Manual Assignment of Safety Network Number
Manual assignment is useful if you lay out your network and put the SNNs on your network diagram. It may be easier to read SNNs from a diagram than it is to copy and paste them from multiple projects.
Manual assignment of the SNN is required if the following is true:
- One or more controller ports are on aCIP Safety™subnet that already has an established SNN.
- A safety project is copied to another hardware installation within the same routableCIP™Safety system.
IMPORTANT:
If you assign an SNN automatically or manually, make sure that system expansion does not result in a duplication of SNN and unique node reference combinations.
A warning appears if your project contains duplicate SNN and unique node reference combinations. You can still verify the project, but Rockwell Automation recommends that you resolve the duplicate combinations.
However, there can be safety devices on the routable safety network that have the same SNN and node address and are not in the project. In this case, these safety devices are unknown to the Logix Designer application, and you will not see a warning.
If two different devices have the same node references, the safety system cannot detect a packet received by one device that was intended for the other device.
If there are duplicate unique node references, as the system user, you are responsible for proving that an unsafe condition cannot result.
Follow these steps to change the controller SNNs to manual assignments.
- On the Online toolbar, click the Controller Properties icon.
- On the Controller Properties dialog box, click the Safety tab.
- On the Safety tab, click the ellipse button to the right of the safety network number for the port that you want to change.
- On the Safety Network Number dialog box, select Manual.
- Enter the SNN as a value from 1…9999 (decimal) and then click OK.
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