INFICON Sensistor ISH2000P Hydrogen Leak Detector, Panel Model - Manual (Page 20)

Hydrogen leak detector Sensistor ISH2000 - Operating Instructions
18 OP-Sensistor ISH2000-EN-201203
EN
1.00E+00 = 1.00 x 10
0
= 1
1.25E-02 = 1.25 x 10
-2
= 0.0125
8.3 Change Test Mode
Choose the measuring method you will use in the menu Change Test Mode. There
are three different methods to choose:
• Analysis Mode
• Detection Mode
• Combined Mode
See Reference section for a description of the functions.
8.4 Calibration
Calibrate
The instrument must be calibrated by using the integral calibration function to
ensure it displays the correct values in
Analysis Mode/Combined Mode . After
calibration the instrument will show the correct measured values on the display. The
calibration parameters will be stored into the probe.
Calibration intervals
Calibration is a natural part of leak measurement and an important factor in quality
assurance. It is impossible to specify an exact requirement for the interval between
the calibrations because the applications for which the instrument is used can vary
considerably.
There will be some oxidation of the probe sensor, which reduces the sensitivity, if
the probe sensor:
• is not subjected to gas for a lengthy period or
• is exposed to a very small gas concentration (less than 10 PPM) with long
intervals between exposure.
If the instrument is subjected to a very large gas concentration over a long period, a
certain amount of insensitivity can occur directly afterwards. This saturation can
make it difficult to detect very small leaks. Therefore, make it a habit of removing
the probe from the measuring point as soon as the measured value is displayed. This
gives the detector an opportunity to recover.
Sensitivity too low for reject level
The Detector will warn if sensitivity of sensor is too low to safely detect a leak equal
to the set Reject Level limit. The warning can be ignored and calibration updated
and the CAL_CONF output will be set.
High signal! Check reference!
The Detector will warn if the calibration signal is unreasonably high. This can occur,
for example, if 5% tracer gas mix has been used instead of proper reference gas or if
the reference leak has an extra non-intentional leak. The warning can be ignored
and the calibration updated and the CAL_CONF output will be set.