Cause : Peer to peer and master-follower communication loss comes when communication between devices has been disrupted. This issue can affect systems that rely on synchronized control, where devices are set up as either peers (equal status) or in a hierarchical master-follower relationship.

A112 alarm in ABB DCS800 drive indicates Peer to peer and master-follower communication loss. This means a loss of communication between the drive and the followers.

1. Check all network cables and connectors for secure connections. Look for loose, worn, or damaged cables, which could disrupt signal transmission.
2. Confirm that each device has a unique address on the network and that the master device correctly recognizes each follower. Address conflicts are a common cause of communication issues.
3. Power down the entire system, including all connected devices. Wait a few minutes, then restart each device in the correct order (master first, followed by followers). This can reset communication between devices.