Temperature Sensor

The MPS 400 also includes an internal temperature sensor for the coolant, as well as supporting an external temperature sensor. I connected an Aquacomputer coolant sensor to the external header. I then measured both sensors relative to my reference Dallas DS18B20 “one-wire” sensor located in a home made housing. I tested a wide range of coolant temperature by letting the system self heat slowly by unpowering the radiator fans while the PC sat idle:

The external AquaComputer probe tracked my reference probe very well. However the internal sensor was not only slow but had a significant ~2.5C difference in temperature even when finally settled:

It can also be seen in these plots that there is some curious behaviour around 30C. The external probe jumps 1C suddenly while the internal probe jumps 0.6C. As I hadn’t figured out how to get AquaSuite to log data automatically for me yet, I had been taking data manually and wondered if I’d simply made a mistake somehow so I ran the experiment again and this time logged it:

It happens on both the rising and falling:

While many people don’t intend to have their coolant go over 30C, it’s worrying that there is such a spike which again could be contributed to a poor calibration.  AquaComputer have since found the bug in AquaSuite that was causing this and will be fixing it in the next release!

Finally if we plot the temperature step from data point to data point we can get a feel for how responsive and how noisy the sensors are:

If anything the AquaComputer external sensor is just as noisy and even a little more responsive than my reference probe.

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4 COMMENTS

  2. How would you recommend calibrating this sensor suite (flow, temps) in a system? Any specific tool? Should it be re-calibrated once in a while?

    • I just found out that my multimeter has a type k thermal probe (no idea what that means, though). Is that enough to calibrate the internal thermal sensor of the mps?

      • Hah well thermal probes themselves often need to be calibrated. Since that review was written AquaComputer fixed the bug with the non linearity, so it should be a lot better now. Unless you’re really testing stuff it’s probably good enough to be honest. If it’s not it’s probably easier to buy a 10$ probe and add it in the loop instead.

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