uzi
New Member
Posts: 3
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Post by uzi on Jun 4, 2016 5:01:46 GMT
Hi, Using Fabi's tool we managed to configure the PID values however we are still getting oscillations. When putting weight on the platform and measuring using oscilloscope, we can see the values from the feedback encoders are changing (encoders resolution is 4K) but for small changes there is no output to the VFD. Changing the feedback limits between 1% - 10% didn't help. Attached is the current config and also you can see videos of the issue here click for videosAny ideas? Cheers, Uzi
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Post by tronicgr on Jun 4, 2016 17:22:30 GMT
Hi Uzi,
Sorry for the delay. I'll get back to your emails and the issues here as soon as I can.
Thanks Thanos
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Post by paulg100 on Jun 4, 2016 22:01:52 GMT
an I of 235 seems really high especially with a P on the higher side., are you sure the platform is not overshooting? from my limited experience it looks like its missing home, then coming back, missing then coming back etc?
im getting closer with my own PID but its not quite there yet, i started with a high I like yours and found that knocking it down significantly really helped.
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Post by tronicgr on Jun 5, 2016 15:08:57 GMT
Indeed, the I is very high and would justify this kind of oscillation. The purpose of I is to "kick" the motor if the setpoint is not reached over time (constant error).
I would suggest leave I to 0 and perhaps set D near 0 as well.
These values have best effect in fast motors, where AC motors with 20rpm max output are considered slow.
Thanks Thanos
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Post by charlesbose on Aug 6, 2016 6:54:51 GMT
Hi everyone..i am a new user here. As per my knowledge one seems really high especially with a P on the higher side. Are you sure the platform is not overshooting? from my limited experience it looks like its missing home, then coming back, missing then coming back etc? I m getting closer with my own PID but its not quite there yet, i started with a high I like yours and found that knocking it down significantly really helped.
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