
changing your application program 59
commissioning life cycle 51
system reaction time 18
calculating 79
T
tags
produced/consumed safety data 46
Safety I/O 46
see also safety tags
terminology 9
timeout multiplier 82
definition 108
U
unique node reference
defined 34
W
watchdog time 84
X
XT-components 15
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
111
Index
112
Rockwell Automation Publication 1756-RM093H-EN-P - August 2012
Rockwell Automation Support
Rockwell Automation provides technical information on the Web to assist you in using its products.
At http://www.rockwellautomation.com/support/, you can find technical manuals, a knowledge base of FAQs, technical and
application notes, sample code and links to software service packs, and a MySupport feature that you can customize to
make the best use of these tools.
For an additional level of technical phone support for installation, configuration, and troubleshooting, we offer
TechConnect support programs. For more information, contact your local distributor or Rockwell Automation
representative, or visit http://www.rockwellautomation.com/support/.
Installation Assistance
If you experience a problem within the first 24 hours of installation, review the information that is contained in this
manual. You can contact Customer Support for initial help in getting your product up and running.
United States or Canada
1.440.646.3434
Outside United States or Canada
Use the Worldwide Locator at http://www.rockwellautomation.com/support/americas/phone_en.html, or contact your local Rockwell
Automation representative.
New Product Satisfaction Return
Rockwell Automation tests all of its products to ensure that they are fully operational when shipped from the
manufacturing facility. However, if your product is not functioning and needs to be returned, follow these procedures.
United States
Contact your distributor. You must provide a Customer Support case number (call the phone number above to obtain one) to your
distributor to complete the return process.
Outside United States
Please contact your local Rockwell Automation representative for the return procedure.
Documentation Feedback
Your comments will help us serve your documentation needs better. If you have any suggestions on how to improve this
document, complete this form, publication RA-DU002, available at http://www.rockwellautomation.com/literature/.
Riga
tel. +371 6738 1617
[email protected]
Helsinki
tel. +358 9 540 4940
[email protected]
St. Petersburg
tel. +7 812 327 3752
[email protected]
Moscow
tel. +7 495 641 1616
[email protected]
Yekaterinburg
tel. +7 343 287 19 19
[email protected]
Samara
tel. +7 846 273 95 85
[email protected]
Кiev
tel. +38 044 495 33 40
[email protected]
Vilnius
tel. +370 5 215 1646
[email protected]
Tallinn
tel. +372 668 4500
[email protected]
Мinsk
tel. +375 17 200 0876
[email protected]
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF

advertisement