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<== Date ==> <== Thread ==>

Subject: RE: aiRecord, RVAL vs. VAL
From: "Mark Rivers" <rivers@cars.uchicago.edu>
To: "Amy Baum" <amy_baum@lynceantech.com>
Cc: <tech-talk@aps.anl.gov>
Date: Thu, 4 Dec 2003 16:30:38 -0600
> But this question still remains:
> 
> Amy Baum wrote:
>  >>
> >> Why is RVAL only an int type if it is intended to hold the
> >> raw data from hardware?

It is intended for devices like A/D converters that typically return 12,
14 or 16 bit integers of "RAW" values.  These values can be converted to
engineering units by the ai record if the appropriate conversion is
requested.

I agree that having the RAW field be an integer is a limitation.  For
example, I might want to read a voltage from a digital multimeter, which
returns a floating point number, but then have that number converted to
some other units, for example pressure, by the ai record conversion
routine.  As it stands I think device support would have to do that
conversion directly, it could not write into the RVAL field and ask the
record to do the conversion.

Mark


Replies:
Re: aiRecord, RVAL vs. VAL Brian McAllister

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