Trouble with communication between S1200 and a temperature controller

Hi guys, I'm a beginner in the PLC world and i would like some advices because i'm stuck in my program with the temperature controller.

I work on TIA portal V13, CPU 1217C DC/DC/DC, i have a CM 1241 RS485 module and the temperature controller is a DTE-10-T from DELTA.

I have tried the function block MB_COMM_LOAD with MB_MASTER to write/read data on the controller but when i try to read something it always fail and when i write something the led of the controller is flashing i guess the link is working but maybe i miss some parameters or character in the variable i use to read data.
The string i send to read max value is ':010310100002' and it does nothing :/
but when i try to write with ':010610100300' to put 300 ° on max value the led of the controller flash a little bit

Here is the doc of the temperature controller : https://www.automation.siemens.com/...ttachment.aspx?attachmentID=49595&Language=en

in MB_COMM_LOAD i have set : 2400 baud rate, parity none, 7 bits ..

if someone have an idea i'll be grateful

Are you using Modbus Ascii or Modbus RTU? I see that the Delta controller has both but S7-1200 I think (I cannot check at the moment) does only Modbus RTU. If so, then you dont send strings but use read and write of registers.
Did you use prper terminations, cabling and connectors?

i guess the connectors are ok because until now when i was trying to send strings and the block function give me the done variable at true and the module is flashing with MB_COMM_LOAD.(its not me who do the electrical part or the machine including the wiring and my collegue is on vacation i will check the wiring this morning)

if you say that the s1200 use only RTU i will try to use RCV_PTP and SEND_PTP instead of MB COMM

CM1241 Rs485

Greeting,

Please see attached both LED's Rx Tx flashing on 1Hz but nothing receiving at DATA_PTR output.

We are using Profibus connector at CM1241 port for termination resistance and R=120ohm at Modbus slve terminal.

Regard's