Siemens ULTRAMAT 23, Руководство пользователя, Страница: 161 / 244

ULTRAMAT 23
Manual, 3/2016, A5E37100388-003
161
Application note
9
9.1 H2S sensor with 'small' measuring range
This section reflects the experiences gained with operation of a sensor for a measuring
range of 5/50 vpm H
2
S.
Packaging
The transport packaging is not gas-tight. To prevent drying-out of the sensor and the
possibility of malfunctions, the sensor may only be stored for a period up to 3 months.
Storage and transport
Storage at an excessively high humidity (tropics, several months) results in swelling of the
electrolyte which could damage the electrolyte vessel.
As a rule of thumb: The sensor can be used for 12 months following manufacture and
storage.
Battery
The ULTRAMAT 23 must be operated continuously since the H
2
S sensor has its own battery
whose voltage is retained through operation of the ULTRAMAT 23.
With the analyzer switched off, the power supply to the sensor is from its own battery. The
resulting discharging of the battery impairs the sensor functionality and results in zero and
span drifts as well as increased signal noise This malfunction may last for 2 days or longer.
Materials used in the sample gas path
As a result of its polarity and good solubility in water, H
2
S accumulates on various materials.
These adsorption and desorption effects lead to increases in the response times. Therefore,
the inlet piping for the sample gas should be made of PTFE. Other materials should only be
used for short gas lines.
Ambient temperature
The influence of ambient temperature on the sensor is 3%/10 °C, referred to the full-scale
value; this corresponds to 1.5 vpm/10 °C.