Allen-Bradley GuardLogix 5570

Rockwell Automation Publication 1756-UM022D-EN-P - May 2017 59
Communicate over Networks Chapter 4
Manual Safety Network Number
If the manual format is selected, the SNN is entered as values from 1…9999
decimal.
Figure 12 - Manual Entry
Assign the Safety Network Number (SNN)
You can allow the Logix Designer application to automatically assign an SNN,
or you can assign the SNN manually.
Automatic Assignment
When a new controller or device is created, a time-based SNN is automatically
assigned. Subsequent new safety device additions to the same CIP safety network
are assigned the same SNN defined within the lowest address on that CIP safety
network.
Manual Assignment
The manual option is intended for routable CIP safety systems where the
number of network subnets and interconnecting networks is small, and where
you can manage and assign the SNN in a logical manner for your specific
application.
See
Change the Safety Network Number (SNN) on page 60.
IMPORTANT If you assign an SNN manually, make sure that system expansion does not
result in a duplication of SNN and node address combinations.
In Logix Designer version 24, a verification error occurs if your project
contains duplicate SNN and node address combinations.
In Logix Designer version 26, a warning appears if your project contains
duplicate SNN and node address combinations. You can still verify the project
but Rockwell Automation recommends that you resolve the duplicate
combinations.