Chapter 6 Calibration
Page 6-1
6.1 Introduction
This chapter includes the procedures to calibrate the Analog-to-Digital Converter (ADC) circuit board and the RTD
current source. The actual calibration constants are automatically stored in Flash Memory on the Analog-to-Digital
Converter boards.
WARNING:
Do not attempt to perform calibration unless you are fully prepared to do so. Incorrect
procedures can destroy factory calibration. Read this entire chapter before attempting to
calibrate the unit.
NOTE:
Allow the Recorder to warm up and stabilize before attempting calibration. A warm up time of 15 minutes
at room temperature is recommended.
6.1.1 Routine Calibration
Routine calibration should be performed to maintain the accuracy of the instrument. The following items must
be performed for a routine calibration:
•
Zero Calibrate all channels
•
Calibrate the ADC Scales
•
RTD Current
6.1.2 Calibration Equipment
The following equipment items are necessary to calibrate the instrument:
•
One precision voltage source (accurate to ± 5 microvolts) adjustable from 10 microvolts to 25 Volts
•
One precision resistor 250 ohms 0.05% - Required for calibrating RTD
6.2 Zero Calibration
Before the Scales or RTD current are calibrated, a Zero Calibration must be done. A Zero Calibration must be done
when new channels are installed into the ADC board.
To perform a Zero Calibration:
Insert a jumper onto all channels (see the Unused Input diagram in Figure 2-7). From the Hidden menu use the
UP
(
↑↑↑↑↑
)
or
DOWN (
↓↓↓↓↓
)
button to highlight
ADC Control
and then press the
ENTER
button. The only available option is
Cal Adc
so just press the
ENTER
button. Use the
UP (
↑↑↑↑↑
)
or
DOWN (
↓↓↓↓↓
)
button to highlight
Cal scales
and press
the
ENTER
button. Use the
UP (
↑↑↑↑↑
)
or
DOWN (
↓↓↓↓↓
)
button to select
Zero cal.
and press the
ENTER
button. A pop
window with “SHORT ALL INPUTS”. Press the
OK?
button. A pop window will show the readings from channel 1.
Press the
CAL.
button. You will be prompted with “Are You Sure?”. Press the
CAL.
button again to calibrate the
channel or the press the
NO
button to cancel.
NOTE:
Zero calibration must be done to all channels. Only the readings from channel 1 will be shown.
Once the Zero Calibration is done, remove the jumpers and press the
EXIT
button three times to get back to the
Hidden menu.
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