Westfalia Separator PLC 100/3 (C) Controller (part #31907324) is a 24 VDC industrial control unit used in separator and purifier systems; it features a VDE0160 relay output and runs firmware version 93.22. Common failure modes for this class include power‑supply degradation, relay contact wear, and internal PCB solder joint fatigue, often presenting as intermittent I/O signals or loss of communication with the host system. First‑check diagnostics: verify 24 VDC input voltage and continuity to the VDE0160 output; inspect all connectors and solder joints for corrosion or cracked pads; review any stored error logs or PLC status LEDs for fault codes indicating relay failure or power‑supply instability.[oss-gpt-20b]