Third party software and hardware support forums. > CS-Lab
IP-A and Servo drives, voltage matching...
Davek0974:
Is it possible for some kind soul to explain if I have any issue here or not please... :)
I have 3000rpm AC servo motors and they are controlled by 10-0-10v from the IP-A as normal.
However, I have my motor tuning velocity set to 3000mm/min as its not a very big mill and pretty old.
With the lead-screws I have (inch) they are 5.08mm/rev and I have 2:1 belt reduction so I think the motor will never do more than 1181rpm ((3000/5.08)*2)
Does this matter or am i ok here - I'm finding confusing info about motor tuning and matching the control signal to the speed etc.
I cant change the belt drive reduction but I have found the setting parameter for the drives that reduces the motor speed per input volt.
Thanks
mikecole:
Dave,
Most closed loop servo systems utilize amps that have tachometer feedback from the motors. Many have amps with encoder feedback as well. Also, the IP-A control can compute the RPM of the motor based upon encoder feedback. This is how my machine works. I am running at about 175imp for my rapids even though the machine is capable of running at 200ipm rapids based upon max RPM for my servo motors. So, to directly answer your question, your settings should be fine as long at your amps are getting proper tachometer feedback from the motors and as long as the CSMIO-IP/A is getting proper encoder feedback.
The automatic PID tuning worked really well on my machine. You should run the auto-tune first and see if you get good results. For me, good results were errors less than 5 encoder pulses. Make sure your amps are in good tune to start with, otherwise you will never get good results from the CSMIO/IP-A autotune.
Hope this helps!
Mike
Davek0974:
Thanks Mike
The best tune i can get is manually and gives around 300 count following error when doing rapid jogs back and forward, encoders are 10,000 count.
I cannot tune the amp to motor as it is 'supposed' to be automatic just by setting the motor type parameter, the manual is in heavy Chinglish so not much help.
The drives and motors came from China via AliExpress store.
The parameters are all there but without knowing exactly what to do, i would not fiddle with them.
mikecole:
ah bummer about the Chinglish... Some ideas for you:
Do you have a oscope? If yes you should verify the amps are seeing tachometer feedback from the servos.
Verify your encoders are 10k count or is that 10k edges? Remember that a 10k encoder would provide 40k edges which is what the IP-A cares about. That's a lot of precision!
You could also remove a belt from one of your servos and run it with a fixed DC voltage to the amp. As an example, +5vdc should spin the servo at 1500 RPM clockwise. If this is not the case you need to futz the settings for the amp. You'd need an oscope to look at the tach signal to measure RPM.
Is this a new machine your building or is it a retofit?
Mike
Davek0974:
Hi
this is a retrofit/conversion of a manual mill to cnc.
Yes i do have a 'scope but would not know how to do those tests, the encoders are 10,000 all edges, 2,500 count. I would feel certain that they are working correctly or else it would run away / fault out ?
They do run at 3000rpm for 10v input so that sounds ok?
Its just the amp pID loop that I can't tune due to the chinglish, as well as lack of knowledge.
Navigation
[0] Message Index
[#] Next page
Go to full version