GMI Oxygas 500, User Handbook Manual

Page: 35 / 80

23
Zeroing the PPM Range
A double press of Button Two zeroes the current range.
This should be carried out in fresh air and may take a few
minutes to reach the optimum zero stability. The display in
Figure 3.5 occurs if a large adjustment is needed to reach
the zero point.
Figure 3.5 Zeroing Range
Switching Off
A double press of Button One turns the instrument off
immediately.
The instrument switches off automatically after 30 minutes.
‘OFF’ is shown in the top right hand corner of the display.
Pressing any button cancels this automatic switch-off. The
instrument will then allow another 30 minutes of use.
This 30 minute period is set as a default.
The switch off time may be altered to any time between 1
and 1000 minutes
OPERATION