Metrohm 7010 TOC, User Manual

Page: 47 / 81

7010 TOC ANALYZER ­ USER MANUAL
47
4.3.1 ZEROGAS
Starts a zerogas cycle.
This value is typically lower than 200 ppm
The
ZEROGAS
value expressed as
CO2
ppm is automatically
stored in the analyzer database.
A
ZEROGAS
cycle starts automatically at the time and interval
programmed in the timing menu or by manually pressing for few
seconds the button
ZEROGAS
on the calibration page.
During a zerogas cycle the pumps and UV lamps are switched off.
In these conditions the carrier gas goes through all the fluidics to
reach the
NDIR
. The
CO2
concentration value expressed in ppm
detected by the infrared analyzer decreases so that after the
programmed delay time it will be stable and equal to the
CO2
generated by carrier gas only. This value is stored and shown as
ZEROGAS
.
A graphic of the trend of the ppm of
CO2
value detected by the
NDIR
is shown together with a counter of the seconds
programmed for the zerogas cycle, the value of ppm of
CO2
measured and the last zerogas value.
Refreshing frequently this value is extremely important because
the sodalime loses its capacity to adsorb
CO2
from ambient air.
If the
ZEROGAS
exceed a certain preset limit, the alarm “Zero too
high” will be activated and the analyzer will display this alarm
message.
To exit Zerogas simply press