General Tools and Instruments CDM7722 - Manual (Page 10)

9
CO CALIBRATION
2
CAUTION:
1. Do not calibrate the meter in the
air with unknown CO level.
2
Otherwise, it will be taken as 400
ppm and leads to inaccurate
measurements.
2. When operating the meter in the
close indoor areas that are not
ventilating,
be sure
to disable the ABC function to
prevent incorrect calibration.
such as hospitals or
offices with windows shut,
The meter is calibrated at standard
400ppm CO concentration in factory.
2
It’s suggested to do either ABC or
manual calibration regularly to maintain
good accuracy.
Note:
When the accuracy becomes a concern
after a long time usage or other special
conditions, return to dealers for standard
calibration.
Fig. 14 Fig. 15
CO
2 CO
2
Press and it goes into P4.
1
with
blinking “dis” default (Fig.14) on the
lower left display. To enable the ABC
function, press or and “En” blinks
for choice(Fig. 15). After the preferred
selection is done, press to save the
setting or without saving and return
to P4.
0
SET SET
DP/WB
M / X N
AVG
SET SET
CAL
ESC
CAL
ESC