Pci-7352 control motor to move as sinwave profile with Kollmorgen'sServostar600 servostar

[Taccine]

How to use Pci-7352 to control motor  moving as sinwave profile with Kollmorgen'sServostar600 driver?

I  write out a sine wave on one of the analog output channels with DAQ card. But from feedback fo encoder the motor ddoes not rotates as we wante.And the center of rotaion is swifting from here and there  .Who can tell me how to design carefully the motion ?

Thanks.

[Jochen]

The best way to run a sinusoidal motion profile is using contouring. In contouring mode you provide an array of position data to a buffer on the PCI-7352. The PID controller on the PCI-7352 makes sure that the motor follows this profile closely. Please refer to the online help and the shipping examples to learn more about contouring.


Contoured Move

Kind regards,

Jochen

[Brian_Beal]

I have attempted what you are trying with a Delta Tau controller with very poor results.  When you use a controller in "direct drive" mode, an analog input can be mapped to either commanded speed or commanded position.  There is no motion profiling occuring, so any change in the voltage results in an immediate attempt to move the motor to that new position.  The result is a lot of jitter, and most likely an overcurrent trip on the drive.  Filtering is usually available, but the result is sluggish performance.  I ended up writing a Labview program that generates the motion code based on the sine wave parameters that the user entered.  It is best to use camming, or profiling, and just generate a number of points that the motion controller will interpolate between.

[Jochen]

Brian,

I think the PCI-7352 works a bit different. In fact the contouring data replaces the trajectory generation of the NI-Motion board. The contouring data need to be provided in an equipdistant position over time format. That means data is provided in a format like this:

x1           x2           x3           x4           x5...
10 ms    20 mx     30 ms     40 ms    50 ms....

In between these position points a spline engine interpolates the position data to match the timing of the contouring array (10 ms in this example) with the timing of the PID controller.
The contouring data is not sent as a voltage directly to the analog outputs of the board but it generates a continuous motion profile for the PID controller. Thus the quality of contoured moves is very similar to the quality of any other move type. Contouring is used with NI-Motion boards in high-speed cutting machines and laser labelling applications.

Jochen

[Brian_Beal]

Jochen-

They both work the same way, it is just that NI calls it contouring instead of camming.  I'm not sure that the 7352 can do the direct drive, but as I noted, I wouldn't recommend it.

Brian

[Taccine]

I find the profile seems working properly at lower freqency sinwave analog  input under contoring mode .the result determined by the timer of  contoring mode  when old data time usually sets to 10 ms and interval time to 10ms. I means to  control motor move as higher sinewave profile  more than 10Hz frequency.Must i use position close-loop ?

[Jochen]

Taccine,

10 Hz seems to be a reasonable limit for a contoured sine wave. 10 Hz means that each sine period is built from 10 position points in the contouring array. Going faster will result in a bad resolution of the sine wave.

If you need much better performance, I don't think that you will be able to reach this with a standard motion control board. Still you should check if the limitations that you are experiencing are really related to the motion control or maybe to some limitations in the drive or motor (e. g. current limits due to high accelerations or limited sampling rate of the analog input). The Servostar should provide some diagnostic features to find this out.

If the drive and the motor is not the limiting factor, things become a bit more complicated. The best option that I can think of is using an FPGA-based R Series board with LabVIEW FPGA and the NI-SoftMotion Development Module. This hardware/software combination allows you to run control loops and interpolations with more than 200 kHz. This should be enough even for the fastest cycles.

This approach is more complex than using a standard motion control device, but it is a much more flexible and powerful solution.

Jochen
P. S.: I don't understand exactly what you mean with "Must i use position close-loop?". When driving a servo with a 7350 board you can't use another mode but closed loop mode.

[Taccine]

Hi Jchen,

I'm sorry to no ideal about using an FPGA-based R Series board with LabVIEW FPGA or the NI-SoftMotion Development Module.

I've read your old bbs recentlyabout sinwave movement through alalog input with DAQ  card to  NI-motion Analog-input  terminal .This approach may be well to my built :NI-labview 8.0,NI-PCL-6230,PCL-7352,UMI-7772,and servostar 610 and my AC servo motor.The servostar 610 is set to analog torqure mode.
The sinwave movement must be control centre point  what is my " postion close-loop" .

[future_one]

hello every one

I am using pci-7352 pci-6230  servstar s614, in order to implement a sinwave movement which freq more than 20Hz,i adopt the mode of master analog input -slave axis gearing.

but when freqn more than 20Hz  the slave axis can't follow up the analog input and have a great following erro,

do you have a good method to sovle the problem?

thank you!