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Rockwell Automation Publication 1769-UM022C-EN-P - June 2018
Chapter 5
Communicate Over Networks
Managing the Safety Network Number (SNN)
The SNN assigned to safety devices on a network segment must be unique.
You must be sure that a unique SNN is assigned to each CIP Safety network
that contains safety devices.
The SNN assigned to safety devices on a network segment must be unique.
You must be sure that a unique SNN is assigned to each CIP Safety network
that contains safety devices.
The SNN can be software-assigned (time-based) or user-assigned (manual).
These two formats of the SNN are described in the following sections.
Time-based SNN
If the time-based format is selected, the SNN value that is generated represents
the date and time at which the number was generated, according to the
personal computer running the configuration software.
Figure 7 - Time-based SNN Format
TIP
Multiple safety network numbers can be assigned to a CIP Safety subnet or a
ControlBus™ chassis that contains more than one safety device.