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Unread 18-09-2005, 23:37
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Re: Testing and Cause of Failure for Encoders and Hall Effect sensors

Quote:
Originally Posted by Alan Anderson
The RC analog input is ten bits, giving 1024 steps. The simple definitions in the default code throw away two bits of resolution in order to emulate the pre-2004 system, but the full range of values is available just as easily.
Somewhere along the line this info seems to have gotten garbled or missed entirely by our team. Either that or I just didn't get the info from the right guy. While I'm a mechanical sort of guy, I have helped design and control process equipment. Due to some very bad experiences I absolutely hate input sources that give me back only 1 and 0 for non-binary input. For a temperature I don't want to hear from the sensor "The temperature has increased 3.7 degrees in the last 2 minutes." That may be an important secondary factor, but what I really want is "The temperature is 253F." If the rate of increase is important I can track that by comparing subsequent readings easily enough.

Encoders can tell me how fast something is moving, and how far it has moved from the start point (assuming the integration routine is working and nothing has been skipped) but they will not tell me absolute position. (unless I use a very special encoder which is out of our price range as I recall) Since position is what I'm trying to control, I'd rather work with a directly correlating signal than deal with trying to integrate or differentiate to get what I really need.

Do I just have to change the variable definition to increase the bit size?
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Christopher H Husmann, PE

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