[?]: S7-300 Modbus problem with controller from Carel

[redmadhat]

There is a controller from Carel for management AHU.
Also there is S7-300 with CP for communications with Carel.
Data are stored in DB, in first half data for reading, and the second for record.
The information which comes from Carel correct (temperatures and setpoints coincide).
The problem consists when I wish to send the data on the controller from Carel (basically setpoints or a command of start of system)!
As soon as I enter into a mode monitoring (glasses) and I change value any and, step7 there is a mode a monitoring and blocks it.
Again to come into a monitoring mode, I should close window DB and again it open.
Why so occurs?