following error

[tmoodley]

Hi,

I have a perculiar error.

Im using a UMI-7774 and a PCI-7344 motion controller with a Compax C3 servo drive. the drive feeds back a simulated encoder signal (digital RS422 5V level differential).

I have a problem with the Axis 1 on the UMI. The encoder feedback does not update in the 1-D interactive on MAX. On the 3 other axes the feedback works fine with the same drive and motor setup. The settings for all four axes are identical. On axis 1 I keep getting a following error. The problem is the feedback does not update the position.

The only noticible difference between Axis 1 and the other three is the PWM settings option. I have disabled this option.

Any suggestions as to why Im not getting feedback on Axis-1?  

[Jochen]

As the other axes work fine this could be either a problem with the drive (encoder emulation), the 7344 or the UMI.
Here are some things to check:

1. Have you monitored the emulated encoder signals with an oscilloscope? Are they ok?
2. Please wire one of the working axes to the connector of axis one and the one that is not working to another axis on the UMI. Does the error stick with the motor/drive or with the axis on the UMI? This should tell you where to look for the error.
3. If the error sticks with the motor/drive please check the settings, cabling and so on. If it sticks with the axis of the 7344/7774 please double check your MAX settings first. If you really can't find a significant difference (e. g. disabled axis, wrong feedback type,...) there is a chance that either the 7344, the 7774 or the cable are defective. In this case please contact your local NI branch for an RMA.

Best regards,

Jochen Klier
National Instruments Germany

[tmoodley]

Thanx Jochen,

I have checked the same cables, drive and linear actuator setup on the four axes of the UMI. So it seems like either the UMI-7774 or the Ni-7344 controller. The contol signals on axis 1 seem to work fine. The feedback seems to be the only problem. Is there way to id whether the fault is on the 7774 or the Ni-7344?

Regards

Thivash

[Jochen]

Thivash,

in this case the easiest way to tell which device is defective would be to exchange one of the components by another one. If you don't have a second 7344 or a 7774 you could ask your local NI branch if they can loan you these devices. The alternative is to send both to NI for a check/repair.

Regards,

Jochen

[tmoodley]

Thanx Jochen,

i have contacted Ni in S Africa. I will send both the UMI and controller to them to trouble shoot

[mayihelpu]

Hi,

Has your problem been solved.If Yes, it's good. But If No, then check out for the encoder frequency of individual axis. This may be creating some problem.

regards

Manish karnik

Application Engineer

Cruiser Controls

Mumbai, India

[tmoodley]

Hi

the problem with regard to the following error has been solved. It was a faulty UMi 7774.