Modbus Communication with Schneider MFM
I am trying to do a Multidrop communication with8Schneider Conzerv EM6436 MFM with RS485 to my 800Xa system, i have connected a RS485 to RS232 Converter also. I am getting the data in Modscan but in logic made by me i am able to connect with device but unable to get the register data. I have attached the pics for the reference. If anyone can suggest me any possible reason for getting the data, i will be greatful to him. Thanks in Advance.
Some my first ideas:
- do you have a working phisical connection (Rx and Tx LED's for COM port of the controller should BOTH flash frequently)
- You are trying to read an area, described in the manual for BLOCK reading only (Table 6-9) = 20 registers each with 2 reisters (float) - means that you have to read all the 40 variables at once. And you are reading only 10
- Try first with starting address %MW10#3912 and read 2 variables (registers). That is Current average (registers 3912 and 3913 for float) and is for individual reading
- Try also with starting address %MW912 - sometimes 3 is added for read function (03)
- Try also with %QW10#... instead of %MW#. Both are usable for read of words
- your variables A1, A2, A3... have to be declared as INT (integer) in the application
Read carefully page 58 from the manual of the meter
You have used the correct blocks as well as the connection. However you need to check the format in which you have to give the starting register address. If all parameters are available in series (eg. register 3401,3402,3403) then it is correct. If not you have to create separate MBTCPRead for each parameter.