[Halld-controls] Type J Thermocouples in the CDC

[Hovanes Egiyan]

I am not sure if it is the least expensive way, but I think it would
be the best to use Omega RS232/RS485 interface devices with their 
thermocouples.
The programming of the serial for their devices for monitoring can be 
pretty easy;
I have not done it myself, but Krister from Hall B told  me that those 
he has are pretty
simple modules.

http://www.omega.com/DAS/pdf/D5000.pdf

Hovanes.


On 03/08/2012 04:39 PM, Joshua Ballard wrote:
> Hello,
>
> CMU plans to purchase 10, Type J thermocouples for the CDC.  I was asked
> to determine the best way to get the signals into the PLC and EPICS.
>
> Option 1:  ControlLogix thermocouple module.  The 1756-IT6I2 is a 6
> channel, Cold Junction Compensated (CJC) thermocouple input module.  The
> price per channel is $256.  In this case, the thermocouple leads would
> need to be routed from the CDC all the way over to the solenoid controls
> rack.  I believe thermocouple wire and connectors are "cheap", so this
> shouldn't be a problem.
>
> Option 2:  Point I/O thermocouple module.  The 1734-IT2I is a 2 channel,
> CJC thermocouple input module.  The price per channel is $161.   We
> currently have a Point I/O "chassis" installed in the solenoid controls
> rack and, again, we'd have to run thermocouple wire from the CDC to the
> solenoid controls rack.  That is, unless we anticipate additional
> thermocouple channels for the other detectors, in which case it may be
> advantageous to buy another "chassis" and install it closer to the magnet.
>
> The only reason to bring the thermocouples into the PLC is to get the
> values into EPICS.  The cost per channel for the Point I/O system seems
> comparable to Omega thermocouple controllers AND the PLC and EPICS
> programming would be minimal.
>
> So, unless somebody knows a better way to get thermocouple data into
> EPICS, my recommendation is that we use Point I/O.
>
> Josh
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