Experimental Physics and
Industrial Control System

Steven M Beard <[email protected]> · Tue, 13 Jul 1999 17:33:22 +0100 (BST)

On Tue, 13 Jul 1999, Luedeke Andreas wrote:

> Hi all,
> I need a waveform output record with variable array length.
> A pretty common requirement I think, so I hope someone has already done
> it.
> I'm writing device/driver support for the SLS power supply controller.
> The controller can download arbitrary reference current waveforms
> which will be started at an external trigger.
> As I understand, the 'aao' record does not support modification of the
> NELM field, to tell device support how long the current array is.
> I could send the data-length through the first value of the array or
> through an extra longout record to the device support, but maybe someone
> 
> can tell me a more common way.
> Thanks in advance
> Andreas

The "general subroutine" (genSub) record can handle variable sized arrays. 
The genSub record is similar to the subroutine record (in that it executes
a user defined function) but allows multiple input fields and multiple
output fields. Any of these fields can be a variable sized array (for
example the size and type of input field A can be defined using fields NOA
and FTA, and the size and type of output field VALA can be defined using 
fields NOVA and FTVA).

You might be able to handle your waveforms using the genSub record. 
Alternately, you could take the code from the waveform output record and
the code from the genSub record and merge them together to make your own
waveform output record which handles variable sized arrays (unless someone
else has already done this...). 

Steven

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Steven Beard
UK Astronomy Technology Centre
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Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System