Experimental Physics and
Industrial Control System

Korhonen Timo <[email protected]> · Fri, 28 Apr 2000 15:12:13 +0200 (MEST)

Hi all,

I wanted to use the aao (array analog output) record and noticed a
problem: when I put an array to the channel that is shorter than
the original NELM value, the NELM gets set to the number of put
elements.
A search in the tech-talk archive resulted in the following hit
(from April, 1996!):

>From: "Eric Bjorklund, NPSM" <[email protected]>
>Date: Thu, 11 Apr 1996 12:19:54 -0600 (MDT)
>Subject: Possible Problem with aao Record
>Message-Id: <[email protected]>
>
>
> We have discovered what may be possible bug with the aao record.  The
> problem appears to be in the "put_array_info" routine, which stores the
> number of points to write in the NELM field of the record.  The problem
> with this that if you write less than NELM points to the aao record,
> any further connections to this record get the new, lower, value of NELM
> (through "cvt_dbaddr" or "get_array_info") and are no longer able to
> write as many points as the record originally specified.
>
> My questions are:
>
> o Shouldn't "put_array_info" be updating the NORD field instead of the
>   NELM field? (if so, it means we should probably change the code in
>   devAaoCamac.c as well).
>
> o What is the correct value, NELM (the capacity of the record) or NORD
>   (the number of points actually written) to return from "cvt_dbaddr"
>   and "get_array_info"?
>
> o (and, BTW...  shouldn't SIOL be defined as an OUTLINK on an aao
>   record?)
>
>                                        Eric Bjorklund
>                                        AOT-6 (LANSCE Operations)
>                                        LANL ([email protected])

I tried the changes that Eric proposes and then the aao seemed to work
as I expected.

Have I missed something, is there a real reason for that behaviour or
have the fixes been left out from the distribution (I am using 3.13.2) 
by mistake?

Timo

Timo Korhonen  PSI (Paul Scherrer Institut), SLS 
               CH-5232 Villigen PSI 
               tel + 41- 56 3103262  fax + 41 - 56 310 3151 
e-mail:	       [email protected]

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System