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Author Topic: AxisWorks tuning  (Read 18318 times)

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Re: AxisWorks tuning
« Reply #30 on: September 19, 2010, 09:58:57 AM »
I'm using 2MHz dspmc and servos with 3000rpm so my max speed is 3000 devideed by 10 (planetary gearbox 10:1) is 300rpm of the pinion . So 300rpm * 133,33mm = 39999 mm/min max speed. 39999 mm/min devided by 60 is 666,65 mm/sec. 1mm is 750,018 counts. 750,018 * 666,65 mm/sec = 499999,5 counts per second (max). If my calculations are correct I'm using 4 times lower limit than max limit of dspmc. It looks like you have done calculations correct.
Re: AxisWorks tuning
« Reply #31 on: September 19, 2010, 01:18:47 PM »
I've devided the speed of the motor not counts. 100.000 counts per revolution of the pinion gives 750,018 counts per 1mm.

Hi pete, Let's try it this way.

If your motor was to spin 3000 rev/min (RPM) at 10,000 counts/rev = 30,000,000 counts/min div by 60 sec/min = 500,000counts/sec  or .5Mhz encoder speed. You should easily be able to spin the motors to their max rpm and still stay well within the max encoder frequency.

So my earlier math was incorrect. I came up with a max rpm of 1200 rpm with your encoder counts but it is really 12k rpm with a 2mhz freq and twice that with a 4Mhz freq.

You can either spin stupid fast or go with much higher resolution encoders to get up to the max limit. With your setup you should be just fine.

Mike
We never have the time or money to do it right the first time, but we somehow manage to do it twice and then spend the money to get it right.
Re: AxisWorks tuning
« Reply #32 on: September 30, 2010, 04:00:28 PM »
Hello,

I've tried the new firmware from Rufi and it looks a lot better than before. CDFF gain is 0..15 for IIR filter setting to smooth the output. High value will smooth more but the PID response will become slower. I have settled in smooth level 5. It works a lot better in voltage, torque and velocity mode.  I'm now trying to tune servo drives in velocity mode in which was previously impossible. If i'm not using smooth level (cdff) i get follow error right away and can't tune out, but with smooth level 5 I can get tuning a lot better.
Can somebody please help me understand PN17 parameter on page 37 on the manual of my servo drives and how do you properly set it.

Peter
Re: AxisWorks tuning
« Reply #33 on: October 01, 2010, 07:17:58 AM »
Here is what the manual says.

Torque/Speed Scale
● In velocity control mode(MD=2), this parameter set the scale between analog input voltage and parameter VM.
● In voltage control mode(MD=3), this parameter set the scale between analog input voltage and output voltage of driver.
● In torque control mode (MD=4), this parameter set the scale between analog input voltage and output torque of motor.

Here is how I see it.

All it does is set the scale of the analog input voltage to one of the parameters that you have previously chosen.

Lets take torque mode as an example. I use +-10v and a scale factor of ten
All it really does is say that if your analog input is 10 volts, give me 10V Times the scale setting, 10 = 100% of the motors torque. So at a analog input of 5v we would get 50% of the motor torque.
If your max analog input was only 5v we could possibly set this to 20 and still get 100% motor torque at only 5v.

In voltage mode we would get analog input of 10 x 10TSC and we would get 100v . Set the scale to 20 and you would get 200v output.

In the velocity mode of operation you are setting the scale of the analog input voltage in regards to parameter VM.
HTH
Mike
We never have the time or money to do it right the first time, but we somehow manage to do it twice and then spend the money to get it right.
Re: AxisWorks tuning
« Reply #34 on: October 09, 2010, 07:57:32 AM »
Ok thanks will try that and report.