communication Profibus Rs485 with energy meter

I have a problem how to communicate my API S7 with a GQ12 Series Rail Mounting 3 Phase Energy Meter which use the RS485 s protocole. i have read the manuel GQ12 Sommy but I didn't understand anything. I want to know if it is possible to take all the data from him or not?

thank you in advance

Hello MedRamy;

Your reaction to the manual you posted indicates you are not familiar with Modbus, the information found in the document is quite clear for those of us who have worked with it.

First point, you should start by reading this excellent introduction to the Modbus protocol, provided by our friend smiffy. It has helped many members here over the years.

https://support.industry.siemens.com/tf//us/en/posts/modbus-general-description/66876/?page=0&pageSize=10

Next point, we need information on the controller you plan to use, and the software version you use to program it, if we are to help you further. This will allow us to describe the Modbus functionality of your controller, and of the communication functions you will need to program for Modbus RTU exchanges.

Finally, whatever the controller, you cannot use a Profibus port or CP to send data over raw RS-485. To communicate with a Modbus RTU (serial, RS-485) slave you will probably need a serial communication processor that can provide Modbus exchanges between the master and slave. When we understand the hardware/software of your controller we can provide more details.

Hope this helps,

Daniel Chartier 

yes i meant PLC, S7 1200 . i need to know how can i connect with it ( energy meter GQ12) and how could i bring a selected data from it ?

thank you in advance 

Hello MedRamy;

I hope you took the time to read smiffy's introduction to Modbus, as it will be useful to understand and follow the configuring and programming of Modbus RTU exchanges on a S7-1200 CPU, with a CM 1241 RS 485 communication module.

From the S71200 System manual the section on Modbus RTU:

https://support.industry.siemens.com/cs/mdm/109741593?c=86262523019&lc=en-WW

How do you establish a MODBUS-RTU communication with STEP 7 (TIA Portal) for the SIMATIC S7-1200?

https://support.industry.siemens.com/cs/us/en/view/47756141

How can you read input words in the address range from 9999 to 65535 with the SIMATIC S7-1200/S7-1500 via Modbus RTU?

https://support.industry.siemens.com/cs/us/en/view/109474481

The manual you showed us shows the parameters for requesting the phase voltage A from the GQ12, configured at slave address 1. Note that all addressing for the meter is done in hexadecimal notation, and the results seem to be hexadecimal also. By reading the registers as decimal the conversion will be made by the Step 7 program.

Hope this helps,

Daniel Chartier