M91-t4-r6-zk1 Manual -

| Symptom | Likely cause | Solution | |---------|--------------|----------| | No PWR LED | Input voltage missing | Check fuse/power supply | | ERR LED on | Thermocouple open circuit | Check wiring on t4 inputs | | No Modbus response | Wrong slave ID or baud rate | Verify zk1 DIP switches | | Relay chattering | Inductive load back-EMC | Add snubber diode across load |

| Output Type | Qty | Max Load (Resistive) | Max Load (Inductive) | Protection | |-------------|-----|---------------------|----------------------|-------------| | Relay (r6) | 6 | [e.g., 5A @ 250V AC]| [e.g., 2A] | None (external varistor) | | Transistor (t4) | 4 | [e.g., 0.5A @ 24V DC]| [e.g., 0.2A] | Short-circuit / overtemp | M91-t4-r6-zk1 Manual

Perform the initial startup sequence and calibration procedure, verifying that the unit responds accurately to control inputs. Maintenance Guidelines | Symptom | Likely cause | Solution |