Hampshire Controls Corp.
Revision 1.2
Temperature Transmitter Operating Instruction
Page 18 of 21
©2014
Two-Point Calibration (Offset & Slope)
If Two-Point Calibration (2Pt) has been selected, the LCD may display either the current
temperature or the current value of the A/D in hexadecimal (hex) format. The display will
update every half second. To toggle between temperature and hex tap the MUTE/CAL button.
An example of both readouts is shown below.
Temperature display is easily noted by the decimal point.
Hexadecimal display may contain the numbers 0-9 and
the letters A-F.
During Two-Point Calibration you can also activate the ±0.1°C hysteresis that is used during
normal operation to stabilize the temperature readout. Hysteresis is indicated by the tilde symbol
on the display.
For field calibration, select the temperature readout and turn off hysteresis.
Now immerse the probe into a water bath at 0°C. Verify the water bath temperature using a
calibrated thermometer. Let the Temperature Transmitter temperature reading stabilize. The
decimal digit may flicker ±0.1°C. When you are satisfied that the reading on the Temperature
Transmitter has stabilized, press-and-hold the MUTE/CAL button until you hear a short beep,
then release the button. You have now set the zero-degree offset.
The readout should now display
±0.1°C.
Next, immerse the probe in a 40°C water bath. Verify the water bath temperature using a
calibrated thermometer. Let the Temperature Transmitter temperature reading stabilize. The
decimal digit may flicker ±0.1°C. When you are satisfied that the reading on the Temperature
Transmitter has stabilized, press-and-hold the DISP/PROG button until you hear a short beep,
then release the button. You have now set the forty-degree point.
The readout should now display
±0.1°C.
Return the probe to the 0°C water bath and verify the reading is still acceptable. Tap the RESET
button to return the Temperature Transmitter to normal operation.
If the STATUS LED starts to flash red
at any time during the calibration, then the
Temperature Transmitter requires a factory recalibration. Please contact Hampshire Controls
Corp. to arrange for recalibration. Tap the RESET button to exit the Calibration Mode.
