Has some one R444A01 modbus rtu protocol

Question

I am looking for something like a datasheet for the R444A01 modbus rtu protocol. I want to implement a tool to read the temperature and the Humidity of this sensor.

the only thing what I could found is something like this: https://www.mikrocontroller.net/attachment/376848/datenBlatt_teil2.pdf

But to implement the tool I miss information about the modbus register definitions like Modbus address, which register stores which information and how many bytes are used.

May someone have some information about this sensor.

Answer 1

https://www.aliexpress.com/item/33054683552.html shows the R444A01 modbus RTU communication protocol. I could not find a proper datasheet either.

Answer 2

Quoting one of the reviewers from https://www.amazon.co.uk/Temperature-Humidity-humidity-temperature-External/dp/B078PHLR4T:

Supply voltage: DC 5-40V (recommended 6.5-28V) MODBUS RTU protocol, 03 read command, 06 write command. Serial port baud rate: 9600 (default), N, 8, 1

Temperature Register Address 0x0000 (2 bytes) Humidity Register Address 0x0001 (2 bytes) RS485 Address 0x0002 (2 bytes) Baud Rate 0x0003 (2 bytes)

Baud Rate Table : 0:1200 / 1:2400 / 2:4800 / 3:9600(default) / 4: 19200

Values returned in temperature is a SIGNED two byte value meaning that a 1 in the highest bit indicates a negative temperature. Divide by 10 (decimal) to get the actual value

Values returned in humidity is an UNSIGNED two byte value. Divide by 10 (decimal) to get the actual value