[StepDIR]

Can a VSD-E run open loop by controlling the VSD-E with another motion controller or does it require feedback to run? I am planning on using a Galil motion controller to drive two VSD-E drives.

Thanks,
Jay

[Montabelli]

what kind of motors are you planning to run? you can definitely run open loop back to the controller, closing the loop in the vsd drive. I think you can run a step motor but I am not sure. step motors with encoders back to the vsd will work. I have an old motion master with ac servos that I ran step and direction with mach 3 for a while. I am now running them with camsoft through a galil board.

[Al_The_Man]

If you do not close the encoder loop back to Galil, you will have to set the card for stepper mode.
IMO it would be a shame not to use the Galil PID servo loop?
Al.

[StepDIR]

I am hoping to use the Galil for closing the loop, not the VSD. I am running brushed DC servos. Can I do that and NOT connect the feedback to the VSD only to the Galil?

[Al_The_Man]

I see the VSD has encoder pass-through, but I have never used the drive so I cannot confirm if the loop can be closed solely in the Galil?
Al.

[Montabelli]

can you run the galil in step and direction mode with servos? I know you can with the vsd drives, but it would never have occoured to me to run step and direction from the galil.

are you writing code to run the galil card?

[StepDIR]

There's an idea Montabelli. I will need to see if the Galil can output step/dir and accept feedback from the encoders. I'd bet it can.

As far as writing the code for the Galil card, no. I plan on using Mach3 to send the step/dir information to the Galil using the Mach3 plugin and let the Galil convert that information to linear interpolation moves.

So my system, as of right now, will be a PC running Mach3 with an ethernet network connected to the Galil with the VSD-E drives, and also a DL06 doing all of the interlocking and control of the other machine equipment.

[Al_The_Man]

To my mind using a Galil card with all the PID power, which you cannot use in stepper mode, is a bit of a waste?
I have always used analogue drives in the torque mode.
Al.

[Montabelli]

Then galil card can do that, a smooth stepper is cheaper, unless your have already invested in the galil card. I ran my mortionmaster with a smooth stepper and the vsd xe drives for about a year before I switched. the vstd has very nice tuning facilities in it, and the usb breakout board for mach 3 works quite well. mach 3 has speed issues, the annoying windows interrupts would not let me run my machine at full resolution with out a smooth stepper.

The galil card can do the stepper mode with encoder correction, but you may end up pitting one smart system against another. Galil tuning is great too.

[keebler303]

I don't see why you can't just run the VSD in torque (current) mode and close the position loop in the Galil card. The VSD will still need the encoder for commutation, but you can do the actual position control with the galil.

Matt

[StepDIR]

Matt, are brushed DC servo motors commutated (if that is a word) by the drive? If not then maybe the VSD doesn't need the encoder?

Al,as far as the input signal to the VSD, does it really matter if its -10/+10, PWM, step direction? They're all some sort of digital signal, even the "analog" -10/+10 is produced by some digital to analog converter isn't it since the VSD is a digital device?

Boy I am learning a lot and having fun at it. Lots to think about. Thanks for all of the input.

[Al_The_Man]

DC motors are 'commutated' in the motor, by rights you do not need a PID drive when using Galil, the non-Dsp drives from A-M-C or Aerotech would work, which incidentally, their BLDC drives will also run a DC brushed motor.
I don't know the inner workings of the VSD, but the typical torque mode amplifier is a Transconductance amp where the motor current is proportional to the analogue voltage in.
Al.

[Xerxes]

DC motors are 'commutated' in the motor, by rights you do not need a PID drive when using Galil, the non-Dsp drives from A-M-C or Aerotech would work, which incidentally, their BLDC drives will also run a DC brushed motor.
I don't know the inner workings of the VSD, but the typical torque mode amplifier is a Transconductance amp where the motor current is proportional to the analogue voltage in.

Exactly.

BLDC motors require encoder to be fed to VSD even when closing loop outisde. This is because drive must know motor angle to commutate the windings.