I acquired a Cambridge instruments surface pyrometer in mediocre condition. I had to clean the electrical connections. I also had to clean the stator
in the meter, and re-solder a wire. Now it works, the meter swings, I'll have to re-calibrate it, it's only reading 200 deg. when I have it on a 400
deg heat source. Does anyone have any information on these units? I am curious as to what sort of thermocouple (type j. type k? etc.) that it uses,
and any other info out there.watson.fawkes - 2-9-2011 at 05:29
Does anyone have any information on these units? I am curious as to what sort of thermocouple (type j. type k? etc.) that it uses, and any other info
out there.
You can determine the type of the thermocouple in the sensor with a sensitive voltmeter. Just put
the sensor on/in a known-temperature heat bath and measure the voltage. For a heat bath, you could first try boiling water. Get the voltage and then
look up what kind of thermocouple junction generates that voltage at that temperature. Use multiple heat baths to check the calibration curve. There
are low-melting alloys in a wide range of temperatures that would provide a reasonably inexpensive standard.
As to the instrument, you can check its calibration by a kind of inverse procedure. Just feed a known millivolt-level signal into the meter and see
what it reads. You'll need to obtain or construct such a signal source.magnus454 - 2-9-2011 at 07:58
That's a good one, I didn't think of that. I'll have to see if I can find a DC Millivolt meter today while I am out, maybe a microvolt as well. I
could easily use my power supply and some resistors as a voltage divider to generate a millivolt or microvolt signal to check the meter core. Thanks!magnus454 - 2-9-2011 at 19:00
I did more work on the stator in the meter, it's running much better now, and reading accurately. I used my WESTON pyrometer with a brand new TYype
"J" thermocouple and the iron frying pan again and they read in unison now.
