PP skips Move Instruction

grth46

Hello guys,

i'm still learning RAPID programming and I've now been at this point multiple times which I don't understand.

I'm currently writing a procedure where I want to Move the Robot to a specific Jointtarget. After that move instruction an IF instruction should check a condition and execute another process if fulfilled. The whole code is in a FOR loop, so after the IF instruction it should move to the next position and check again. In this case the IF condition checks if the TCPs current position after the move instruction matches a predefined position.


Mentioned RAPID Code:

PROC target_selection()

     FOR g FROM 1 TO 31 DO

          MoveAbsJ E{g},v800,fine,Tooldata_1\WObj:=WO_MIKO;

          checkpos := CRobT (\TaskRef:=T_ROB1Id \Tool:=Tooldata_1\WObj:=wobj0);

          IF checkpos <> D{h} THEN

                t_mes;

          ENDIF 

 
     ENDFOR

 ENDPROC

For some reason I cant explain the program pointer skips the move instruction at the beginning of the loop, jumps directly into the IF branch and executes the process without moving to the checkpoint first. 

I've already tried to force the program pointer to execute the move instruction first before continuing by using several Wait instructions like WaitTime, WaitRob \InPos and \ZeroSpeed or StopMove and StartMove. Unfortunately I didn't find the reason for this yet. Maybe someone knows a solution for this.

grth46

I think I know whats going on.
For context: I started working with RobotStudio and RAPID four weeks ago and I haven't had any experience with robot programming so far. Along learning all of the features and instructions I was working on building a station of a real room with our ABB robot. First I created some targets and paths on the RobotWare Version 6.x and a few days ago I had to create a new virtual controller with RobotWare 7.x to include a force control feature i wanted to test. I tried to move all my workobjects, tooldata, targets and paths into the new controller which didn't work really well. Some features duplicated, some couldn't get moved, I don't know if there would have been a better way for this. After moving all of the most important features to the new controller I deleted the old controller and I think there is still some old information stuck somewhere in the project, which now interferes with some changes I'm doing to my RAPID Module. So I think the project may be corrupted in a way, otherwise I can't explain this strange behavior.

graemepaulin

Do you get any error messages?
If you step through the routine (using the step forward button) to execute one line of code at a time what happens?

grth46

I don't get any error messages. When cycling through the code step by step the robot doesn't do anything when executing the move instruction.
However it appears when I change the IF argument as seen below to check if the counter g of the array E has a specific value, the move instruction gets executed as intended.

IF g=2 OR g=5 OR g=7 OR ...
     t_mes;
ENDIF

The problem with this is that I want to set up this IF branch to be as compact as possible for large list of condition arguments (up to 160 entries) and on the other hand to make the whole code compatible to convert into other projects.

graemepaulin

Try declaring the FOR variable (g) as a num at the top of your module, for example PERS num g:=0;
Using the locally declared variable from the FOR statement should work but I have had issues in the past with using it later within the for loop.
You can then also easily see the value of the variable when stepping through the code as it will update the value in the declaration.

SomeTekk

The following may be of little value, as I succumbed to TL;DR for a lot of this chain.

The first argument in the MoveAbsJ instruction is a jointtarget data type. 

It seems to me that E{g} is a reference to an array element. In the past, difficulties with positioning data  in arrays have led to some exotic coding solutions, e.g. (No data declarations included) 

FOR arraynum to A_VALUE DO
GetDataVal jStringTargetNames{arraynum}\TaskRef:=T_YourDataHere, jposTemp1; 
MoveAbsJ,  posTemp1,speed, zone, etc...;

Of course I may have completely misdiagnosed the actual problem.

grth46

graemepaulin said:

Try declaring the FOR variable (g) as a num at the top of your module, for example PERS num g:=0;
Using the locally declared variable from the FOR statement should work but I have had issues in the past with using it later within the for loop.
You can then also easily see the value of the variable when stepping through the code as it will update the value in the declaration.

I've already done that. To avoid any conflicts at that step I've made sure to declare all of my targets, workobjects, tooldata, arrays and variables at the top of my module. I think it likely is a synchronisation problem, as I created most of these features in an old virtual controller and then probably failed to convert these informations correctly. I generally do a lot of research and try to solve any kind of problem by my own before I post a new thread, but in this case I think the fastest way to find out is just to recreate the current state in a new file and try again.

Fritz

Hi !

I do not understand your targets here, but I can see 2 issues in your code example above:

1. If you want some instruction to be executed only if move has been completely finished - you MUST ALWAYS put instruction WaitRob \InPos; between them. Otherwise program pointer is going ahead of motion pointer immediately.

2. You can not compare position variables for exact match if one of them is read by current position instruction CRobT(); - robot will never go nor stay on absolutely precise position. You can only compare some coordinate values to be in defined range.

Fritz