Change the Safety Network Number (SNN)

The CIP Safety protocol is an end-node to end-node safety protocol that allows routing of CIP Safety messages to and from CIP Safety devices through bridges, switches, and routers. To prevent errors in non-certified bridges, switches, or routers from becoming dangerous, each end node port that is within a routable CIP Safety control system must have a unique node reference. This unique reference is a combination of a Safety Network Number (SNN) and the node address.
A time-based Safety Network Number is automatically assigned by the software when the safety project is created or when changing the IP Mode for
CompactLogix
 5380 controllers. The time-based format is based on the creation date and time (to the millisecond). The Safety Network Number can also be entered manually.
Use the
Safety
 tab on the
Controller Properties
 dialog box to view or change the Safety Network Number. The
Safety
 tab displays the safety network number for each port that supports a CIP Safety connection. Some controllers, such as the
GuardLogix
 5580 and
CompactLogix
 5380, may have multiple Safety ports.
Before you begin:
  • Unlock the project if it is safety-locked.
  • Delete the safety signature if a safety signature exists.
To change the SNN:
  1. On the
    Online
     toolbar, select the
    Controller Properties
     icon.
  2. In the
    Controller Properties
     dialog box, select the
    Safety
     tab.
  3. Select Browse button to the right of the
    Safety Network Number
     to change. The
    Safety Network Number
     dialog box opens.
  4. Do one of these actions:
    • Select
      Time-based
       and then select
      Generate
       to have the software assign the SNN.
    • Select
      Manual
       and then enter a number between 1 and 9999.
      The Safety Network Number appears in the
      Number
       box.
  5. Select
    OK
    .
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