Re: [Emc-users] Servos cannot calm down -- maybe I should go away from velocity mode in amplifiers?
Igor, My servo drives are Yaskawa and it is my understanding that they close the speed and current loops, and EMC2 closes the position loop. It is important that the outside loop (position) be at least, if not more responsive, than the middle loop (speed). Maybe my settings will help you: EMC2: Max Velocity = .5 Max Acceleration = 10. P = 280 I = 3.5 D = .25 FF0 = .25 Yaskawa: Cn-03 Speed Reference Gain = 1500 AutoTune Rigidity = 4 Cn-04 Speed Loop Gain = 165 Cn-05 Speed Loop Integration Time Constant = 22 Cn- 17 Torque Reference Filter Time Constant = 4 Also, when servo tuning use the maximum velocity and view the velocity profile on Halscope. It took me many, many tries to get these numbers . . . like Las Vegas! Good luck. -Original Message- From: Igor Chudov [mailto:ichu...@gmail.com] Sent: Monday, September 13, 2010 9:37 AM To: Enhanced Machine Controller (EMC) Subject: [Emc-users] Servos cannot calm down -- maybe I should go away from velocity mode in amplifiers? I posted a message to this list that my servo motors cannot calm down after a motion. Right now my amplifiers are set to velocity mode and I use a tachometer for velocity feedback. So, the amps themselves have a velocity loop that they close. There is essentially two loops per axis, one in EMC2 and one in the amplifier. Unfortunately, my efforts to tune PID to calm the mill down, have not been successful. If I turn down the gain parameters, the mill starts getting following errors, if I turn them up, the motors have hard times calming down. If, when the mill cannot calm down, I hit F2 (which for me inhibits the amps), and then F2 again, the bothersome buzzing stops. I am now thinking that I should reconsider my entire approach and use a different mode to avoid two loops per axis. My amplifiers offer the following modes: 1) Velocity (tachometer) mode, which is the current setting 2) Current or Torque mode (amplifier controls torque/current) 3) Voltage mode (amplifier maintains voltage) 4) IR compensation (not sure what it is exactly, probably compensated for resistance losses in windings). So... Would you think that I should switch to, say, torque mode or voltage mode? Any thoughts? - Igor -- Start uncovering the many advantages of virtual appliances and start using them to simplify application deployment and accelerate your shift to cloud computing http://p.sf.net/sfu/novell-sfdev2dev ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users This communication is for the use of the intended recipient only. It may contain information that is privileged and confidential. If you are not the intended recipient of this communication, the disclosure, copying, distribution or use hereof is prohibited. If you have received this communication in error, please advise me by return e-mail or by telephone and then delete it immediately. -- Start uncovering the many advantages of virtual appliances and start using them to simplify application deployment and accelerate your shift to cloud computing. http://p.sf.net/sfu/novell-sfdev2dev ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
[Emc-users] Servos cannot calm down -- maybe I should go away from velocity mode in amplifiers?
I posted a message to this list that my servo motors cannot calm down after a motion. Right now my amplifiers are set to velocity mode and I use a tachometer for velocity feedback. So, the amps themselves have a velocity loop that they close. There is essentially two loops per axis, one in EMC2 and one in the amplifier. Unfortunately, my efforts to tune PID to calm the mill down, have not been successful. If I turn down the gain parameters, the mill starts getting following errors, if I turn them up, the motors have hard times calming down. If, when the mill cannot calm down, I hit F2 (which for me inhibits the amps), and then F2 again, the bothersome buzzing stops. I am now thinking that I should reconsider my entire approach and use a different mode to avoid two loops per axis. My amplifiers offer the following modes: 1) Velocity (tachometer) mode, which is the current setting 2) Current or Torque mode (amplifier controls torque/current) 3) Voltage mode (amplifier maintains voltage) 4) IR compensation (not sure what it is exactly, probably compensated for resistance losses in windings). So... Would you think that I should switch to, say, torque mode or voltage mode? Any thoughts? - Igor -- Start uncovering the many advantages of virtual appliances and start using them to simplify application deployment and accelerate your shift to cloud computing http://p.sf.net/sfu/novell-sfdev2dev ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Servos cannot calm down -- maybe I should go away from velocity mode in amplifiers?
Two velocity loops shouldn't be a problem. Have you tried reducing the amp gain? Somewhere the amps must have controls for the loop gain. Try turning the gain down. It doesn't matter if the amp velocity loop is a bit weak as EMC's loop will compensate. Les On 13/09/2010 15:37, Igor Chudov wrote: I posted a message to this list that my servo motors cannot calm down after a motion. Right now my amplifiers are set to velocity mode and I use a tachometer for velocity feedback. So, the amps themselves have a velocity loop that they close. There is essentially two loops per axis, one in EMC2 and one in the amplifier. -- Start uncovering the many advantages of virtual appliances and start using them to simplify application deployment and accelerate your shift to cloud computing http://p.sf.net/sfu/novell-sfdev2dev ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Servos cannot calm down -- maybe I should go away from velocity mode in amplifiers?
Two loops can be a problem the 'outer' loop has to be the master we used to tune the hardware loop really 'tight' and had jitter at the cnc control loop we ended up 'de-tuning' the hardware loop to soften it a bit ( reduced gain ) its not hard to try with old school amps with pots, a bit more tedious with software program tuning, still easy hth tomp On Mon, Sep 13, 2010 at 10:25 AM, Leslie Newell les.new...@fastmail.co.uk wrote: Two velocity loops shouldn't be a problem. Have you tried reducing the amp gain? Somewhere the amps must have controls for the loop gain. Try turning the gain down. It doesn't matter if the amp velocity loop is a bit weak as EMC's loop will compensate. Les On 13/09/2010 15:37, Igor Chudov wrote: I posted a message to this list that my servo motors cannot calm down after a motion. Right now my amplifiers are set to velocity mode and I use a tachometer for velocity feedback. So, the amps themselves have a velocity loop that they close. There is essentially two loops per axis, one in EMC2 and one in the amplifier. -- Start uncovering the many advantages of virtual appliances and start using them to simplify application deployment and accelerate your shift to cloud computing http://p.sf.net/sfu/novell-sfdev2dev ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Start uncovering the many advantages of virtual appliances and start using them to simplify application deployment and accelerate your shift to cloud computing http://p.sf.net/sfu/novell-sfdev2dev ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Servos cannot calm down -- maybe I should go away from velocity mode in amplifiers?
On Mon, Sep 13, 2010 at 10:50 AM, Thomas Powderly tomp4...@gmail.com wrote: Two loops can be a problem the 'outer' loop has to be the master we used to tune the hardware loop really 'tight' and had jitter at the cnc control loop we ended up 'de-tuning' the hardware loop to soften it a bit ( reduced gain ) Maybe I should turn the gain on the amplifier loop way down? i its not hard to try with old school amps with pots, a bit more tedious with software program tuning, still easy hth tomp On Mon, Sep 13, 2010 at 10:25 AM, Leslie Newell les.new...@fastmail.co.uk wrote: Two velocity loops shouldn't be a problem. Have you tried reducing the amp gain? Somewhere the amps must have controls for the loop gain. Try turning the gain down. It doesn't matter if the amp velocity loop is a bit weak as EMC's loop will compensate. Les On 13/09/2010 15:37, Igor Chudov wrote: I posted a message to this list that my servo motors cannot calm down after a motion. Right now my amplifiers are set to velocity mode and I use a tachometer for velocity feedback. So, the amps themselves have a velocity loop that they close. There is essentially two loops per axis, one in EMC2 and one in the amplifier. -- Start uncovering the many advantages of virtual appliances and start using them to simplify application deployment and accelerate your shift to cloud computing http://p.sf.net/sfu/novell-sfdev2dev ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Start uncovering the many advantages of virtual appliances and start using them to simplify application deployment and accelerate your shift to cloud computing http://p.sf.net/sfu/novell-sfdev2dev ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Start uncovering the many advantages of virtual appliances and start using them to simplify application deployment and accelerate your shift to cloud computing http://p.sf.net/sfu/novell-sfdev2dev ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Servos cannot calm down -- maybe I should go away from velocity mode in amplifiers?
Yes, with this loop, stability is more important than accuracy. You can still get get very good results with no velocity feedback at all. Les Maybe I should turn the gain on the amplifier loop way down? i -- Start uncovering the many advantages of virtual appliances and start using them to simplify application deployment and accelerate your shift to cloud computing http://p.sf.net/sfu/novell-sfdev2dev ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Servos cannot calm down -- maybe I should go away from velocity mode in amplifiers?
- Igor On Mon, Sep 13, 2010 at 11:13 AM, Leslie Newell les.new...@fastmail.co.uk wrote: Yes, with this loop, stability is more important than accuracy. You can still get get very good results with no velocity feedback at all. OK, I will turn the pots on amps way down and will see how it goes. i Les Maybe I should turn the gain on the amplifier loop way down? i -- Start uncovering the many advantages of virtual appliances and start using them to simplify application deployment and accelerate your shift to cloud computing http://p.sf.net/sfu/novell-sfdev2dev ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Start uncovering the many advantages of virtual appliances and start using them to simplify application deployment and accelerate your shift to cloud computing http://p.sf.net/sfu/novell-sfdev2dev ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Servos cannot calm down -- maybe I should go away from velocity mode in amplifiers?
I would turn the posts down a bit and see if it makes much difference. If it does then turn them down a bit more. If it makes no difference then it could be that the drives aren't the problem. Take a photo or mark the pots before you tweak them. That way if something goes wrong at least you knwo where they were. Les -- Start uncovering the many advantages of virtual appliances and start using them to simplify application deployment and accelerate your shift to cloud computing http://p.sf.net/sfu/novell-sfdev2dev ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Servos cannot calm down -- maybe I should go away from velocity mode in amplifiers?
Igor Chudov wrote: I am now thinking that I should reconsider my entire approach and use a different mode to avoid two loops per axis. No, I think you need to retune the Y amplifier, I think that is where the oscillation is. Just turning down both the tach and command gain should help. Jon -- Start uncovering the many advantages of virtual appliances and start using them to simplify application deployment and accelerate your shift to cloud computing http://p.sf.net/sfu/novell-sfdev2dev ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Servos cannot calm down -- maybe I should go away from velocity mode in amplifiers?
shouldn't this be done systematically? (it could be done all in emc with halscope) First tune the velocity loop in amp -send a step response to the drive (square wave) and scope the responce. -Adjust the loop gain of the amp to get the best waveform - (match the square wave the best you can) Then from that point Tune the PID FF0-FF2 I found what got me close is something Chris had said on irc. Make sure you calculate the output scale for what you want. Like for me 200ipm at .9v out (200/60)/.9=3.7 for output_scale. I made sure FF1 was 1 (set P to 10 and D to 1 iirc for starters) than I commanded a slow move (1ipm) and adjusted the gain of the amp until the following error was 0 or as close as I could get it. Instantly - my movement was smooth with no overshoot. I still need to tune better - but that sets the amp very well. sam (sorry - I seem to be rambling) On 9/13/2010 9:37 AM, Igor Chudov wrote: I posted a message to this list that my servo motors cannot calm down after a motion. Right now my amplifiers are set to velocity mode and I use a tachometer for velocity feedback. So, the amps themselves have a velocity loop that they close. There is essentially two loops per axis, one in EMC2 and one in the amplifier. Unfortunately, my efforts to tune PID to calm the mill down, have not been successful. If I turn down the gain parameters, the mill starts getting following errors, if I turn them up, the motors have hard times calming down. If, when the mill cannot calm down, I hit F2 (which for me inhibits the amps), and then F2 again, the bothersome buzzing stops. I am now thinking that I should reconsider my entire approach and use a different mode to avoid two loops per axis. My amplifiers offer the following modes: 1) Velocity (tachometer) mode, which is the current setting 2) Current or Torque mode (amplifier controls torque/current) 3) Voltage mode (amplifier maintains voltage) 4) IR compensation (not sure what it is exactly, probably compensated for resistance losses in windings). So... Would you think that I should switch to, say, torque mode or voltage mode? Any thoughts? - Igor -- Start uncovering the many advantages of virtual appliances and start using them to simplify application deployment and accelerate your shift to cloud computing http://p.sf.net/sfu/novell-sfdev2dev ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Start uncovering the many advantages of virtual appliances and start using them to simplify application deployment and accelerate your shift to cloud computing http://p.sf.net/sfu/novell-sfdev2dev ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
