How to use Arduino UNO as a Modbus Rs485 master

Projects General Guidance
1

I was struggling using the TX/RX pin which is the pin 1/0 in the Arduino to communicate with the Modbus. This is the Modbus Temperature and Humidity sensor that I used: https://anyingroup.en.alibaba.com/product/60383043566-801675809/Industrial_Digital_temperature_and_humidity_controller_A_TH1.html

Can anyone who has done a sample of Arduino - Modbus connection guide me?
How can I send a signal to the Modbus in order to get the value of the temperature and humidity. And how can I set the Modbus ID as I need to connect to some of it.

2

The Arduino pins operate at TTL logic levels, 3.3-5V.
RS485 operates at 7-12V.

You will need some kind of converter and may damage your Arduino if you connect RS485 directly to the pins

3

Not only that, but RS485 is a differential signal, not a single wire like RS232 (which can also swing to +/-10V to +/-25V levels).
You need an interface chip, see Figures 1,2,3:
https://datasheets.maximintegrated.com/en/ds/MAX1487-MAX491.pdf

4

Thank you for the response. I will check it out and tell you all if there is any problem.

5

have a look at
https://www.cooking-hacks.com/documentation/tutorials/modbus-module-shield-tutorial-for-arduino-raspberry-pi-intel-galileo/