We have a large library of weld programs for large programs that have 2-3 hour run times.
Since we are a high mix low volume facility, we have more programs than the teach pendant can retain. To work around this we move programs onto USBs back and forth from the pendant whenever required.
Sometimes when we transfer the program back into the pendant from the USB, the positioner/skyhook positional values associated with the weld lines only become affected. For example the original set point may be -41.55. After transferring to and from the USB, this value is now 41.55 +/-.
This has happened a few times now over a year.
Any suggestions on how to counter measure or any idea why this may be happening?