No Communication?
- Verify RS232/RS485 wiring matches pinout
- Check baud rate, parity, stop bits
- Confirm correct port and driver selected
- Verify node or station address
- Ensure controller/device is powered and active
Connection Established but No Data?
- Verify correct device addressing format
- Confirm correct register or memory area
- Check protocol selection and configuration
- Ensure device supports H‑Link communications
Intermittent or Unstable Communication?
- Inspect cable and shielding
- Verify proper grounding
- Check for electrical noise sources
- Confirm stable power supply
Incorrect Data or Values?
- Verify correct register mapping
- Confirm data type (bit vs word)
- Check byte ordering or interpretation
- Validate scaling and engineering units
Read Works but Write Fails?
- Confirm register is writable
- Check device mode (run/monitor)
- Verify correct command format
- Ensure valid data values are being sent
Device Not Responding Correctly?
- Verify communication module configuration
- Restart communication interface
- Confirm correct protocol settings
- Test with alternate cable or port
© HMS Networks AB 2025