Taidacent SHT30 RS485 Modbus RTU Temperature and Humidity Sensor Transmitter for PLC and DCS Room Thermocouple Monitoring

Excellent for price. n = no parity. My PLC only allows 400001 as starting address, where the instructions said 40001. However, when I entered 400001 it did not matter, it gave me the results. Don't forget to divide the numbers by 100 to get the correct temperature and % humidity. Convert from Deg C to Deg F by multiplying by 1.8 and adding 32. I also forgot to hook up the red wire. It works fine with 24 VDC.

Excellent product. Very accurate. Only reason that I did not give it 5 stars is that I could not set the baud rate. The documentation about baud rates has errors. Address 66 and 67 are referenced as baud rate. The write register example reads the register. If 9600 baud is fast enough, this product works fine.

It connected right up to my USB-to-RS485 interface, and my PC could read it right away using python's pymodbus module. Value agrees with other temperature sensors.

Works fine, you just have to poll function code 03 (holding registers) and the transducer I received had slave address 01. Temperature is located at register 1 (address 0) and humidity is register 2 (address 1). IMPORTANT I found that if you poll more than 2 registers in one message, the transducer seems to go into an 'auto broadcast' mode, where it automatically transmitts on a 1-2 second interval. This gave me a bit of a headache.

Got this working by powering red wire with 24vdc, green ground. Baud rate 9600, 8 data bits, parity none, 1 stop bit, slave node # 1.