INFICON Sensistor ISH2000 Hydrogen Leak Detector - Manual (Page 26)

Hydrogen leak detector Sensistor ISH2000 - Operating Manual
26 OM-Sensistor ISH2000-EN-201304
EN
Calibration can be performed with:
• a known hydrogen concentration
• a known flow leak
The following characters can be used: Upper and lower case Roman letters, the
numbers ь,
ь, Е, Д,Ц, е,д,ц,%,/,(,),and - (dash).
Note: The space (““) is not supported. The leak rate unit string will be cut short at
the first space found. See “Engineering format” on page 23.
Leak Gas
Leak Gas is the gas the Calibration Leak is defined to.
Calibration Time
The Calibration Time decides how long time the detector looks for a Calibration
signal before giving up. If the calibration is set to, for example, 6 seconds the
detector will record the maximum signal during 6 seconds after that the operator
(or external hardware) orders a calibration.
It is very important that all delays in gas exposure as well as reaction time of sensor
are taken into consideration when setting the calibration time. Calibration will not
be correct if the maximum signal comes after that the calibration time has
terminated.
This is also the timeout of the Calibration line in an APC program.
Interval
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.
In the menu Calibration/Interval there is a setting where it is possible to set a
reminder to calibrate the instrument. The interval can be set between 1 min to over
100 days. When it is time to calibrate, the instrument will signal with the text
Calibrate! in the display together with sound. If the interval time is set to 0, the
reminder function is switched off.
Function Calibration Interval can be used to remind the operator to perform a
calibration.