02-22-2017 10:40 AM
I have a servo motor with control/driver cards designed in-house. I am wanting to write a test procedure with a GUI to test the servo motor's attributes (torque/rpm/position/voltages/currents/rotation/duration etc.). We have done this in LabWindows successfully; however, we need this servo motor to handle extreme temperatures/vibrations in a chamber and some of our instrumentation (ex. torque sensor) weren't resilient enough to handle the environment. Ideally, I would like to have all the control/measurement interfacing (cabling) go into the chamber with just the servo motor, yet still be able to capture all of the above mentioned servo motor attributes. I stumbled across NI Motion:
http://www.ni.com/white-paper/53565/en/
Before I go down this path, I just wanted to see if anyone else has used this architecture and if they think I could accomplish what I want to do. I am uncertain if you can use your own servo motor/control&driver cards with the NI Motion components to capture the motor characteristics.
Thanks,
Alex
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02-23-2017 10:40 AM
Hi Alex,
I very strongly doubt NI Motion will work well with a custom made driver card. Just to clarify, does this mean you have a custom device which takes commands from your computer and sends them to a servo drive? You can use NI Motion with a non-NI motor driver and motor (as long as they're compatible) but NI Motion is specifically designed to talk with our NI Motion cards and I would expect the driver is intrinsically linked to our hardware. In fact, the library for the driver is called "73xx", referring to the model number of our Motion cards.
02-24-2017 07:24 AM
Austin,
Thanks for the response. Our cards take a provided (external to the cards) voltage and the control card produces all of the necessary signals for the driver card to operate the servo. This information was very help, but I would be curious to know how the NI Motion architecture measures torque values? I didn't see a sensor of some sort external to the AKM servos utilized in Ni Motion. Is there something internal to the servo motor like a flange of some sort that measures this?
-Alex
02-27-2017 11:40 AM
Hi Alex,
Let me make sure I understand your system. You have a custom-made motion control card which takes and external voltage and generates signals which are sent to your motor driver, which drives your motor. Is that correct?
I believe NI Motion measures torque from an external analog input signal. It can then be configured for torque control in NI MAX. We have a brief help document on it:
Torque Control Using Monitoring Force LabVIEW Diagram
http://zone.ni.com/reference/en-XX/help/372134F-01/ni-motion_help/monitoring_force/
Typically our Motion cards have analog inputs which are used for this purpose. I would like to clarify, you are talking about NI Motion and not NI Softmotion, right? NI Softmotion is another motion control product we offer which works with our cRIO and cDAQ devices.
02-27-2017 12:42 PM
Austin,
Yes, that assumption is correct. We have power supplies that power the cards and other components inside of the servo motor. We use a torque sensor with a test fixture along with a magnetic particle brake to "fight" against the servo. We also use an oscope for some specific current measurements (in-rush current etc.), while everything is being controlled and recorded by LabWindows.
I was referring to NI Motion Control but I am ultimately looking for a better way to do this whole testing setup, so I was just dabbling in some potential options that NI provides relative to servo motors.
-Alex
02-28-2017 02:22 PM
Hi Alex,
If your custom card is an important part of the system, there may be little we can do for you. Unfortunately our software is centered on our hardware, so if our hardware isn't in the mix our drivers won't be able to do anything. If the motion system is not an integral part of your application, you could switch to our hardware and have a much easier time with setup. You would need an NI Motion card, UMI breakout board, a servo drive, and a servo motor. You would also need the cables to connect all these things. If you're using our hardware, it all works together naturally so the setup process takes far less time. You already have a servo motor and servo drive, so you may just need a few more components. If you did use NI Motion, you could do torque control from an analog signal as shown in the help document below:
Torque Control Using Analog Feedback LabVIEW Diagram
http://zone.ni.com/reference/en-XX/help/372134F-01/ni-motion_help/torque_cntrl_lv_diagram/
If you are not using our Motion card, I don't think there is much the NI Motion driver can do to help you. We appreciate your consideration!