Re: Scaling Database entries

[Andrew Johnson <anj@aps.anl.gov>]

Hi Dirk,

Dirk Zimoch wrote:
> In 3.13, there was no "SLOPE", and even now I cannot find any 3.14 
> Record Reference Manual which would explain the use of "SLOPE". 
> StreamDevice does not make a difference between "SLOPE" and "LINEAR" at 
> the moment.

True, SLOPE conversion was added in R3.14.  It is described in the Base 
Release Notes, but it should be documented elsewhere too.  Unfortunately 
the Record Reference Manual is so out of date that it's embarrasing, but 
APS does not have the manpower to update it, and only one person has 
volunteered to help work on the Wiki version (which is still only for 
R3.13).  I will make sure it's listed in appropriate places in the 
Application Developers Guide for R3.14.9 though.

> > StreamDevice should have some way for the author of a protocol file to 
> > specify what the device's raw range actually is for analog records, 
> > and it should perform the calculation of ESLO and EOFF from that raw 
> > range and the EGUL+EGUF pair.  
>
> I think, I will add that. This can easily be done with two variables in 
> the protocol file.

Great.  The axRecord.c files already set EOFF to EGUL for you, so the 
code in your special_linconv() routines only needs to do something like 
this, assuming that the raw data values range from 0 to rawRange:

    if (after && prec->linr == menuConvertLINEAR) {
        prec->eslo = (prec->eguf - prec->egul) / rawRange;
    }

- Andrew
--
There is considerable overlap between the intelligence of the smartest
bears and the dumbest tourists -- Yosemite National Park Ranger