RE: multi-channel analog i/p

[<nick.rees@diamond.ac.uk>]

Hi Paul,

 

This is basically a software triggered analogue read. Often ai’s have hardware triggers to tell the ADC to sample – frequently across many channels as you propose. The triggers have to be supported by the driver layer, of course. A software trigger (as you propose) would typically be represented by a binary output record, which would cause the driver to trigger sampling, and the values would be fed back to the Ai records by having them I/O Intr scanned.

 

However, all this needs proper support in the driver. It is best to start off with a board with a driver that supports all this, but otherwise you need to write a suitable driver for your board. In the VME world, we use the Hytec 8401 for this sort of job – the software manual is on the Hytec website: http://www.hytec-electronics.co.uk/PDF/Hytec%20EPICS%20Device%20Driver%20User%20Manual.pdf.

 

There is also some areaDetector work going on to generate a 2-D dataset from multiple triggers across many channels – that may be interesting depending on your use case.

 

Cheers,

 

Nick Rees

Principal Software Engineer           Phone: +44 (0)1235-778430

Diamond Light Source                  Fax:   +44 (0)1235-446713

 

From: tech-talk-bounces@aps.anl.gov [mailto:tech-talk-bounces@aps.anl.gov] On Behalf Of Stephen Paul
Sent: 23 June 2015 06:37
To: tech-talk@aps.anl.gov
Subject: multi-channel analog i/p

 

Hi guys,

 

I have a 32-channel analog input board. I don't want to use 32 ai records reach reading directly from h/w.

 

Instead , I first want a record and its device support to read all the channels from the board in one go and then pass these values to individual 32 ai records for conversion.

 

Can anyone suggest what type of record I can use before ai record to achieve this ?

 

Thanks,

Stefen.

 

 

 

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