User manual

35Publication 1756-RM093F-EN-P - January 2010 35
Chapter 4
CIP Safety and the Safety Network Number
Introduction
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 Routable CIP Safety
Control System
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.
CIP Safety System Example
Topic Page
The Routable CIP Safety Control System 35
Considerations for Assigning the Safety Network Number (SNN) 38
1756-L62S
1756-LSP
1756-DNB
1756-ENBT
1768-PB3
1768-L43S
1769-ECR
Switch
Switch
Router/
Firewall
(1)
CIP Safety I/O
SmartGuard
1756-IB16
1756-DNB
1756-ENBT
(1) The router or firewall is set up to limit traffic.
1756-OB16
1768-ENBT 1768-ENBT
CIP Safety I/O
CIP Safety I/O
CIP Safety I/O
CIP Safety I/O
CIP Safety I/O
CIP Safety I/O
CIP Safety I/O