Ion Science SF6 P2 - Manual (Page 8)

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Operation
Auto-zero at startup
To precisely determine SF6 concentration, SF6 AREACHECK P2 requires a reference value representing
clean air. This reference value is taken and stored whenever the instrument is powered up or reset. You
should therefore make sure that power up takes place under clean air conditions.
A fresh reference value is also taken after manual reset via the key switch. Therefore, after each
manual reset, the instrument will temporarily only respond to SF6 concentrations exceeding the level
that was present at the time of manual reset. This will avoid the next measuring cycle to trigger an
undesired, new alarm. The reference value will auto-adapt to falling SF6 concentrations, so after once
meeting a clean air condition, SF6 AREACHECK P2 will automatically return to full sensitivity.
Since a reset is also performed when the instrument is taken into setup mode via the host computer
interface, the above also applies in this case.
After Power up or reset, the first measuring cycle starts immediately, beginning with the fan run time.
Measuring interval
Since SF6 AREACHECK P2 is designed to determine slowly changing concentrations, it samples the air
at a fixed time interval rather than measuring continuously. This feature minimizes the amount of air
per time that passes the instrument’s intake system, thus extending its service life.
Via the measuring time interval, it is possible to perfectly adapt the instrument to the actual
application. For monitoring generally unattended spaces, a long time interval should be selected, while
in the working area a shorter interval is suggested.
SF6 AREACHECK P2 comes with a factory set measuring interval of 30 minutes, which is the suggested
starting point for most applications.
Indicator lights
6 LEDs on the instrument’s front panel represent its state as follows:
Placement of LEDs:
RUN
This light acts as a life sign to confirm the SF6 AREACHECK P2 is
in operation. As long as no internal
error condition is met, it will blink at all times. During the actual SF6
measurement (normally, this phase
is very short), it will blink at a faster rate.
Should this lamp stop blinking, an internal error has occurred.
ALARM
This light will be permanently on if the last measuring cycle has determined a SF6 concentration above
the selected alarm threshold.
In case of an internal error state, it will blink quickly.
The instrument’s internal audible alarm works in parallel with this lamp.
500 / 1000 / 1500 / 2000 [ppm]
These 4 yellow lamps reflect the last sampling period’s result in terms of alarm levels as designated.
On instruments equipped with the optional oxygen sensor, these lights have the following additional
functions:
• The two leftmost LEDs (500+1000ppm) will blink when an oxygen concentration below the
lower alarm threshold of 16% is present.
• The two rightmost LEDs (1500+2000ppm) will blink when an oxygen concentration above
the upper alarm threshold of 25% is present.