Operating instructions

AMC-DTR Sensor Transmitter User Manual
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6 OPERATING INSTRUCTIONS
6.1 Routine Sensor Calibrations
Calibration is the most important function for insuring correct operation of the AMC-DTR. The
CAL MODE (flow chart shown in Figure 17) is designed to make calibration quick, easy and
error free. A successful ZERO and SPAN calibration requires only four keystrokes. The 4-
20mA output transmits 3mA during CAL MODE and 4mA during the subsequent CAL PURGE
delay to prevent external alarms during calibration. Local AMC-DTR alarm relays (if equipped)
are inhibited during CAL MODE. CAL MODE automatically exits if no keystrokes are detected
after 5 minutes.
Follow these AMC-DTR calibration guidelines:
• Calibration accuracy is only as good as the calibration gas accuracy.
• Do not use a gas cylinder beyond its expiration date.
• Calibrate a new sensor before use.
• Allow the sensor to stabilize before starting calibration (approximately 5 minutes).
• Calibrate on a regular schedule. (AMC recommends once every 3 months, depending on
use and sensor exposure to poisons and contaminants.)
• Calibrate only in a clean atmosphere, which is free of background gas.
Figure 16: Calibration Gas Input