Safety I/O Replacement Options
Two options for safety I/O device replacement are available on the Safety tab of the Controller Properties dialog box in the Logix Designer application:
- Only Allow Automatic Configuration When No Safety Signature ExistsSelect this option if you rely on a portion of the CIP Safety system to maintain SIL 2 or SIL 3 behavior during device replacement and functional testing.
- Always Allow Automatic ConfigurationSelect this option if you do not rely on the entire routable CIP Safety system to maintain SIL 2 or SIL 3 behavior during device replacement and functional testing.
For more considerations about choosing an automatic configuration setting, including example use cases, see the GuardLogix 5580 and Compact GuardLogix 5380 Safety Reference Manual, publication 1756-RM012.
Safety I/O Replacement Options
Only Allow Automatic Configuration When No Safety Signature Exists
When a safety I/O device is replaced, the configuration is downloaded from the safety controller if the DeviceID of the new device matches the original. The DeviceID is a combination of the node/IP address and the Safety Network Number (SNN) and is updated whenever the SNN is set.
If you select the Only Allow Automatic Configuration When No Safety Signature Exists option, follow the guidance in the following table to replace a safety I/O device based on your scenario. After you complete the steps, the DeviceID matches the original and enables the safety controller to download the proper device configuration and re-establish the safety connection.
Safety Signature Exists | Replacement Device Condition | Action Required |
|---|---|---|
No | No SNN (out-of-box) | None. The device is ready for use. |
Yes or No | Same SNN as original safety task configuration | None. The device is ready for use. |
Yes | Different SNN from original safety task configuration | |
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