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List:       comedi
Subject:    RE: What does the "range" variable do in comedi_data_read ?
From:       "Caleb Tennis" <caleb () aei-tech ! com>
Date:       2002-06-03 14:19:54
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> Can somebody tell me what  does the "range" variable do in the
> comedi_data_read function?
> Does it set the channel gain to pow(10, range)? It only works with
> values 0,1,2,3. After that I get
> an invalid channel range error.

It depends on your board.  Most boards have multiple voltage ranges that
they read from, and this selects which ranges it uses.  On my PCI-6023
board, it breaks down like this:

Range 0: [-10V to 10V]
Range 1: [-5 V to 5V]
Range 2: [-1 V to 1V]
Range 3: [-.5V to .5V]

At least I think it does - I may be off on those last ranges.   Yours will
vary based on what manufacturer and part # of board you have.  Use the
'info' demo program with comedilib to find out what ranges your analog in is
capable of.

Caleb



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