Hello Guest it is July 17, 2019, 01:12:37 PM

Author Topic: Which servo amplifiers?  (Read 11276 times)

0 Members and 1 Guest are viewing this topic.

Which servo amplifiers?
« on: June 18, 2009, 04:38:00 PM »
I'm in the planning stages of a retrofit for my 25 year old VMC (the only unreliable machine in my shop).  It is equipped with Fanuc parts and I plan on removing everything electrical, except for the servo motors (Fanuc 'Yellow Cap' 5M (X and Y axes) and 10M (Z axis)). 

I don't want to reuse the drives because I have had some issues with them.

I am planning to use a Galil 18x6 controller with the Mach3 + Galil plugin.  From the Galil manual, it looks like the 18x6 will only output ±10VDC to the servo amplifier.  Is that the only option I have?  I see that the 18x6 will also control steppers with 5V step/dir output; can I output 5V step/dir to control a servo amplifier (such as Rutex or Viper)?

Alternatively, does anyone know of any off-the-shelf ±10VDC servo drives I could use?

Thanks in advance,
Chris Kirchen
Re: Which servo amplifiers?
« Reply #1 on: June 18, 2009, 09:09:38 PM »
Advanced Motion Controls, they have nice 100 amp peak units.
100A25's should work for those motors configure for Torque mode of operation.
Nothing wrong with ±10VDC.
The other thing you will need is fairly large Power supply(s).
Nosmo
« Last Edit: June 18, 2009, 09:13:03 PM by NosmoKing »

Offline smurph

*
  • *
  •  1,106 1,106
  • "That there... that's an RV."
    • View Profile
Re: Which servo amplifiers?
« Reply #2 on: June 19, 2009, 11:27:39 PM »
Galil has a wonderful tech support staff that will talk to you for free.  Just dial their toll free number on their website and tell them what you want to do.  You need to give them the wattage of the motors and then they may have some suggestions.  I like the Yaskawa drives.  Are your motors DC brush or brush less (AC)?

The Galil controllers will operate an analog drive (+/-10VDC) in either speed or torque control.  And they will also a operate a drive with position control (step and dir).  I would opt for analog as you can run closed loop position control.  The current Yaskawa drives will do speed, torque, and position control, so you can take your pick.  

If you are planning on using Mach with the Galil, I would suggest a Galil controller that has Ethernet.  The DMC40x0, DMC21x3, and the older DMC21x0 and DMC22x0 models.  The 21x3 controllers are "Econo" controllers, but they do the job real well.  The PCI bus based controllers work, but they complicate cabling.  An Ethernet controller can be mounted right in the control cabinet with only one wire going to the Mach host PC.

Steve
Re: Which servo amplifiers?
« Reply #3 on: June 20, 2009, 02:13:38 AM »
I should have mentioned that the motors are DC and their ratings are:
   Fanuc 5M - 9A peak, 151V, 2000 rpm, 2000 count encoder
   Fanuc 10M - 12A peak, 165V, 1500 rpm, 2000 count encoder

NosmoKing, I took a look at the AMC 100A25 drives; I think they are on their way out (their status is reserved).  I'll give them (and Galil) a call to see what they recommend.

Smurph, running one single Ethernet cable is going to be soooo much easier with my machine.  I should have thought of that, but I didn't; thank you for saving me that hassle of finding that out by myself.

I read the sticky that you posted about "Galil controller compatability" and you mention that the Econo controllers have a 350 ms delay over the Accelera controllers (because the Econo has to convert the commands from ASCII to binary).  How does this affect the overall performance?  Does everything happen just as fast, except that there is a 350 ms between when Mach starts sending the program and when the Galil starts sending signals to the drive? Or does each command sent to the Galil take 350ms to be interpreted?  I'm guessing that it's not the latter, but I figured I would ask.  Is the extra cost of the Accelera worth it?

Thanks again,
Chris
« Last Edit: June 20, 2009, 02:22:55 AM by ckirchen »

Offline smurph

*
  • *
  •  1,106 1,106
  • "That there... that's an RV."
    • View Profile
Re: Which servo amplifiers?
« Reply #4 on: June 20, 2009, 03:01:24 AM »
Chris,

The 21x3 "Econo" controllers will do binary commands.  I think only the 18x2 "Econo" PCI controller won't do binary commands.  Either way, it's 350 microseconds (us), not milliseconds (ms).  So the interpretation is still very fast in the whole scheme of things.  The way the Galil Plugin is working now, not being able to do binary commands isn't even an issue.

If you don't need the extra I/O that the Accelera offers, I'd say the 21x3 is the way to go.  You can get an Ethernet ModBus I/O device far cheaper if you need more I/O.  But I have to say that the 40x0 Accelera controllers are sexy!  I have one sitting next to me right now and it is slick.  So the Accelera controller might be worth it if you have to have the slickest of the slick.  But the power and speed of the Accelera controller is simply not needed for our application.

Steve
Re: Which servo amplifiers?
« Reply #5 on: June 20, 2009, 09:57:11 AM »
I should have mentioned that the motors are DC and their ratings are:
   Fanuc 5M - 9A peak, 151V, 2000 rpm, 2000 count encoder
   Fanuc 10M - 12A peak, 165V, 1500 rpm, 2000 count encoder

NosmoKing, I took a look at the AMC 100A25 drives; I think they are on their way out (their status is reserved).  I'll give them (and Galil) a call to see what they recommend.


BTW, Galil use AMC drives, just relabelled, although the ones they sell are too low a rating for your motors I believe.
Nosmo 
Re: Which servo amplifiers?
« Reply #6 on: June 22, 2009, 11:13:42 AM »
Forgot to point out, the later BLDC drives from AMC will drive a DC brushed just as easily, the advantage is that if wishing to upgrade to BLDC at a later date, the drives will be in place.
Nosmo
Re: Which servo amplifiers?
« Reply #7 on: June 27, 2009, 11:39:55 PM »
Yeah, I guess 350 µs makes much more sense than 350 ms.  I should have paid more attention while I read the sticky.

So, I talked to Galil and they recommended AMC because their drives max out at 500W.  AMC recommended their BE25A20AC ($539 list) and BE25A20I ($489 list) drives.  They are identical, except that the ...AC requires 130 VAC input, whereas the ...I requires 190VDC.  I think I might go with the ...AC to save me converting the machine's AC into DC.

We looked at a few digital drives, but they are approximately twice as much as similarly rated analog drives.

I have a question about the Galil.  It looks like I'm going to go with their DMC-21x3.  I would like to attach one of their digital I/O boards (DB-28040-5V) for the extra I/Os.  Can Mach3 make use of it?

Thanks again,
Chris

Offline smurph

*
  • *
  •  1,106 1,106
  • "That there... that's an RV."
    • View Profile
Re: Which servo amplifiers?
« Reply #8 on: June 27, 2009, 11:58:03 PM »
Yes, the plugin can use the extended I/O.

Steve

Offline cnc-it

*
  •  153 153
    • View Profile
Re: Which servo amplifiers?
« Reply #9 on: July 12, 2009, 06:33:10 AM »
Hi ckirchen sounds like an interesting project you have going!

I have the same servo set up on my Bridgeport BPC 320H machines.
What type of VMC do you have..?

Have you thought of sticking with the Fanuc DC drives..they are very cheap to buy on Ebay these days and the Fanuc manuals are very in depth on how to set them up.
I've found them to be very reliable...

On the Fanuc system (I presume you have 6MB??) the encoders attach to a frequency to velocity circuit on the motherboard to give speed and position.

I'm fairly new to Mach..how will you set up the encoders, i'm asking as I have a Galil DMC 1880 that I would like to set up with Mach3 and the Fanuc yellow cap dc brush motors.

John.