Friday, September 28, 2012

Nav Class, Day Last

Woosh!  That went by quickly.  So much information, my brain runneth over.

I can't so much remember what we did today.  I think we started off talking about the "find sensor" cue type.  It's used for rezeroing an axis.  We also talked about wiring in, mapping and scaling the absolute encoder.  This was followed up by going into the lab and doing the actual absolute encoder installation and then calibrating it (that's the scaling part).  After that we wrote cues such that from a power up where the device would not know where it was we could dependably get to a sensor, rezero, and move to a home position.

I guess rezero isn't a real word.

The afternoon was largely "go back three spaces."  We didn't unwire anything (thank goodness) but we did strip away everything in the computer such that we had to reconfigure the system from scratch.  That's reinstalling the I/O Bus, map all the cards, find and assign all of the devices to their proper inputs & outputs, and label and tag all of that in the machine.  From there we reinstall the Axis I/O device, mapping all of the K-Bus items to the correct corresponding Axis I/O features.  Once that's done all of the settings need to be addressed: velocity and position references, scale the encoders and set the wrapper values.  Finally rewrite the cues and rules to restore the functionality we had before lunch.

That list is likely missing several items, and that is indicative of our success level.  We got stuck a few times.  It was hard to find some of the inputs & outputs.  In the end we got the thing working, but had it been a day of show disaster where Kevin and I had to get the thing repaired - we wouldn't have been able to do it ourselves.  Probably too much to ask for of a 4 day class.

We had some time left at the end so we talked about targeting and PID - how to make the unit find its spike smoothly and quickly.  At the outset we were typically missing by 0.03 feet.  After tuning we got it down to a repeatable 0.001 feet.  Not bad.

The last thing we talked about wasn't really part of the class.  I was sent here with a mission to discover if and how Navigator could send position data to a projector to update focus based on a moving target.  It is possible and we went through how to do it.  I am not confident I will remember any of it though.

Really, really good class.  Highly recommended.

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