Troubleshooting: Device Offline

Diagnostic sequence

1. Confirm the device is powered and locally healthy.
2. Confirm the SEMS device type/profile is correct.
3. Confirm the transport is correct:
   • Modbus TCP vs
   • Modbus RTU / RS485
4. Verify the address:
   • IP and TCP port for network devices
   • slave ID for serial devices
5. Verify serial settings where applicable:
   • baud rate
   • parity
   • stop bits
6. Check for duplicate slave IDs on the same RS485 bus.
7. Confirm device-side Modbus access is enabled.
8. Retry polling and review the event history for repeated communication failures.

When to stop

If the physical layer or device-side protocol enablement is unknown, stop and verify the vendor-side configuration before changing higher-level SEMS settings again.