Modbus RTU communication routine between Delta Eh3 series PLC and thermostat

Delta EH3 series PLC With thermostat MODBUS RTU Communication routines

The thermostat used here is ： Delta's DTA4848V1 Type thermostat , As shown in the figure below ,

PLC Wiring with thermostat ：

Wiring diagram of thermostat , As shown in the figure below , among 9 Terminal No. is RS485-,10 Terminal No. is RS485+

The physical wiring diagram can be referred to as follows ：

Parameter setting of temperature controller ：

First , To set the type of temperature sensor and the temperature display unit , The following figure shows the contents of the thermostat manual ,

The type of temperature sensor can be described in the manual , as follows