DOD PS-7 - Manual (Page 4)

2-2 21Vol% Adjustment
(1) Set to maintenance mode (MNT1 or MNT2).
(2) Release the password lock. (Refer to 1-2 Releasing the Password Lock.)
(3) Press the SPAN switch.
(4) Let the calibration gas through.
(5) Use the UP/DOWN switch to adjust the concentration indication on the screen to that of the calibration
gas concentration.
(6) When the adjustment is completed, press the SPAN switch again. The SPAN indication in the bottom
right corner of the LCD screen will then disappear, and the 21vol% adjustment is complete.
(7) Remove the calibration gas and confirm that no alarm is displayed( ALARM 1 , ALARM 2 is not shown). Then,
restore to the normal mode by switching the maintenance switch to the center.
Pull back to open
Left: Maintenance 1 (MNT1)
Center: Normal mode
Right: Maintenance 2 (MNT2)
TROUBLE lamp(yellow）blinks.
MNT1 or MNT2 is displayed at the
bottom of the LCD screen.
The “__” indication and the concentration
value of the Oxygen blink alternately.
SPAN is displayed at bottom of the
LCD screen
SPAN switch
Oxygen sensor unit: COS-7