Spindle encoder setup probelms with mesa 7133
Any ideas. I have been working on this for about a month off and on.
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Any ideas. I have been working on this for about a month off and on.
What isn't happening?
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It is in RPS so will need to be scaled to RPM
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My VFD will not take - input for reverse. but it will put a center point at +5 So greater then +5 forward Les then +5 rev. and I am still not sure if the loop is closed. When start the spindle the PWM goes straight to +10 volts. Any knolage you have on this would begreat.
Jim
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My VFD will not take - input for reverse. but it will put a center point at +5 So greater then +5 forward Les then +5 rev. and I am still not sure if the loop is closed. When start the spindle the PWM goes straight to +10 volts. Any knolage you have on this would begreat.
Offset PWM is very rarely a good idea, so I wouldn't recommend doing that. (the main problem being that PWM-off is full speed reverse)
The actual PWM component does not output a negative PWM on the output pins (because no such thing exists). What happens is that the "dir" pin is set, and a normal PWM output happens.
Generally, with a VFD, you ignore the "dir" pin completely and connect the VFD "fwd" and "rev" contacts to GPIO using motion.spindle-fwd and motion.spindle-rev
This generally works, though there is scope for an issue where the system can get stuck on the "wrong" side of zero.
If your spindle is running straight to full speed then it may be that the relative signs of the spindle speed command and feedback are wrong.
What PID settings are you using? I would begin by getting the speed as close as possible using _just_ FF0 before adding a small amount of I for load compensation and non-linearity.
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Jim
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You possibly have the PID rather too active.So I have played with closed loop spindle . On my machine Where I have an older gearbox. I get alot of hunt and gear slap
A spindle speed control probably works best based around mainly FF0 supplemented by I. Pgain isn't really right for this application, as you don't want zero-output when up to speed.
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I decided to play with closed loop a bit more. What I ended up with was stable performance with tese settings.
setp pid.2.Pgain 0.000
setp pid.2.Igain 0.0
setp pid.2.Dgain 0.000
setp pid.2.bias 0.0
setp pid.2.FF0 0.00000199
setp pid.2.FF1 0.0
setp pid.2.FF2 0.0
setp pid.2.deadband 0.1
setp pid.2.maxoutput 10.00
The motor runs up to speed based on this output and that is it. If I add and "I" even in realy small amounts I get overrun and hunting. So based on what I see FF0 is just scaling my RPM to output voltage.
Jim
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I would expect Igain to be at most 1/1000th of FF0. And maybe 100x smaller than that.setp pid.2.FF0 0.00000199
The motor runs up to speed based on this output and that is it. If I add and "I" even in realy small amounts I get overrun and hunting. So based on what I see FF0 is just scaling my RPM to output voltage.
I am assuming you have a very high-speed spindle?
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