RE: Equipment Availability

["David Dudley" <DavidDu@cctexas.com>]

I see that TIS-4000 had almost all the drivers I'm looking for.  Would it be easier to port one of those drivers to the newer EPICS, or easier to take an existing driver and gut the internals to make it work with the hardware I have?

David Dudley

>>> Steven Hartman <hartman@fel.duke.edu> 09/05/06 4:12 PM >>>
On Tue, 5 Sep 2006, David Dudley wrote:

> I spent 3 or 4 days looking for I/O cards for VME or compactPCI, and
> have discovered that there are very few industrial I/O cards offered.
> Industrial cards are usually optically isolated, and directly handle
> 110VAC on inputs and outputs, and the analogs all handle 4-10ma current
> loops without converters.  You can use a simple resistor for converting
> an input (technically considered a 'kludge' by most in industrial
> working circles), but analog outputs generally take special adapters to
> convert from voltage to current.

I would second Bob Dalesio's recommendation to try and get EPICS working
with your existing I/O first. But there are some VME based modules which
are better suited for an industrial environment. VMIC has some
opto-isolated digital I/O (BI and BO) at 110 VAC, and their 4120 is a
12-bit DAC with 0-20 mA or 4-20 mA outputs. For analog inputs, I have used
a resistor across my input and don't consider it too bad of kludge, but
there are some ADCs which will take a 4-20 mA input.

In terms of numbers, most I/O channels in an accelerator controls system
are rather slow (most between 1 and 10 Hz here). The high sampling-rate
applications just get all of the attention <g>.

-- 
Steve Hartman
hartman@fel.duke.edu || 919-660-2650
Duke Free Electron Laser Laboratory


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