The Pilz PSS 3074 is a programmable safety controller with 48 discrete inputs (including 6 alarm inputs), 18 single‑pole and 8 dual‑pole outputs, LED status indicators, and a 24 VDC power supply. Common failure points for this class of safety PLCs include degraded input/output contact integrity, firmware corruption, and power supply voltage drops; the unit’s 4‑digit display will typically show error codes such as “E01” for I/O faults or “E02” for communication errors. First‑check diagnostics should verify that the 24 VDC supply is within spec, inspect all wiring for loose or corroded connections, and review the displayed fault code against the manual’s troubleshooting table. If no error code appears, perform a quick I/O loop test by cycling each input and output while observing LED indicators to confirm functional status.[oss-gpt-20b]