Programming in ST Language

The example is programmed in ST structured litteral language. The dedicated section is under the same master task (MAST).

(* Function to write %MW100 to %MW140 in slave Y *)

(* --------------------------------------------- *)

CASE Step_4 OF

  0:

        (* Initialization *)

    IF (Start_4) THEN (* trigger flag *)

        Error_4 := 0;

        Step_4 := 5; (* next step *)

    END_IF;

  5:

        (* Send command to switch serial port from Modbus to character mode *)

    READ_STS(Ioddt_Pcmcia_0_3_1); (* read serial port status *)

    IF (Ioddt_Pcmcia_0_3_1.EXCH_STS = 0) THEN (* no active command *)

        Ioddt_Pcmcia_0_3_1.CONTROL := 16#00; (* reset control word *)

        SET(Ioddt_Pcmcia_0_3_1.MB_TO_CHAR); (* set MB_TO_CHAR command bit *)

        WRITE_CMD (Ioddt_Pcmcia_0_3_1); (* send command *)

        i := 0; (* initialize retry counter *)

        Step_4 := 10; (* next step *)

    END_IF;

 10:

        (* Test result of switch command *)

    READ_STS(Ioddt_Pcmcia_0_3_1); (* read serial port status *)

    IF (Ioddt_Pcmcia_0_3_1.EXCH_STS = 0) THEN (* command completed *)

        RESET(Ioddt_Pcmcia_0_3_1.MB_TO_CHAR); (* reset MB_TO_CHAR command bit *)

        IF (Ioddt_Pcmcia_0_3_1.EXCH_RPT = 0) THEN (* no error *)

            IF (AND(Ioddt_Pcmcia_0_3_1.PROTOCOL, 16#0F) = 03) THEN (* character mode OK *)

                Step_4 := 15; (* next step *)

            ELSE

                i := i + 1;

                IF (i > 1000) THEN

                    Error_4 := -1; (* error *)

                    Step_4 := 65; (* next step = end *)

                END_IF;

            END_IF;

        ELSE (* error in sending command to port *)

            Error_4 := -2; (* error *)

            Step_4 := 65; (* next step = end *)

        END_IF;

    END_IF;

 15:

        (* Send dial command to modem *)

    Adr_4 := ADDR('0.3.1.SYS'); (* communication port *)

    MngtPrint_4[3] := 50; (* timeout *)

    MngtPrint_4[4] := 16; (* number of bytes to send *)

    ReqString_4 := 'ATDT0102030405$N'; (* dial message *)

    PRINT_CHAR(Adr_4, ReqString_4, MngtPrint_4);

    MngtInput_4[3] := 300; (* timeout *)

    MngtInput_4[4] := 0; (* number of bytes to send *)

    INPUT_CHAR(Adr_4, 0, 12, MngtInput_4, AnsString_4); (* wait modem reply *)

    Step_4 := 20; (* next step *)

 20:

        (* Test PRINT_CHAR function result *)

    IF (NOT MngtPrint_4[1].1) THEN

        IF (MngtPrint_4[2] = 0) THEN

	          Step_4 := 25; (* success : next step *)

        ELSE

	          Error_4 := -3; (* error *)

           Step_4 := 65; (* next step = end *)

        END_IF;

    END_IF;

 25:

    (* Test INPUT_CHAR function result *)

    IF (NOT MngtInput_4[1].1) THEN

        IF (MngtInput_4[2] = 0) THEN

	          Step_4 := 30; (* success : next step *)

        ELSE

	           Error_4 := -4; (* error *)

            Step_4 := 65; (* next step = end *)

        END_IF;

    END_IF;

 30:

    (* Test Modem reply *)

    IF (AnsString_4 = 'CONNECT 9600') THEN

	       Step_4 := 35; (* success : next step *)

    ELSE

	       Error_4 := -5; (* error *)

        Step_4 := 65; (* next step = end *)

    END_IF;

 35:

    (* Initialize OUT_IN_MBUS parameters *)

    MbusCmd_4[1] := 10; (* slave PLC address *)

    MbusCmd_4[2] := 16#06; (* Modbus function 16#06 *)

    MbusCmd_4[3] := 100; (* slave PLC area = %MW100 *)

    MbusCmd_4[4] := 41; (* quantity of data *)

    RetryLmt_4 := 2; (* number of retry *)

    DataBits_4 := %KW0.3.1.1.8; (* 1 = 8 bits -> RTU mode, 0 = 7 bits -> ASCII mode *)

    RespTout_4 := 300; (* timeout = 30s *)

    Flag_Error_4 := 0;

    Step_4 := 40; (* next step *)

 40:

    (* Call OUT_IN_MBUS *)

    Out_In_Mbus_4 (Adr_4, MbusCmd_4, RetryLmt_4, DataBits_4, RespTout_4, Abort_4,

                   %MW100:41, Retry_4, Active_4, Done_4, Flag_Error_4, Status_4);

    IF (NOT Active_4) THEN (* request completed *)

        IF (NOT Flag_Error_4) THEN (* no error *)

            Step_4 := 45; (* next step *)

        ELSE (* error *)

            Error_4 := -6; (* error *)

            Step_4 := 45; (* next step *)

        END_IF;

    END_IF;

 45:

    (* Hangup modem *)

    MngtPrint_4[3] := 50; (* timeout *)

    MngtPrint_4[4] := 9; (* number of bytes to send *)

    ReqString_4 := '+++ATH0$N'; (* hangup message *)

    PRINT_CHAR(Adr_4, ReqString_4, MngtPrint_4);

    Step_4 := 50; (* next step *)

 50:

    (* Test PRINT_CHAR function result *)

    IF (NOT MngtPrint_4[1].1) THEN

        IF (MngtPrint_4[2] = 0) THEN

	          (* Success : next step *)

	          Step_4 := 55;

        ELSE

	          (* End on error *)

	          Error_4 := 1;

           Step_4 := 65;

        END_IF;

    END_IF;

 55:

    (* Send command to switch serial port from Modbus to character mode *)

    READ_STS(Ioddt_Pcmcia_0_3_1); (* read serial port status *)

    IF (Ioddt_Pcmcia_0_3_1.EXCH_STS = 0) THEN (* no active command *)

        Ioddt_Pcmcia_0_3_1.CONTROL := 16#00; (* reset control word *)

        SET(Ioddt_Pcmcia_0_3_1.CHAR_TO_MB); (* set MB_TO_CHAR command bit *)

        WRITE_CMD (Ioddt_Pcmcia_0_3_1); (* send command *)

        i := 0; (* initialize retry counter *)

        Step_4 := 60; (* next step *)

    END_IF;

 60:

    (* Test result of switch command *)

    READ_STS(Ioddt_Pcmcia_0_3_1); (* read serial port status *)

    IF (Ioddt_Pcmcia_0_3_1.EXCH_STS = 0) THEN (* command completed *)

        RESET(Ioddt_Pcmcia_0_3_1.CHAR_TO_MB); (* reset CHAR_TO_MB command bit *)

        IF (Ioddt_Pcmcia_0_3_1.EXCH_RPT = 0) THEN (* no error *)

            IF (AND(Ioddt_Pcmcia_0_3_1.PROTOCOL, 16#0F) = 07) THEN (* Modbus mode OK *)

                Step_4 := 65; (* next step *)

            ELSE

                i := i + 1;

                IF (i > 1000) THEN

                    Error_4 := 2; (* error *)

                    Step_4 := 65; (* next step *)

                END_IF;

            END_IF;

        ELSE (* error in sending command to port *)

            Error_4 := 3; (* error *)

            Step_4 := 65; (* next step *)

        END_IF;

    END_IF;

 65:

    (* End *)

    Start_4 := 0; (* allow new demand *)

    Step_4 := 0; (* goto waiting state *)

END_CASE;