Re: What hardware are you using for TC measurements?

[Mark Rivers via Tech-talk <tech-talk at aps.anl.gov>]

Hi Rich,

At our beamlines at the APS we use the following:

• Keithley 2001 and 2100 multimeters.  These have plugin cards that handle 10 or 20 thermocouples.  These use electro-mechanical relays for switching channels.  Surprisingly we have been using them for over 30 years, switching channels at 1Hz and have never had a relay failure.  Devices like this are nice because they are not limited to thermocouples, they can also measure current, resistance, etc.  My EPICS software lets you read different types of values on a per-channel basis.
• Measurement Computing E-TC.  These handle 8 thermocouples and have been very reliable.
• Measurement Computing USB-TEMP and USB-TEMP-AI.  We bought these because they can handle not only thermocouples but also RTDs and semiconductor sensors.  We don't use them much.
• Measurement Computing TC-32.  I wrote the driver for this and tested it.  We don't use it on our beamlines, but I believe that other beamlines at the APS are using them.
• LabJack T7-PRO and T8.  These handle 7 or 8 thermocouples.  They can read temperatures much faster (> 100 Hz) than any of the other devices above.  They also have analog outputs, so they are convenient for temperature control using an external power supply and the EPICS epid record for feedback.  With the other devices list above a separate analog output device is needed for temperature control with analog controlled power supplies.  With digitally controlled power supplies of course that is not needed.

All of the devices listed above meet your 4 requirements except that only the LabJack devices can run at 10 Hz, the others are limited to a few Hz depending on how many channels are in use.

Mark

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From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of Evans, Richard K. (GRC-H000) via Tech-talk <tech-talk at aps.anl.gov>
Sent: Wednesday, July 22, 2026 8:29 AM
To: tech-talk at aps.anl.gov <tech-talk at aps.anl.gov>
Subject: What hardware are you using for TC measurements?

 

Hello,

If you are making TC/thermocouple measurements in EPICS, please take a moment and let me know:
- What hardware you are using?
- What device support module you are using?
- Would you use it again on a new system?

We are looking for hardware options for thermocouple measurement devices that already have full EPICS device support and would be easy to use in a new system. Our goal is to select a device that ensures that we don't have to do any device support software development for it.   I am currently considering Digilent TC devices as supported by the EPICS measComp module (github.com/epics-modules/measComp), but I would like to see what else is out there.

For the purpose of this inquiry, the key requirements for the TC devices we need are:
* Software configurable for all TC types
* Reference junction temperature compensated
* Able to run continuously for > 90 days without requiring any recalibrations or disruptive services of corrections
* Able to be synchronized with other devices clocking at the same rate (say 0.1 Hz to 10 Hz)

Eager to hear about what everyone is using and what people recommend.

Thanks!
/Rich

Richard Evans, Information Systems
NASA's Neil A. Armstrong Test Facility
6100 Columbus Ave., Sandusky, Ohio 44870
mailto: richard.k.evans at nasa.gov