kmonroe023 Posted October 25, 2011 Share Posted October 25, 2011 We are utilizing the cross-coupled gantry algorithm for one of our machines running the Power Pmac. We hare having a sporadic problem I would like your opinion on. Occasionally, when the gantry is holding position the two gantry motors appear to start fighting each other. I've observed that the I2t sum on one of the motors will gradually accumulate to the point were it exceeds the limit, causing an I2t fault on that motor. When that happens the motor will disable, but then the gantry will run away making a howling sound (sorry for the low tech description, but I don't know how to describe it any other way). Disabling, then re-enabling both motors generally gets things back to normal and the machine will run fine for a significant period of time (several days) without problems. There does not seem to be any identifiable precursors to the motor problem, it seems to 'just happen'. The gantry structure itself is very rigid so I don't believe that is the cause. Any ideas as to what could be causing this? I thought I might have a problem with the way the motors are homed, but it runs normally the vast majority of the time so I basically ruled that out. Thanks, Kevin Monroe Link to comment Share on other sites More sharing options...
Omron Forums Support Posted October 25, 2011 Share Posted October 25, 2011 Could you possibly post screenshots of performing step moves and parabolic moves on your motors using the Tuning program? Link to comment Share on other sites More sharing options...
kmonroe023 Posted October 25, 2011 Author Share Posted October 25, 2011 Sure. The machine is currently running production, but we've got some time on it this Friday. I'll try to get some screen shots then. Link to comment Share on other sites More sharing options...
Omron Forums Support Posted October 31, 2011 Share Posted October 31, 2011 According to your description and assuming I2t settings are correct, my guess is this may be related to the accumulated error in integral registers, can you please check Motor[x].Servo.Integrator and Motor[x].Servo.Xint before the fault happens.Although the servo algorithm llimits saturates both these values with Servo.Maxint value for integral anti-windup, (and the servooutput will be limited also) this still may cause an I2t fault if it is saturated for a while. You may test this hypothesis by either decreasing your integral gains or the integrator limit. Link to comment Share on other sites More sharing options...
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