Read more than one float data via Modbus RTU using S7-1200 with CM1241

Dear all
I want to make S7-1200 as Modbus RTU gateway (Master and slave all in one)
I have bought :
1 x 1214C CPU
2 x CM1241 RS422/485
The fisrt S7-1200 act as Modbus RTU master to read float data from Modbus RTU salve (i'm using Modbus poll to act as slave). In Master block i try to read one float from slave and save to MD50->everything is ok.
http://i.imgur.com/hB4eG8M.jpg
But when I want to read more float data from a salve and save to DB. I only received 0 value althought i change value from salve
http://i.imgur.com/R9JZeGX.jpg
Please help me resolve this problem
Best regards!

Hi,

From this link:

https://support.industry.siemens.com/cs/document/47756141/how-do-you-establish-a-modbus-rtu-communication-with-step-7-(tia-portal)-for-the-simatic-s7-1200?dti=0&lc=en-WW

The DATA_PTR parameter (in your case, DB3) must refer to a global data block created with the disabled option "Symbolic access only".

Regards.

sigmadelta said:

Hi,

From this link:

https://support.industry.siemens.com/cs/document/47756141/how-do-you-establish-a-modbus-rtu-communication-with-step-7-(tia-portal)-for-the-simatic-s7-1200?dti=0&lc=en-WW

The DATA_PTR parameter (in your case, DB3) must refer to a global data block created with the disabled option "Symbolic access only".

Regards.

Click to expand...

Thank you. I have got it