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Unread 01-04-2013, 10:10
Jefferson Jefferson is offline
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AKA: Jeff Clements
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Re: Voltage Counts Range 0-970

Quote:
Originally Posted by Al Skierkiewicz View Post
Jeff,
Those should be fine but be aware that the rapid move from +V to 0V might occur at too high a slew rate to be used by the analog module without some filtering.
Al,
I really think my issue is in the control system hardware (see Joe's post above and my response below). But to confirm this I am going to short the 5V supply to the signal wire to see what reading we get. If it is in the 970 range, that takes the encoder out of the equation. I'll post results here.

Quote:
Originally Posted by jhersh View Post
Is there any reason you are not using the GetVoltage entry-point?
Joe,
Like RufflesRidge said, the PIDController uses values instead of volts for the source. I had considered changing it to volts (we have used volts for years prior), but decided that the counts should be the more "raw" reading. One less calculation between me and the raw reading must be a good thing... or so I thought.

Quote:
Originally Posted by jhersh View Post
That will take into account factory-calibrated scaling coefficients unique to every module. You will get far more accurate results using that method. At the very least, try that and see how closely it matches your DMM at that max value.
This is very interesting. I saw your post a little late in the night to try anything last night, but I'll give it a try tonight if we're not too busy getting ready to go to Razorback.
Are you saying that it is not unexpected to get something other than 1023 when we supply 5V to the module, and the error is corrected when converting back to the voltage? If so, that's a really good reason to go back to voltage, and the PIDController should probably be changed for future seasons.
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