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Unread 01-04-2013, 19:00
jhersh jhersh is offline
National Instruments
AKA: Joe Hershberger
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Re: Voltage Counts Range 0-970

Quote:
Originally Posted by Jefferson View Post
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.
That's in Java? C++? Both?

Quote:
Originally Posted by Jefferson View Post
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.
You are certainly not guaranteed a certain raw value for a specific voltage. That's an uncalibrated raw value. It will be consistent for a given module, though, so if you only need it to work on one module, you can figure out what raw values are mapped to what voltages, and you can use the raw codes reliably. If you switch modules, you need to figure out new raw codes again.

-Joe
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