INFICON Sensistor ISH2000P Hydrogen Leak Detector, Panel Model - Manual (Page 25)

Hydrogen leak detector Sensistor ISH2000 - Operating Instructions
OP-Sensistor ISH2000-EN-201203 23
EN
background concentration will be detected. However, if the concentration remains
constant it will be gradually cancelled out over a period of several minutes.
For example, if the background concentration for some reason should suddenly rise
to 10 ppm H
2
, then the detector will give a corresponding signal which will very
slowly decline to zero. If you thereafter expose the probe to a leak which gives rise
to another 10 ppm H
2
, then the detector will give essentially the same signal as if
there were no background concentration.
Sensitivity
Sensitivity of audio signal and signal bar in Detection Mode .
Note: This does not affect the Analysis Mode .
Auto Range
Set this parameter to ON for auto ranging of sensitivity in Detection Mode . Sensitivity
will decrease two steps if the signal reaches full scale. Sensitivity is restored to
selected
Sensitivity (See “To locate leaks” on page 22) when signal returns to zero.
Direct Sensitivity Adjustment
Setting this parameter to OFF will remove the sensitivity adjustment from the
Detection Mode display. Sensitivity can still be adjusted in the Sensitivity Settings menu
after entering password (if set).
Note: The sensitivity setting only affects the Detection Mode .
Audio Threshold
Makes it possible to lower the sound to a set level in Detection Mode. The level is in
% of full Detection bar.
Reject Indicator
Makes it possible to show (not shown) the indication Reject in Detection Mode.
Audio Ready Pulse
This sets the standby sound to a silent or or pulsating tone.
8.6 Analysis mode
In Analysis Mode the measured value is displayed in figures. The default unit is in PPM
but it is possible to choose other units, See “Default parameters” on page 40.
To analyse leaks
The Analysis mode is used for measuring the size of a leak (or the concentration of a
gas sample). To be able to do this measurement and obtain correct values, the
instrument must first be calibrated using the calibration function.
In the Analysis mode the detector determines the gas concentration from the
change, as the probe goes from being exposed to background to being exposed to a
certain gas concentration. The detector does not continuously monitor the gas
concentration but takes just one reading instead. Another suitable alternative name
for this mode could be Sampling Mode. It is important to keep this in mind when
using the detector in this mode.