How do I create and describe M-Functions in TwinCAT 2 NC I PLC Control ST?

I decribed M-function in System Manager, but how can I proggram logic for it in ST? I know how to build\clear interpolation group, link axis, load nc program. For example, my nc file should be like this:

do smth
Turn on cooling (via M100)
do smth else
Turn off cooling (via M100 or M101)
etc.

I found in Plc Control TcNci.lib this function blocks, but don't understand how and when I should use it: ItpConfirmHsk, ItpGetHskMFunc, (it returns int num of mcommand in line as I unterstood) ItpConfirmHsk.

Pre defined m's like M30 and M02 is working fine, but I want to create own m-functions.

I tried FirstNciSample at Beckhoff docs, and it works fine for M30 and M02. Every time I tried to modify code (nState 60) it ended with errors. Should I re write case sequence if my m-functions will be not always at the end of file? How I should re write '60:' state for handling m-functions?

nState: UDINT;
fbBuildGrp: CfgBuildExt3DGroup;
fbLoadProg: ItpLoadProgEx;
fbStart: ItpStartStopEx;
fbConfirm: ItpConfirmHsk;
fbClearGrp: CfgReconfigGroup;
--
CASE nState OF
0: pre define states
10: build interpolation group
20: load part program
30: wait until interpreter is READY
40: start part program
50: check if interpreter is not READY
60:
    (* confirm m-func - e.g. m30 *)
    (* add code to handle m-functions *)
    (* in the moment all m-functions are directly confirmed *)
    IF ( ItpIsHskMFunc(in_stItpToPlc) ) THEN
        bConfirm    := TRUE;
    ELSE
        bConfirm    := FALSE;
    END_IF
    fbConfirm(
        bExecute:= bConfirm,
        sNciToPlc:= in_stItpToPlc,
        sPlcToNci:= out_stPlcToItp );
    IF NOT fbConfirm.bBusy THEN
        IF fbConfirm.bErr THEN
            (* an error occured *)
            (* this usually can just occur, if a confirmation is triggered without a request *)
            bErr        := TRUE;
            nErrId  := fbStart.nErrId;
            nLastState  := nState;
            nState  := 9999;
        END_IF
    END_IF
    nItpState   :=  ItpGetStateInterpreter( in_stItpToPlc );
    IF nItpState = NCI_INTERPRETER_READY THEN
        (* part program is finished without an error *)
        fbConfirm( bExecute:= FALSE, sNciToPlc:= in_stItpToPlc, sPlcToNci:= out_stPlcToItp );
        nState  := 70;
    ELSIF nItpState = NCI_INTERPRETER_ABORTED THEN
        (* a runtime error occured - e.g. a lag distance error occured *)
        bErr        := TRUE;
        nErrId  := ItpGetError(in_stItpToPlc);
        nLastState  := nState;
        nState  := 9999;
    END_IF
70: clear intrepolation group and switch nState to 0
9999: stop all and display an error
END_CASE

I have worked on NC I with Twincat3 once and I have created my own M-functions as well.

First, you have to define your M-function number and name to:

Channel => Interpreter => M functions

For example, I have set

M12 as LaserOn

M13 as LaserOff

. When I call M13(LaserOff) on NC File, I want to reset M12(LaserOn). So, you can see the Reset (3,6...) section on the table. I have put ,,12'' (which is number of M function) to LaserOff's Reset section.

In code side I have created property like ,,IsLaserOn, IsLaserOff, IsGasOn, IsGasOff''..

IsLaserOn := ItpIsFastMFunc ( nFastMFuncNo:= 12 , sNciToPlc:= sNciToPlc );
IsLaserOff := ItpIsFastMFunc ( nFastMFuncNo:= 13 , sNciToPlc:= sNciToPlc );

ItpIsFastMFunc is a function of tc2_nci library

In ST code side I use the M-functions like:

IF IsLaserOn THEN
    // your code to set laser on...
END_IF

IF IsLaserOff THEN
    // your code to set laser off...
END_IF

Note: You do not have to set set LaserOn to false when LaserOff is set on NC file. Because We have already reset the M12 function if M13 function is set on NC file.

This is the basic code to create and our own M-function and how to run in ST code. You can adjust and implement to your code.

Here is an example NC file code for test:

Good luck.