Hi
I'm a complete newbie , I'm having trouble setting up a chint dtsu666-ct talking via modbus to my node red . I'm connecting via a usb/485 . I've got a Heatmiser Edge HC thermostat that I can connect to and get all info I need but the Chint meter wont do anything !

 

You can try to use a Modbus scanner tool (e.g., QModMaster or similar) to see if you can read data from the Chint meter outside of Node-RED.

 

RS-485 communication issues are typically due to either incorrect wiring or incompatible communication settings.

Double-check your wiring. Make sure you are connecting 3 wires: +, -, and signal reference (i.e. ground, common, etc.). Also, if either of the equipment use "A" and "B" labeling for the signals, note that there is not a single accepted polarity used by all manufactures. Some manufacturers use "B" for the +, while others use "A".

For communication settings, make sure all devices are configured for the same baud rate, parity, and number of stop bits. Each Modbus slave device must have a unique address. So your Chint device must be configured for a different address than the Heatmiser device (assuming they are connected to the same RS-458 bus).