modbus communication with arduino uno

Using Arduino Programming Questions
1

hi,
friends

i am trying to communication with modbus to arduino uno. i am working on this instrument(http://www.unitechinstrument.com/images/Support%20PDF/Manual/25%20UT-101-UNI.pdf) and i am trying to get data on arduino. But i am not getting any kind of data and i am attach serial monitor screen and code so help me

serial monitor display.png
serial monitor display.png1366×768 109 KB

_26y.ino (1.2 KB)

2 
  mySerial.write("req, sizeof(req)");

I doubt seriously that the device understands that string. What possessed you to put the quotes there?

    Serial.println(byte(RS485Byte), DEC);

Why are you finding it necessary to cast a byte to a byte?

3

thanks for reply pauls

i am finding code of modbus and combine it. i am try so many code but not get data on arduino. if any change in code you told me.you give me suggestion and help me. please

4

Did you remove the double quotes from that statement? If not, you are wasting my time.

5

thanks pauls.
but i am not getting any data.
i am not wasting any one time but i want to solution how to get data on arduino from modbus rs485. how to get data please help me please

6

any budy help me,
how to modbus data get on arduino uno?
i am trying so many time but don't get data on arduino.Any kind of suggestion and code you have so help me
please

7

how to defined modbus register address in arduino?
how to read and write data on register in arduino?