Servo Control Software

[flash319]

I am building a 4X8 router table using servo motors and drives. I am looking for the best PC software to use with this setup that is not going to break the bank. I have been reading into Camsoft and have downloaded Mach3. I like the look of Mach but the Pulse/Direction control has me worried as it is not closed loop. What have others used and what would be recomended?

[unterhaus]

If you want closed loop you should look at EMC. You have to use linux, but it's provided. www.linuxcnc.org

Windows is not going to do closed loop in software without a major $ investment in a real-time extension.

I must say, closed loop is not all it's cracked up to be. If you are losing steps, you have a problem that is not going to be solved by going closed loop.

[Torchhead]

The "loop" on a servo system can be closed at several points. While the control software is one, another logical place is the Motor drive. Hardware loop control is closer to the motor and there are no added delays in response through a software interface (that may be doing lots of other things).

The Gecko 320/340 series of drives are closed loop. It will adjust for small errors along the run and if the error becomes too great the drive faults (stops) which is probably better than trying to force it outside the normal working envelope. Lets say your cutter jams and causes the lag error to build. Would you have it:

A. Keep adding in power until something breaks or
B. Stop and force an e-stop to the machine to prevent damage to the workpiece, machine or operator?

If you combine the Gecko 320 drives with our PSC650 or PSC1500 Power Control unit and it's Gecko Interface cards (with differential inputs for the encoder) then a fault on any drive in the cluster will instantly shut off DC power to the drives, load and discharge the Motor DC source, and issue an e-stop to MACH at the same time.

Tom Caudle
www.CandCNC.com

[flash319]

Well I am using an AB Ultra 3000 and a Parker Max FLX servo drive. I still need to get the Z axis. These drives will run with a Pulse/direction inputs but I am unsure how the drives use this for position control. I guess I can set up what that "pulse" is in real encoder values thus the drive will know the error if any. I will have to see once I start to set it up.

[Torchhead]

Well I am using an AB Ultra 3000 and a Parker Max FLX servo drive. I still need to get the Z axis. These drives will run with a Pulse/direction inputs but I am unsure how the drives use this for position control. I guess I can set up what that "pulse" is in real encoder values thus the drive will know the error if any. I will have to see once I start to set it up.

The key is WHERE the encoder feedback goes. If the encoders are tied back to the drives then the loop is closed there...just like the Gecko, Rutex and other lower cost servo drives.

TOM CAUDLE
www.CandCNC.com

[Al_The_Man]

I believe the Ultra 3000 use commisioning software to set them up, the encoder does go back to the drive, and IIRC there is also a psuedo encoder output for true closed loop controllers.
Al.