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AC800m RS-232 communication receive problem

Hallo,

i'm having problems receiving data via RS-232. I have connected my AC800M to my PC using RS-232 through COM 3 (there's an RS232 sniffer in between). I can write data on my PLC and the PC will receive it perfectly.

I can't receive data on my PLC from my PC (using Termite to send data), although my RS232 sniffer sees the data (so the data was send).

I'm using the standard SerialCommLib (2.3-1). 9600 baudrate, no parity, 8 bits, 1 stopbit, no flow control. Code i'm using:

(* Connect communication *)

IF NOT RS_232_Connect.Valid THEN
      RS_232_Connect( En_C := En_C, 
                Channel := Channel, 
                Valid => Valid, 
                Error => Error, 
                Status => Status, 
                Id := COM3_Ch_Id );
END_IF;

(* Setup communication *)

RS_232_Setup(  Id := COM3_Ch_Id,
               Req := Valid,
               ChSumType := 0,
               ChSumLength := 0,
               ChSumStart := 0,
               ChSumStop := 0,
               EnLineEditor := false,
               EnEchoChar := false,
               Done => Done,
               Error => Error,
               Status => Status,
               ParError => ParError );

(* Write communication *)

RS_232_Write(  Id := COM3_Ch_Id,
               Req := bSendMsg,
               EndChar := 13,
               Done => Done,
               Error => Error,
               Status => Status,
               Sd := RS232_MSG,
                              ParError => ParError );

(* Read communication *)

RS_232_Read( Id := COM3_Ch_Id, 
             Enable := bListenRS232, 
             MsgLength := 0, 
             EndChar := 13,
             NoOfTrailChar := 0, 
             Error => Error, 
             Status => Status, 
             Rd => IncomingMessage, 
             Ndr => Ndr,
                          ParError => ParError );