No sent frames; quality is Uncertain and the update count does not change
First check whether the connection has actually been established.
- Serial driver: confirm that the port exists and is not in use by another application.
- Network driver: check that the TCP server is running and that the target IP address and port are correct. Check network reachability first if useful; a successful Ping alone does not prove that the TCP port is available.
Request frames are sent, but no response returns
Check the driver type and communication settings first.
- Serial driver: check the serial cable, wiring and device ID.
- Network driver: check the device ID and target communication settings.
Quality alternates between Good and Bad
Inspect sent and received frames to see whether some requests receive no response. The source suggests increasing the device’s request-frame interval, with 500 milliseconds as an example to try. That is a troubleshooting example from the source, not the default for every driver, model or site. Verify the setting against device response behavior and the project’s update requirements.
Some points are Good and others are Bad
Check whether only particular point configurations are affected.
- Confirm that the device supports the register types used by the Bad points.
- Check the addresses and ranges against the device point list.
- If frame analysis is available, use returned error frames to review the point configuration and interpret errors using the device protocol document.
Verification after each change
Change one condition at a time, then observe sent frames, responses, update behavior and quality. Confirm that representative points remain stable and correct before adding more points.