Lightwave Communications LDT-5525 manual LM335 Sensor Calibration

MAINTENANCE AND TR OUBLESHOOTING

Calibration Adjustments

LM335 Sensor Calibration

C H A P T E R 3

The following procedure is for calibrating the LM335 sensor measurement so that the temperature measurement will be as accurate as possible. This procedure calibrates the voltage measurement of the LM335. This procedure does not calibrate C1 and C2. For information on calibrating the LM335 sensor, see Appendix C.

Calibration may be aborted by pressing the OUTPUT switch.

aSet the SENSOR SELECT switch (back panel) to the LM335 position. Set C1 to 0.00, C2 to 1.00.

bConnect a precision 4 KΩ metal film resistor and a precision voltmeter in parallel at the sensor input of the LDT-5525 Temperature Controller (pins 7 and 8).

cEnter the sensor calibration mode by pushing the MODE and SENSOR CAL switches at the same time. After this, the display will indicate sensor reference voltage in mV. Wait for three seconds for the measurement to settle.

dPress and hold in the ENBL switch and turn the ADJUST knob until the display indicates the same voltage as shown on the precision voltmeter multiplied by 10. For example, if the voltage across the resistor is 1.9871 Volts, turn the ADJUST knob until the display reads 19.87.

eRelease the ENBL switch and wait for the VIEW SET indicator (LED) to be unlit. Replace the 4 KΩ resistor with a 10 KΩmetal film resistor. After three seconds, repeat Step d with the 10 K* resistor. Ten seconds after the ENBL switch is released, the LDT-5525 Temperature Controller will store the calibration data in non-volatile memory.

fPress the DISPLAY switch three times to rotate the display back to the SENSOR mode. After calibration, I LIMIT will be automatically set to 4.00 Amps. Reset the I LIMIT to the desired value.

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