Variable size array

3 posts in this topic

Hello , It's been a long time since I last wrote here :-).

Now I'm using NJ 501-1300:-2

I would like to know if is it possible to have an array with a variable size and how to use it. Better I explain my problem so maybe you can suggest me a good way. I have several cam tables that I have to use depending on the format required , my idea is to have just a MC_CamIn   function and , depending format required, change the cam table. Es.    VAR_CamTableInFun (the variable that i want to use in the   MC_CamIn    function)   CAM_Data1 (ARRAY[0..2500] of _sMC_CAM_REF)  , CAM_Data2 (ARRAY[0..8500] of _sMC_CAM_REF), CAM_Data3 (ARRAY[0..800] of _sMC_CAM_REF) 

PAR_CamAxDivSrtMod          :=_mcAbsolutePosition;
VAR_CamAxDivSrtPos           :=LREAL#0.0;
VAR_CamAxDivMstSrtDis     :=LREAL#0.0;
VAR_CamAxDivMstScl          :=LREAL#0.0;
VAR_CamAxDivSlvScl            :=LREAL#0.0;
VAR_CamAxDivMstOfst        :=LREAL#0.0;
VAR_CamAxDivSlvOfst          :=LREAL#0.0;
PAR_CamAxDivRefTyp          :=_mcFeedback;
PAR_CamAxDivDir                  :=_mcPositiveDirection;
PAR_CamAxDivBufMod        :=_mcAborting;

                Master                              :=AxRac,
                Slave                                 :=AxDiv,
                CamTable                        :=VAR_CamTableInFun,        
                Execute                            :=CMD_AxDivCamIN
                Periodic                           :=True,                                                                                                                
                StartMode                       :=PAR_CamAxDivSrtMod,
                 StartPosition                 :=VAR_CamAxDivSrtPos,
                MasterStartDistance    :=VAR_CamAxDivMstSrtDis,
                MasterScaling                :=VAR_CamAxDivMstScl,
                 SlaveScaling                  :=VAR_CamAxDivSlvScl,
                 MasterOffset                 :=VAR_CamAxDivMstOfst,
                 SlaveOffset                    :=VAR_CamAxDivSlvOfst,
                 ReferenceType              :=PAR_CamAxDivRefTyp,
                 Direction                         :=PAR_CamAxDivDir,
                 BufferMode                    :=PAR_CamAxDivBufMod
                VAR_AxDivCamIN_InCam             :=Y_CamIN_1.InCam;
                VAR_AxDivCamIN_InSync             :=Y_CamIN_1.InSync;
                VAR_AxDivCamIN_EndOfProf      :=Y_CamIN_1.EndOfProfile;
                VAR_AxDivCamIN_Indx                 :=Y_CamIN_1.Index;
                VAR_AxDivCamIN_Busy                :=Y_CamIN_1.Busy;
                VAR_AxDivCamIN_Active              :=Y_CamIN_1.Active;
                VAR_AxDivCamIN_CmdAb            :=Y_CamIN_1.CommandAborted;
                VAR_AxDivCamIN_Err                    :=Y_CamIN_1.Error;
                VAR_AxDivCamIN_ErrID                :=Y_CamIN_1.ErrorID;

If Format=1 then

    VAR_CamTableInFun := CAM_Data1  ;

elsif Format=2 then

   VAR_CamTableInFun := CAM_Data2  ;

elsif Format=3 then

  VAR_CamTableInFun := CAM_Data3  ;


So you think is it possible? Of course VAR_CamTableInFun  must be an array with variable size, otherwise error size data do not match.

Best regards






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On it's very core, NJ is still a PLC, so unfortunately such dynamic memory management function is not implemented.

IMO if you just have 3 Cam tables, it is way easier to create 3 MC_CamIn instructions and one MC_CamOut. Ensuring the Cam transition is easier by having multiple FBs. In the end if you want to only have one FB, you need to make each Cam Table to be in the same master-slave scale, so the array size of those 3 will be the same.

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We now have variable size arrays, but you must use them as input or output to a user-defined function block.

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