Allen-Bradley 1756 Series, User Manual, Page: 59 / 136

Rockwell Automation Publication 1756-UM013B-EN-P - October 2019 59
1756-OBV8S Output Module Features Chapter 4
Safety Application
Suitability Level
Table 13 describes the safety application suitability levels for the 1756-OBV8S
module.
Table 13 - Safety Application Suitability for 1756-OBV8S Module
Suitability Level Conditions Notes
Safety applications that are rated up to, and
including,
SIL CL3, PLd, Cat. 2 as defined in IEC
61508, IEC 61511, IEC 62061, and ISO 13849-1.
The safety function uses single -channel
mode.
• Module Output Mode is Sourcing
• Module channel Point Operation Type is
SINGLE
• Module channel Point mode is Safety Pulse
test.
The safety function uses single-channel mode
• Module Output Mode is bipolar
• Module channel Point mode is Safety Pulse
test
Consider the following:
• Single-channel mode refers to a single-channel actuator subsystem
driven by one sourcing output channel configured for SINGLE, or one
bipolar output channel configured for SINGLE.
• Dual channel mode refers to a dual channel actuator subsystem driven
by two sourcing output channels configured for DUAL, or one bipolar
output channel configured for SINGLE.
• The 1756-OBV8S module is capable of being a SIL CL3/PLe/Cat. 4
subsystem (SRP/CS) when either a single-channel or dual-channel
safety device is wired to the output channels.
• The channel mode type, that is, single or dual, affects Category and
Performance Level. You can use the modules in SIL CL3, PLe
applications regardless of channel mode type.
The determining factor to whether a 1756 ControlLogix digital safety
I/O module resides in a SIL CL3, PLe, Cat. 4 safety application is that the
overall safety architecture be a dual-channel system.
• The requirement that Point Mode be Safety Pulse Test assumes that
only the safety modules provide diagnostics to a specific Suitability
Level.
The larger safety system within which the safety I/O module resides
can provide the diagnostics necessary to achieve the stated Suitability
Level without the requirement that Point Mode be Safety Pulse Test.
Safety applications that are rated up to, and
including,
SIL CL3, PLe, Cat. 4 as defined in IEC
61508, IEC 61511, IEC 62061, and ISO 13849-1.
The safety function uses dual-channel mode.
• Module Output Mode is Sourcing
• Module Channel Point Operation Type is
DUAL
• Module channel Point mode is Safety Pulse
test.
The safety function uses dual-channel mode
• Module Output Mode is bipolar
• Module channel Point mode is Safety Pulse
test