how do i implement motion control w/pci 6220

[tomgnyc]

I want to set up a system that generates a velocity signal from NI-DAQ via Labview. I want to control movement with the servoamplifier via resolver position feedback. This motor will be running at very slow velocity (around 1 rpm) and the velocity precision is not very important. Is this possible using the hardware and software that I have now? Can you refer me to any Labview examples that might be helpful?

Kollmorgen AKM 42G Brushless DC Servo motor w/ resolver

Servostar 606 servoamplifier

PCI 6220 DAQ card

NI-DAQmx 7.4

Labview 7.0

Thomas Ganley

[Jochen]

Thomas

in general due to the non-deterministic behavior of Windows you will never be able to create a reliable motion control system with a PCI-6220 I have answered similar questions multiple times in the forums (e. g.  here and here). Additionally there are no analog outputs on the PCI-6220 so this board can't be used anyway. The cheapest M-Series board that provides analog outputs is the PCI-6221.

On the other hand if you just want to control the velocity of your motor with the Servostar 606 drive you might be successful as this drive closes the velocity control loop by itself so the only thing you will have to do is to output analog signals. The drive will interpret this analog signal as a setpoint for its velocity control loop.
For the case that you need to control the motor's position and/or if you need safety features llike following error tracking or limit switch monitoring I strongly recommend to use a real motion control board like the PCI-7342 instead.

Best regards,

Jochen Klier
National Instruments Germany

[tom]

Jochen

Thank you for your prompt and informative response. I actually do have
the PCI-6221; that was a mistake. Your suggestion of using the
Servostar for velocity control is how we want to go due to budget
issues.
Let me see if I have this straight. I can use Labview to generate an
analog voltage signal to be sent through the PCI-6221 to the Servostar
analog input. I then scale the analog signal with the Servostar and
tweak the response of the motor with the PID controls.
If this is correct I have two more questions:
1 - Is the analog output just a constant voltage signal or will it be
in the shape of the desired velocity profile; for example, a
trapezoidal signal for a trapezoidal velocity profile?
2 - Is it possible to feed back position information from the Servostar
into Labview? (This would be for a position limit not position control)

Thomas Ganley


Jochen wrote:
> Thomas
>
> in general due to the non-deterministic behavior of Windows you will
> never be able to create a reliable motion control system with a
> PCI-6220 I have answered similar questions multiple times in the
> forums (e. g.&nbsp; <a href="message?board.id=240&amp;message.id=2401&amp;view=by_threading&amp;page=1" target="_blank">here</a> and <a href="message?board.id=240&amp;message.id=1980&amp;view=by_threading&amp;page=1" target="_blank">here</a>). Additionally there are no analog outputs on the PCI-6220 so this board can't be used anyway. The cheapest M-Series board that provides analog outputs is the PCI-6221.
> On the other hand if you just want to control the velocity of your motor with the Servostar 606 drive you might be successful as this drive closes the velocity control loop by itself so the only thing you will have to do is to output analog signals. The drive will interpret this analog signal as a setpoint for its velocity control loop.For the case that you need to control the motor's position and/or if you need safety features llike following error tracking or limit switch monitoring I strongly recommend to use a real motion control board like the <a href="http://sine.ni.com/nips/cds/view/p/lang/de/nid/13806" target="_blank">PCI-7342</a> instead.
> Best regards,
>
> Jochen Klier
> National Instruments Germany

[David S.]

Hi Thomas -

The answers to your questions will ultimately lie with Servostar's documentation, since you're asking about the inputs expected by the drive and the outputs provided by it.  However, I'll try to help out with knowledge of our products:

1. The command output from our motion control devices (the 73xx line) is a +/- 10V DC signal, whose level is directly proportional to the command given.  A velocity drive should interpret this command accordingly, though you'll have to check with Servostar to see what type of command signal they expect.
2. Our motion controllers generally receive encoder or analog feedback signals directly from the feedback device, and not from the drive.  If the Servostar drive provides feedback, you can read it in using the Analog Input (for voltage feedback) or Counter Input (for encoder feedback) channels on your DAQ device.
   

[tom]

Thank you again. This response was very informative. I think I have a
good overall idea of how to set up the system now. Thanks!