Modbus connectivity issues


I am trying to connect three gas flow meters to my laptop through modbus. When I connect the first meter, it gives a 'Time out" error, also I am not able to communicate with the device, i.e. not sure how I command it to let gas flow through. The user manual with the device is useless since its in a different language and the manufacturer has not yet responded my request for an English version.

any guideline will be much appreciated.
Attn: 19120017

The first thing you need to establish is that the hardware communications link is setup correctly.
If this is from your Laptop, are you communicating via RS-232, RS-422 or RS-485....?

Once you have the correct hardware cabling configuration, you will need to have the correct Modbus slave address configured in both your Laptop and the Flow Meter.

Do you have these first 2 steps setup correctly...?