Gray Code and RSLogix 5000

If you need to leave an indication of 0 at the same rotation point then test for 0 and if so transfer that to the result else subtract the indication from 360 and store the result.

Yeah... that's almost how I ended up doing it.

Attached is the code I downloaded into the MicroLogix 1100... that lowered the scan time back down to what it was before, as well. The encoder we usually use is the Koyo TRD-NA360NWD from Automation Direct, by the way.

EncoderLogicReversed1.png
 
Thank you for that explanation.

What is I3 input? 1762-IQ16?

What's the maximum speed for this application?
 
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Thank you for that explanation.

What is I3 input? 1762-IQ16?

Exactly.
And the GCD instruction takes up the whole I:x.0 word, so even though the encoder uses only 9 bits, I:x/9 through I:x/15 are not available for anything else to use. I have not tried GCD on, say, half of a 1762-IQ32T card.

What's the maximum speed for this application?

What we track (the 'work' cycle of 6 or 8-spindle automatic lathes) is typically 4-10 seconds (an eternity compared to high speed counter uses); But it's much faster to tweak degree windows via the touch screens rather than pulling safety covers, then changing cams or moving proxes/limit switches/actuators.
 
You could use an AND of 511 after loading the full input card value to preserve the lower 9 bits leaving the upper 7 free for other uses. Regarding the 76, the active counts are centered on the 0-511 leaving 76 counts on either side. Thus the 0 and 359 counts are still one bit change different preserving the essential quality of Gray encoding.
 
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