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

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Dear all

I'm a new in S7 1200. I have

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!