basic velocity distance query on 7332

[SeanJ]

Hi

I have a motion system featuring 7332/ UMI 7772/ nema 34 encoder/ N31HRLG & P70360.

I have two major issues.

1. Velocity is wrong.

If I try to set the velocity to 100 step/sec with 200steps/revolution it run at 93 step/s

2. The distance does not correspond to the velocity.

In the attached velocity graph, measured in MAX

distance = 8.1 * 93 = 753 steps

In the attached distance graph total distance = 1000 in 8.1s!!

In order to break this down to it's simplest component.  I have remove everything except the 7332.

I would have assumed the 7332 could theoretically run ok but the results show otherwise.

Does anyone have any ideas where I have gone wrong?

Sean

[SeanJ]

I just decided to run the 7332 as follows:

velocity = 1,000 step/s

distance = 20,000 steps

The graph is attached.  It is interesting to note that the time period on the graph is approximately 16.1s

I timed it on a stopwatch and got 20.6s, (when taking acceleration, deceleration, human error in account this result is pretty much bang on.)

Perhaps MAX is not working correctly?  Is this a bug?  Does it happen with the VI's too?

[SeanJ]

I tried Using motion assistant.

I've attached a graph of MAX versus Motion Assistant. 

The time periods are different. 

Motion assistant matches my stopwatch.

The answer to my question appears to be:

MAX doesn’t work – use Motion Assistant.

I've wasted days trying to get this to work! Can this really be the answer? 

[MahdiehG]

Hi Sean,

Perhaps it's your settings in MAX that is causing this discrepancy. Please follow this guide to choose your settings: http://zone.ni.com/devzone/cda/tut/p/id/3367#toc1

I thought you might find this useful as well: http://digital.ni.com/public.nsf/allkb/899AE29CB4E3578B8625709D0070A725?OpenDocument

Let me know how you get on.

Regards,