Calibration : Fluke 52 II Series thermometer

[TiN]

I'm back home, and what we have here for today?



Guesses? 

[TiN]

Fluke service manual with calibration procedure.
Fluke recommends 5700A calibrator, but we will use poor-man DC standard, EDC MV106.

Initial inspection, "before calibration" state.
On right side - ADC calibration fixture (two-copper terminal jack made from two thermocouple T jacks).



Cal sticker is tampered.



-82°C with tested K-type thermocouple hanging in +25C room temp ain't right.



Closeup for connector used for voltage source (EDC MV106 DC standard calibrated to Keithley 2001 with Tek cal 5.FEB.2014) connection to Fluke 52-2 inputs.
I used copper wire from UTP LAN cable.

0.0000v set - meter shows 20-30C...



Calibration A-D convertor by providing 80.0000mV and -8.00000mV to inputs.



-8.00000mV read as -7996.9 uV, which is in range for calibration requirements of –7995.0 to –8005.0.

Calibration reference point:



REF point offset is 3.8C.



After corrected offset:



"After calibration" Performance test values (K-Type Thermocouple) with icebath.
Channel 1 on left, channel 2 on right:

1. 0.0000 mVDC / 0.0 °C



2. 0.9193 mVDC / 23.0 °C



3. -5.7297 mVDC / -190.0 °C



4. 40.8853 mVDC / 990.0 °C



5. 48.8382 mVDC / 1200 °C



Same K-type probe reads correct +25.6°C now.



Thanks for watching



P.S.

Used gear:

Calibrated Keithley 2001 Multimeter (5.FEB.2014)
Keithley 2002 Multimeter (10.APR.2007)
Calibrated EDC MV106 DC Voltage standard +-30ppm/°C (8.FEB.2014)
Calibrated Keithley 2400 Sourcemeter (14.JAN.2014)