Physitemp Instruments CT-3 - Manual (Page 2)

2
CT-3 OPERATING MANUAL
1.0 GENERAL
DESCRIPTION
1.1
The CT-3 is a simple device that simulates thermocouple signals so that the accuracy of
a thermocouple thermometer can be checked instantly, without waterbaths.
1.2
The regular CT-3 is designed for use with type T thermocouple thermometers and has
fixed electrical signals corresponding to five temperatures: 0.0 , 15.0 , 37.0 , 45.0  and
50.0 C. It is possible to order CT-3 with other settings. Consult Physitemp Applications
Department for further details.
1.3
IMPORTANT, PLEASE NOTE: This instrument is only designed to check calibration
accuracy – it is not designed to be used to calibrate the instrument under test. Consult
Physitemp Service Department for further details.
2.0 INTIAL
INSTALLATION
2.1
Connect one end of the thermocouple extension lead to the recessed socket on the left
end panel of the CT-3. Check the polarity – the connector will fit in one way only. Connect
the other end to the probe input socket on the thermocouple thermometer to be tested. If the
thermocouple thermometer under test is a multiple input device, be sure that the correct input is
selected.
2.2
Press the red BATT CHECK button. If the green LED lights, the instrument is ready
for operation. If the LED does not light, batteries may need reconnection or replacement.
See section 4.0 for details.
3.0 OPERATING
INSTRUCTIONS
3.1
All measurements should be taken in a room at a relatively constant ambient
temperature (within 2C in the ambient range of 15 -35C.) The CT-3 should be allowed to
stabilize for at least 30 minutes if moved from one room to another.
3.2
After connecting the lead to the thermocouple thermometer, allow ten minutes for all
spurious thermocouple voltages to stabilize. These spurious voltages can be generated by
moving the CT-3 from one part of the same room to another or by touching the thermocouple
connector with warm or cold hands.
3.3
Note the correction factor on the underside of the CT-3. (The correction factor is
indicated on the underside of the instrument on the calibration sticker) Turn on the
thermocouple thermometer. Add the appropriate correction factor to the mercury thermometer
reading and compare this figure to the displayed temperature on the thermocouple
thermometer. If they agree to within the accuracy specifications of the thermocouple