ILX Lightwave LDT-5525 User Manual page 43

IV. LM335 Sensor Calibration
1______ Set C1 to 0.00, C2 to 1.00.
2_______ Set the sensor select switch to "LM335" (-03-).
3_______ Connect the 5525 Sensor Test Fixture to the output connector. Set the 5525 Sensor Test Fixture to
SENSOR 3, Load 1.
4_______ Connect a voltmeter to the 5525 Sensor Test Fixture via the banana jacks. Measure the voltage. It
should be about 1.98 volts.
5_______ Hold down both the "MODE" and "CAL" buttons. This will put the 5525 into "Sensor Cal" mode.
6_______ Allow the sensor measurement circuit to settle, usually about 3 seconds.
7_______ Hold down the "ENBL" button and turn the knob until the display reads the voltage across the
calibrated sensor resistor, multiplied by 10.
8_______ Release "ENBL", wait for "VIEW SET" light to go out.
9_______ Set the 5525 Sensor Test Fixture "Load" switch to position 2.
10______ Measure the voltage. There should be about 3.6 volts across the sensor resistor.
11______ Hold down the "ENBL" button and turn the knob until the display reads the voltage across the sensor
resistor, multiplied by 10.
12______ Release the "ENBL" button.
13______ Wait for the automatic set point cal procedure to complete - about 10 seconds.
14______ Check
Press display button to rotate the display back around to "Sensor °C". Display should read about
85.0
Set the 5525 Sensor Test Fixture to the "Chk" position. Measure the voltage (V sense). Check that
the
within ±0.1 °C.
8
Calibration can be terminated at any time by pressing the "OUTPUT" button. This will stop cal; no constants will
be saved to EEPROM.
9
For example, if the voltage across the resistor is 1.9871 V, dial in 19.87.
10
It doesn't matter which value resistor is used first.
the
display reads
9
10
sensor
×
(Vsense
3-13
8
cal:
°C.
100) - 273.2,