Open Loop Problem of PCI-7344

[redfield]

Dear Partners

I have a big trouble....
Any suggestion would be appreciate!

Here is the hardware and software that I am using
 S/W : MAX 3.1.1

           LabVIEW 7.1
           NI Motion 7.0

 H/W : PCI-7344
           UMI-7764 
            YASKAWA Servo Driver

I've tested my motion B/D step by step

  1) Start Max3.1.1 / MySystem / Devices and Interfaces /NI Motion Devices /
       PCI7344(1)/Interactive/1-D Interactive
  2) Slect "OPEN LOOP"
  3) Input steps : Velocity, Acceleration, Deceleration
  4) Input steps : Target Position = 100000
  5) Click  "Apply"
  6) Click  "Start"

But sometimes it stops generating steps.
it occurs very very irregularly.
I can't understand because I use "OPEN LOOP"
and "Current Trajectory Position" must increase until "TargetPosion" whether the asis move or not.
Also there is no limit signals..

Please see the image file attached.

It's very simple I control motion b/d with OPEN LOOP MODE.

and, I think the servo Driver works well because command steps and encoder pulses are equal.

Please Help me!!!

Crane

[Jasper S]

Hello Crane,

Looking at the picture you attached to your post it appears you are working in Windows Vista.  If this is the case, you should be aware that there are no currently supported NI Motion drivers for that operating system.

It also appeared that you have very high values for velocity and acceleration, which could be a cause of your trouble.  Do you still see this behavior when you use lower values for velocity and accleration?

When the motor stops moving, does it appear the operation has completed in software, and simply failed to translate into hardware steps?  Or, does the step count freeze?

Have you checked the status registers on the card?  After selecting the card in MAX you will see a status tab that contains all the flags for the card.  Checking for a modal error on the FPGA and for a move complete status could shed some light on this issue.

Regards,

Jasper S

[redfield]

Thank you Jasper S.

I think you understand me well.

I tell you more informations.  

1) The computer is working in Windows XP Professional (Just Theme).

2) It happens also at low velocity and acceleration.

3) I think when the motor stops moving, it fails to translate into hardware steps.

  Because when the motor stops, "Current Trajectory Position" and "Encoder Counts" are equal.

4) I checked status registers on the card when it works abnormally, but can't find any error message and flgs.

5) To make matters worse it happens occasionally, so it's difficult to find out the reason.

6) Strange as it may sound, when I touch the motion connector correctly,  the abnormal behavior frequency decrease.

  So I tried to exchange a new motion b/d and a motion cable but it was just same error situation.

  I can't understand because I just use "OPEN LOOP",  it is no matter whether servo driver works well or not.

7) Do I have to change PC? I already tried to exchange PCI Slot position.

I need more information about this.

I'm in trouble because this system is operating at foreign country.

It is fatal error  even if it happens once per day....

Please help me once more. Thank you.

[AnalogKid2DigitalMan]

I may be off the mark here, but it appears you are trying to control a SERVO motor with a STEPPER motor configuration.

[Brian_Beal]

Many servo drives offer stepper type inputs.  This is mostly so that a PLC type device can control a servo. 

[AnalogKid2DigitalMan]

Brian:

Point well taken, I was unaware that some drives took pulses in, I'm strictly a +/-10V servo input guy.

-AK2DM

[Jasper S]

Crane,

It is interesting that you noted that when you touch the cable, the errors happen less frequently.  This leads me to believe that there is still a problem with the connection somewhere.  It sounded like you have changed out the card and the cable, have you tried changing these out one at a time (just the cable or just the card)?  Connection errors are very hard to diagnose, so you should go through every point of connection in the system and verify you don't have any bent pins, and that everything fits together smoothly.

Besides cabling issues, there may be an issue with the drive.  What specific Yaskawa drive are you using? Does the drive display an error (the Yaskawa drive I am familiar with has some 7-seg's on its front panel that display error codes)?

Also, just verify that you do not have any software limits set up.

Regards,

Jasper S