I am trying to send commands to a heater that has a RS232 communication module, and like my college before of me I also get the 7000 error message from the Send_PTP block. But I'm not shure that this error is even present because the error bit of the same block is not active.

Also it's strange that no LED are flashing on the CM1241 module. Is there a way to check if the communication is even working?

I've just noticed in the documentation of the heater that the pinout of the DB9 connector is not the same as the pinout of the CM1241. Maybe this is the problem. The diference is that pin 4 is not defined in the heater, but it is in the CM1241(DTR).

Pinout of the heater:

Pin 2 RxD Receive Data

Pin 3 TxD Transmit Data

Pin 5 0 V Signal GND

Pin 6 DTR Data terminal ready

Pin 7 RTS Request to send

Pin 8 CTS Clear to send

Do I connect the same pins of the heater to the pins of the CM1241?

Best regards.

Ales