Physitemp Instruments CT-3 User Manual

OPERATING MANUAL

CT-3

TEMPERATURE STIMULATOR

CONTENTS

Section

1.0 GENERAL DESCRIPTION

2.0 INITIAL INSTALLATION

3.0 OPERATING INSTRUCTIONS

4.0 BATTERY REPLACEMENT

5.0 SPECIFICATIONS

6.0 CALIBRATION

7.0 WARRANTY AND SERVICE

APPENDIX: CENTIGRADE TO FAHRENHEIT
CONVERSION CHART

(W/SD/Operating Manuals/EB CT-3) rev 11/04

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

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thermometer under test, continue the calibration check. If they do not, the thermocouple
thermometer may require recalibration.

Note: ensure that the mercury thermometer is viewed perpendicular to the tip of the
mercury column to avoid parallax effects.

3.4 Press the grey ON ADJUST button on the CT-3. While holding down this button, turn
the ADJUST knob until the thermocouple thermometer displays 25.0 C (77.0  F)

3.5 Continue to hold down the grey button. Press in turn the 0.0 , 15.0 , 37.0 , 45.0 
and 50.0 C buttons. In each case, the thermocouple thermometer should display the
temperature selected to within 0.2 C. If the difference between the thermometer display and
the temperature selected is greater than 0.2 C, the thermocouple thermometer needs to be
recalibrated.

If you are using a Physitemp thermocouple thermometer and do not have calibration facilities,
the instrument can be returned to the factory for calibration.

4.0 BATTERY REPLACEMENT

4.1 CT-3 uses two EN90 1.5V alkaline cells.

4.2 Place the CT-3 on a flat surface and carefully remove the six screws, which secure the
top cover to the base. Remove the cover carefully. Note the thin wire running between the
thermometer block in the base and the circuit board in the top cover. TAKE EXTREME
CARE WHEN REMOVING THE TOP COVER AND ENSURE THAT THIS WIRE IS NOT
DISLOCATED OR DAMAGED.

4.3 Battery holder is on the underside of the circuit board. Note the orientation of the two
batteries, then remove and replace with new cells of the same type. Press red BATT. CHECK
to verify that the LED lights after new batteries are installed.

4.4 Re-assemble the top cover and base. Be sure that the wire is not caught between them.
Replace washers and screws.

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5.0 SPECIFICATIONS

Thermocouple Type: Type T, copper-constantan

Temperature Simulated: 0.0 , 15.0 , 25.0 , 37.0 , 45.0 , 50.0 C

Accuracy: Better than 0.1 C

Ambient Operating 15 to 35 C (Mercury-in-glass thermometer)
Temperature:

Power Supply: 2 “N” size alkaline cells, 1.5v each

Expected battery life: 200 hours continuous operation. 2 years intermittent

Low Battery warning: LED

Size: 11 3/16” L x 3 9/16”W x 2 3/8” H

Weight: 24 0z.

6.0 CALIBRATION

It is recommended that the CT-3 be returned to Physitemp on a 12 month basis for calibration
and re-certification to NIST standards

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7.0 WARRANTY AND SERVICE

7.1 WARRANTY

Phystiemp warrants this instrument to be free from defects in material or workmanship for 12
months from date of shipment. Repair or replacement will be made at no charge at the
discretion of Phystimep if the defect is not the result if misuse or abuse. Physitemp accepts no
consequential liability for delay in delivery, alleged faulty performance of the product or any
other cause.

7.2 SERVICE

For technical or applications information on this instrument call [phone].

In the event that the CT-3 is to be returned for service, please pack it with care and send it
prepaid to:

Service Department
Physitemp Instruments
154 Huron Avenue
Clifton, NJ 07013

Please include with instrument:

1. A note describing any problem encountered

2. the name and telephone number of a person we can contact

3. the complete return address for shipping

For your protection, please pack the item carefully and insure against possible damage or loss.
Physitemp will not be responsible for damage resulting from careless packaging.

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