Allen-Bradley 1756-L6 Series, Reference Manual, Page: 38 / 134

38 Rockwell Automation Publication 1756-RM001I-EN-P - May 2012
Chapter 4 ControlLogix Communication Modules
Peer-to-Peer Communication
Requirements Peer-to-peer communication via a ControlNet or EtherNet/IP network is
permitted when these requirements are met:
• Non-SIL 2 controllers can read data from SIL 2 controllers by directly
reading the data or by consuming data from a SIL 2 controller that is
configured to produce data.
• Controllers within the safety loop can be configured to:
– consume safety data from other safety controllers within the safety
loop.
– consume nonsafety data from outside the safety loop, such as a reset
signal.
– produce data to controllers outside the safety loop.
• Programming that verifies the correct reception of data must be used.
When producing or consuming SIL 2 safety data, you must use two
independent data paths between the SIL 2 devices. For example, to
exchange SIL 2 data between two ControlLogix SIL 2 controllers, you
could use two produced connections sending data to two consume
connections. Each controller produces data to the other.
Additional Resources This table lists additional resources specific to the ControlLogix communication
modules.
You can view or download Rockwell Automation publications at
http://www.rockwellautomation.com/literature/ .
Cat. No. Module Description User Manual
1756-CNB, 1756-CN2 ControlNet Communication Module CNET-UM001
1756-CNBR,
1756-CN2R Redundant ControlNet Communication Module
1756-DHRIO Data Highway Plus - Remote I/O Communication Interface
Module 1756-UM514
1756-DNB DeviceNet Scanner Module DNET-UM004
1756-ENBT
1756-EN2T
1756-EN2TR EtherNet Communication Module ENET-UM001
1756-RM Redundancy Module 1756-UM535
1756-SYNCH SynchLink Module 1756-UM521