Owner's Manual

GDX-350 Sensor Transmitter
P/N: 5600-9001 Rev 2 29
4. OPERATING INSTRUCTIONS
4.1. Routine Sensor Calibrations
Calibration is the most important function for ensuring correct operation of the GDX-350. The CAL MODE
(flow chart shown in Figure 4-2) is designed to make calibration quick, easy and error free.
The 4-20 mA output indicates CAL MODE by transmitting 1.5 mA for 3-wire installations. It then transmits
4 mA during the subsequent CAL PURGE delay to prevent external alarms during calibration. Local
GDX-350 alarm relays (if equipped) are inhibited during CAL MODE. CAL MODE automatically exits if no
keystrokes are detected after 5 minutes.
Figure 4-1: Calibration Gas Input