Re: Hardware to for thermocouple readout

[Steve Lewis <SALewis@lbl.gov>]

At 5:24 PM -0500 2000/04/25, Porter, Rodney wrote:
>I need to monitor 24 thermocouples.  Can someone suggest EPICS supported
>hardware for this application.  


Our method of choice here is to hook them directly to Allen-Bradley
Flex-I/O modules which are deployed close to the sensors.  These 8-channel
units handle all known types, and have cold-junction compensation
and a calibration procedure.  The unit is model IT-8.

Three IT-8 units can be combined in a small DIN-rail stack. (And they can
be mixed with other units for handling pressure, flow, whatever, in a nicely
distributed manner.)  With adaptor and power supply (but not including
6008 scanner) using typical discounts, it would cost about $3700

They can connect to the IOC either directly to the 6008 scanner (we are
just finishing device support) or via any A-B series PLC (in which case
the generic PLC device support already works).

We much prefer this "raw sensor" approach here to the rack-mounted/
multiplexed/bells-and-whistles/RS-485-protocol-from-hell style of the
typical catalog instrument.  Your mileage may vary...

_____________________________________________________________________
Stephen A. Lewis                        | SALewis@LBL.gov
Mail Stop 71-259                        | http://www.lbl.gov/~salewis
Lawrence Berkeley National Laboratory   | Tel: +1.510.486.7702
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