Hi Peter,

If it is edge sensitive then as you say, inverting the signal has little 
effect. I was going by your previous statement where you said it was 
dependent on the state. After doing more tests, noise looks to be a 
possible culprit. It seems odd that I have a relatively bad noise 
problem on the index while A and B are fine. They all run down the same 
screened cable. I ran some tests and the other axis also very 
occasionally misses. Neither axis loses position while running so A and 
B don't seem to be affected.

 From your docs, A and B are filtered. Does Z have the same filtering? 
The 7i29 has a relatively long ribbon (about 4') so it may be that it is 
picking up noise. I will first add some common mode chokes to the 7i29 
motor outputs (works well for Geckos and Rutex drives). If that has no 
effect I'll try moving the encoders to the 7i33. That would entail a lot 
of rerouting and remaking cables so it would be a last resort.

By the way, when the encoder inputs are set up for complementary 
signals, what happens if one wire becomes disconnected? Is there a fault 
signal?

Les


> The hardware works (just tested SV12 encoder 5). There may not be much 
> apparent difference between inverted or non-inverted index because they are 
> both edge triggered. It looks like the driver does not set the ABGateIndex 
> bit 
> so what I said about index happening all the time with the wrong index 
> polarity would not happen, just the home position might change by a count or 
> 2 
> depending in index width (assuming a normal rotary encoder short index).
> 
> If swapping the leads solves your problem, it might be electrical 
> troubles. The current driver not setting ABGateindex means a narrow index 
> pulse would work regardless of polarity though the home position would 
> change slightly depending on whether the rising or falling edge generates 
> the index event (since an edge is always needed)
> 
>

------------------------------------------------------------------------------
Enter the BlackBerry Developer Challenge  
This is your chance to win up to $100,000 in prizes! For a limited time, 
vendors submitting new applications to BlackBerry App World(TM) will have
the opportunity to enter the BlackBerry Developer Challenge. See full prize  
details at: http://p.sf.net/sfu/Challenge
_______________________________________________
Emc-users mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/emc-users

Reply via email to