[Halld-controls] Type J Thermocouples in the CDC

[Joshua Ballard]

The Omega devices are $65 per channel (4 channels) - we'd need 3 of 
these devices plus 3 serial to EPICS interfaces (I don't know what these 
would be, or what they would cost).  And then we'd need to spend the 
money for you to program them.

If we went the Allen Bradley route, it would take 5 minutes to configure 
the modules and assign aliases to the hardware tags and they'd 
immediately be available to EPICS.  Additionally, the Allen Bradley 
stuff is made for industrial environments in which case our 
maintenance/repair costs would be next to nothing.

I tend to think the lifetime cost of the Allen Bradley solution is lower.


On 3/8/2012 6:09 PM, Hovanes Egiyan wrote:
> 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
>> _______________________________________________
>> Halld-controls mailing list
>> Halld-controls at jlab.org
>> https://mailman.jlab.org/mailman/listinfo/halld-controls
> _______________________________________________
> Halld-controls mailing list
> Halld-controls at jlab.org
> https://mailman.jlab.org/mailman/listinfo/halld-controls