Error recovery by finishing the loop

    Hello.

    I have a program which welds, trims and stacks the product all in one loop. Recovering by backtracking is due to complexity not an option,

    I would like to create "recovery program" which is a simplified copy of the production loop, minus the production steps, DO's, Di's etc.. Basically, "recovery program" should start where production loop had stopped and end up back at home like it normally would.

    For that, in recovery program, i need to jump in it at correct line based on current (approximate) robot position. But how to accomplish that? Using DCS zones is not an option for me.

    Thanks in advance.

    • Best Answer

    Good morning,

    you could add a GO[]=... to the movements to store a number (of your choice) related to the position. Like ...

    Code
    J PR[1:home] 100% FINE GO[1]=1
...
J PR[10:pre] 100% FINE GO[1]=10
J PR[11:weld] 100% FINE GO[1]=11
J PR[12:post] 100% FINE GO[1]=12

    You can determine the last reached position by just reading the value in GO[1] and use it to move forwards or backwards to HOME.

    Maybe Distance Before, Time before|after and/or some kind Point logic can fit your needs also. Depends on the way the program is written. You may have a look to the Additional Motion Instructions in the Basic Operation Manual for details. :winking_face:

    Addition:

    You also can use the last known position as a target for an (indirect) jump:

    Kind regards

    Jörn

    Edited once, last by HalbesYoyo (September 5, 2023 at 9:09 AM).

    Either way has it advantages and disadvantages.

    Advantage of using a GO is that the robot will set the GO as soon as the position has been reached. A disadvantage is, that only one Additional Motion Instructions for a motion command can be used at a time. If you need to use one of the other Additional Motion Instructions you can't use the GOs and you will have to set a register separately.

    First of all you should set the register after the motion:

    Code
    J PR[11:weld] 100% FINE
  R[1]=11

    This way the register will only be set if the position actually has been reached. The disadvantage of separating setting a register and the motion is, that if the program will be stopped right between the motion and setting the register the actual position and the content of the register do not match.

    Anyway. Both ways only tell you the last position the robot has actually reached. Thus if the program stops while the robot is in motion you only know it is somewhere between this last reached and the next position.

    Also keep in mind that an operator may has jogged the robot manually. But you can use the system variable $MOR_GRP[1].$JOGGED to check this. :winking_face:

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