C H A P T E R 3
MAINTENANC E AND TR OUBLESHOOTING
Calibration Adjustments
AD590 Sensor Calibration
The following procedure is for calibrating the AD590 sensor measurement so that the temperature measurement will be as accurate as possible. This procedure calibrates the current measurement of the AD590. This procedure does not calibrate C1 and C2. For information on calibrating the AD590 sensor, see Appendix C.
Calibration may be aborted by pressing the OUTPUT switch.
aSet the SENSOR SELECT switch (back panel) to the AD590 position. Set C1 to 0.00, C2 to 1.00.
bConnect a precision 20 KΩ metal film resistor and a precision ammeter in series at the sensor input of the
cEnter the sensor calibration mode by pushing the MODE and SENSOR CAL switches at the same time. After this, the TEC display will indicate sensor reference current in µA. 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 current as shown on the precision ammeter.
eRelease the ENBL and wait for the VIEW SET indicator (LED) to be unlit. Replace the 20 KΩ resistor with a 10 KΩ metal film resistor. Wait for three seconds, then repeat Step d using the 10 KΩ resistor.
Ten seconds after the ENBL switch is released, the
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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