Rockwell Automation 1756-SPESMNRMXT GuardLogix Controllers User Manual - Manuel (Page 97)

Rockwell Automation Publication 1756-UM020I-EN-P - August 2012 97
Develop Safety Applications Chapter 6
Produced/Consumed Safety
Tags To transfer safety data between GuardLogix controllers, you use produced and
consumed safety tags. Produced and consumed tags require connections. The
default connection type for produced and consumed tags is unicast in version 19
and later of RSLogix 5000 software.
Produced and consumed safety tags are subject to the following restrictions:
• Only controller-scoped safety tags can be shared.
• Produced and consumed safety tags are limited to 128 bytes.
• Produced/consumed tag pairs must be of the same user-defined data type.
• The first member of that user-defined data type must be the predefined
CONNECTION_STATUS data type.
• The requested packet interval (RPI) of the consumed safety tag must
match the safety task period of the producing GuardLogix controller.
To properly configure produced and consumed safety tags to share data between
peer safety controllers, you must properly configure the peer safety controllers,
produce a safety tag, and consume a safety tag, as described below.
Configure the Peer Safety Controllers’ Safety Network Numbers
The peer safety controller is subject to the same configuration requirements as
the local safety controller. The peer safety controller must also have a safety
network number (SNN). The SNN of the peer safety controller depends upon
its placement in the system.
Table 29 - Produced and Consumed Connections
Tag Connection Description
Produced A GuardLogix controller can produce (send) safety tags to other 1756 or 1768 GuardLogix
controllers.
The producing controller uses a single connection for each consumer.
Consumed GuardLogix controllers can consume (receive) safety tags from other 1756 or 1768 GuardLogix
controllers.
Each consumed tag consumes one connection.
Table 30 - SNN and Controller Placement
Peer Safety Controller Location SNN
Placed in the local chassis GuardLogix controllers located in a common chassis
should have the same SNN.
Placed in another chassis The controller must have a unique SNN.