May 26, 2019, 09:27:46 PM
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 PR been changed from Cartesian to Joint

normal_post Author Topic:  PR been changed from Cartesian to Joint  (Read 357 times)

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March 15, 2019, 06:24:30 AM
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Hello Guys,
I've been working on a R-2000iC/125L with pretty standard software package (handling tool/DCS).
There's a taught position with PR[1] as tool offset to slightly adjust this taught position.
And this robot was running for almost a week without program, been through that taught position thousands time.
But one day, robot just went to middle of nowhere and hit axis limit and I found that PR[1] was changed from Cartesian to joint format, and also the numbers in PR[1] were completely different then before.
And I'm positive that I'm the only person who can change coordination via teach pendant, and there's no such command like PR[1]=JPOS in my program.
Just want to ask, is there any setup/routine/ that could overwrite numbers and coordination in position register?

Today at 09:27:46 PM
Reply #1



March 15, 2019, 10:17:30 AM
Reply #1


I know exactly from first hand experience what causes this. It took my years to figure this out.

There is a karel program called Get_Home that if someone runs this program it causes PR1 to change to Joint.

Best solution I found was to disable the karel programs with the variable so there are not seen in the program list.

Another solution is to just not use PR1. I have done this before just to be extra safe.

March 15, 2019, 12:16:04 PM
Reply #2


That is incredibly helpful. One of our machines requires a Karel program to connect to a computer system, so we often leave the Select list filtered to Karel programs. One day it was stopped in cycle and our techs tried to get back to home and had no idea that they needed to re-filter to TP programs and ran Get_Home instead. They were very confused when it said it was running but did not move the robot to home or bring up the normal Edit screen. It is good to know what that program does!

March 16, 2019, 06:12:42 AM
Reply #3


Thanks a lot for the explanation!

March 17, 2019, 06:13:53 PM
Reply #4


Global Moderator
Get_Home does more than just change PR[1] to joint, it copies the values stored in refpos one and then throws those into PR[1] as a joint representation. In the auto industry, most of the big players use PR[1] as their home position.
Check out the position converter I wrote here!

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