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+--- Thread: KC 868-A16 RS485 (/showthread.php?tid=8486)
KC 868-A16 RS485 - daudrimu - 09-03-2025
Hello,
I am trying to connect a pressure sensor to my KC868-A16 board using RS485 communication. The sensor works via Modbus RTU, and I want the KC868-A16 to act as the master.
Here are the issues I am facing:
- On the web configuration page of KC868, I can see General Protocol and Custom Protocol, but I am not sure which one I should use for the pressure sensor, since it is not listed in the default devices.
- I have tested the RS485 line with a USB-RS485 adapter and Modbus Poll, and I can see the sensor replying with values (e.g. 500, 0, 500, …). So the sensor is working correctly.
- When I try to scan for slave IDs from Python via the KC RS485, I only get timeout errors. TX is active, but RX never receives data.
- I have already checked the wiring (A↔A, B↔B, and GND connected), baudrate, parity, stopbits, and slave ID, but still no communication between KC and the pressure sensor.
- How should I configure KC868 in the web interface to read registers from the pressure sensor?
- Do I need to use General Protocol or Custom Protocol?
- Is there any example of how to set the registers mapping for an external Modbus RTU sensor?
RE: KC 868-A16 RS485 - admin - 09-03-2025
KCS firmware not use for customize RS485 sensor.
if you want use for home assistant, i suggest you config by ESPHome via modbus controller. You can also write your own Arduino code for your project.