hexagon logo
Register Sign in
  • Replies 9 replies
  • Subscribers 221 subscribers
  • Views 544 views
  • Users 0 members are here
Options
Related

Looping question: Unique Input for Each Part plus Skipping Stations

Erikir
I'd like to write a program capable of inspecting 4 identical parts mounted to fixtures, pitched 100mm apart from one another.
The user will be asked where each part came from (location on on the CNC machine)
Each report pdf will be named to identify where each part came from.
It will be possible to skip one or several of the parts.

The program I have allows me to do all of this except for the looping. 

Manual alignment
Ask user part location
DCC alignment
Features
Dimensions
Report with pdf name identifying part location


Using the help file, I can create a simple looping program to measure the four parts, but I'm not sure how to include part identification and part skipping. I'd rather not have to have the program pause between parts while waiting for user input.
Parents
  • Step 0: don't use the PC-DMIS Loop & End Loop commands.
    They work great for simple jobs without variation, not for complex work.

    My #1 choice is a Do Until Loop.

    The Do Until Loop is a pair of commands, Do and Until, bracketing your inspection code with the "stop looping" condition being in the Until statement that's at the end of the loop.

    Step 1:
    There is no automatic loop # iteration tracking, you have to code that into the beginning of the loop.
    That's easy - before the loop declare a variable and set it's value to zero 
    ASSIGN/COUNTER=0

    Then the very first line after the Do command begins the loop is 
    ASSIGN/COUNTER=COUNTER+1


    Here's a sample of that structure: 
    ASSIGN/COUNTER=0
            DO/
            ASSIGN/COUNTER=COUNTER+1
$$ NO,
            "measure the part
            UNTIL/COUNTER==4

    So you see the code inside the Do -Until pair is going to get run 4 times.

    Step 2:
    There is no automatic alignment offsetting, you have to code that into the beginning of the loop.
    To handle this, I find a very effective method is to have a simple Generic Point with:
    a) fixed permanent zeros (0+0 formulas) in the Nom fields,
    b) variables on the Meas fields.
    Then a simple Origin Only alignment that sets the Generic Point as origin.
    But the real trick is that the Meas or actual values of the generic point come from some simple IF statements based on the COUNTER # of the loop corresponding to which fixture station. 


    ASSIGN/COUNTER=0
            DO/
            ASSIGN/COUNTER=COUNTER+1
            IF/COUNTER==1
              ASSIGN/FIXTURE_X=0
            END_IF/
            IF/COUNTER==1
              ASSIGN/FIXTURE_X=100
            END_IF/
            IF/COUNTER==1
              ASSIGN/FIXTURE_X=200
            END_IF/
            IF/COUNTER==1
              ASSIGN/FIXTURE_X=300
            END_IF/
LOOP_ORIGIN=GENERIC/POINT,DEPENDENT,CARTESIAN,$
            NOM/XYZ,<0+0,0+0,0+0>,$
            MEAS/XYZ,<FIXTURE_X,0+0,0+0>,$
            NOM/IJK,<0+0,0+0,1+0>,$
            MEAS/IJK,<0+0,0+0,1+0>

A1         =ALIGNMENT/START,RECALL:STARTUP,LIST=YES
              ALIGNMENT/TRANS,XAXIS,LOOP_ORIGIN
            ALIGNMENT/END
$$ NO,
            "measure the part
            UNTIL/COUNTER==4


    With this method, the nominals of the code inside the loop can NEVER be modified accidentally by PC-DMIS.

    Chew on that for a minute while I check on my students.


Reply
  • Step 0: don't use the PC-DMIS Loop & End Loop commands.
    They work great for simple jobs without variation, not for complex work.

    My #1 choice is a Do Until Loop.

    The Do Until Loop is a pair of commands, Do and Until, bracketing your inspection code with the "stop looping" condition being in the Until statement that's at the end of the loop.

    Step 1:
    There is no automatic loop # iteration tracking, you have to code that into the beginning of the loop.
    That's easy - before the loop declare a variable and set it's value to zero 
    ASSIGN/COUNTER=0

    Then the very first line after the Do command begins the loop is 
    ASSIGN/COUNTER=COUNTER+1


    Here's a sample of that structure: 
    ASSIGN/COUNTER=0
            DO/
            ASSIGN/COUNTER=COUNTER+1
$$ NO,
            "measure the part
            UNTIL/COUNTER==4

    So you see the code inside the Do -Until pair is going to get run 4 times.

    Step 2:
    There is no automatic alignment offsetting, you have to code that into the beginning of the loop.
    To handle this, I find a very effective method is to have a simple Generic Point with:
    a) fixed permanent zeros (0+0 formulas) in the Nom fields,
    b) variables on the Meas fields.
    Then a simple Origin Only alignment that sets the Generic Point as origin.
    But the real trick is that the Meas or actual values of the generic point come from some simple IF statements based on the COUNTER # of the loop corresponding to which fixture station. 


    ASSIGN/COUNTER=0
            DO/
            ASSIGN/COUNTER=COUNTER+1
            IF/COUNTER==1
              ASSIGN/FIXTURE_X=0
            END_IF/
            IF/COUNTER==1
              ASSIGN/FIXTURE_X=100
            END_IF/
            IF/COUNTER==1
              ASSIGN/FIXTURE_X=200
            END_IF/
            IF/COUNTER==1
              ASSIGN/FIXTURE_X=300
            END_IF/
LOOP_ORIGIN=GENERIC/POINT,DEPENDENT,CARTESIAN,$
            NOM/XYZ,<0+0,0+0,0+0>,$
            MEAS/XYZ,<FIXTURE_X,0+0,0+0>,$
            NOM/IJK,<0+0,0+0,1+0>,$
            MEAS/IJK,<0+0,0+0,1+0>

A1         =ALIGNMENT/START,RECALL:STARTUP,LIST=YES
              ALIGNMENT/TRANS,XAXIS,LOOP_ORIGIN
            ALIGNMENT/END
$$ NO,
            "measure the part
            UNTIL/COUNTER==4


    With this method, the nominals of the code inside the loop can NEVER be modified accidentally by PC-DMIS.

    Chew on that for a minute while I check on my students.


Children
No Data
© 2024 Hexagon AB and/or its subsidiaries. Privacy Policy | Cloud Services Agreement