Newport ESP300 & MFA stages

[James_sgp]

I am having a problem with moving the stages from the home position.
I perform a 'Find Home Signal' operation, and all the axis home ok.
When I then try and perform an Asolute Move, I get a Hardware Limit
Error and the stage stops moving. It seems to be random, as sometimes
everything is fine; after I home everything again I get the problem.

I`m pulling my hair out with this, what am i doing wrong...?


James
(Singapore)

[J.Harv]

James--

      I am not sure that I am able to see what the problem is from the information given.  Do you have a home switch set up physically? and do you also have physical limit switches?  In order for the "find home position" function to work correctly limits will need to be set up.  This could be one issue.  Please, provide a little more information about the version of Motion you're using, the type of card and motor.  How are you calling these moves?  from MAX or LabVIEW.  What type of encoder are you using?  Anyway, please let me know and I will certainly try to help you figure out what's going on here.  Thanks!

Regards,

John H
Applications Engineer
National Instruments

[James_SGP]

I am controlling 2 Newport MFA-CC stages using a 3 axis Newport ESP-300 controller via PC using GPIB, these are under the control of a Labview program.

The stages have hardware limit switches and optical encoders (I think).  As I had mentioned I execute and OR4 command which the Newport manual states as 'Find Negative Limit Switch'; it zero`s the display and everything is OK.  The problem comes when I ask the controller to move the stage to an absolute positions using PA10 command (which should move the axis to 10.000).  After moving a distance of about 0.1mm raddomly stops and give an error "Hardware Limit Detected".

I have tried lots of methods, but as I need to home the stage to a mechanical point I seem to be stuck.

[nayer]

Hello James,
How do you configure your hardware? and what driver are you using.
Thanks
Nikhil A

[James_SGP]

I talk to the controller using a modified version of the Newport VI (due to issues & limitations with there original).  Communicating with the controller seems fine, I`m not sure I understand your question about configuration?

[MissyS]

Hi James,

Where did you get the drivers? From Newport or elsewhere? What modifications did you have to make? Is the only connection to the computer using a GPIB controller in the computer?

You may want to contact Newport for additional support. Do they have an example program or utility (not necessarily using LabVIEW) that you can run? This way we can confirm that the hardware connections are correct before trying to tackle software issues. I hope this helps!

Regards,

[James_SGP]

Missy,

Thanks for the suggestions, I have contacted them but there support is pretty slow.  I can send absolute & relative move commands at any other time without a problem.  The modifications I made to Newports VI's where to wait for commands to finish before executing the next; else I get a comms error.  As it is an intermittent problem on either of my 2 stages, I have the feeling that it is unlikely to be software related; would you agree?