Getting Started; U Npacking A New Sensor; P Olarization; C Onnecting The Microsensor - UNISENSE HYDROGEN SENSOR User Manual

GETTING STARTED

u
npacking a new sensor
When receiving a new microsensor remove the shock-absorbing
grey plastic net .
p
olarization
The signal from the hydrogen sensor is generated in picoampere .
Therefore the hydrogen sensor must be connected to a polarizing
picoammeter (e .g . a Microsensor Monometer, a Microsensor Multi-
meter, or Field Microsensor Multimeter) .
Hydrogen sensors should be polarized at +1000 mV . The polariza-
tion voltage is set in the amplifier . For details on how to set and
check the polarization, consult the user manual of the picoamme-
ter to be used . If you are using a PA2000 amplifier, please check the
polarization voltage before connecting the sensor, since incorrect
polarization may destroy the sensor .
c
onnecting tHe microsensor
Connect the LEMO connector to the input terminal . The LEMO
connector contains connections for both internal reference elec-
trode and sensing anode .
p -
re polarization
Just after connecting the sensor, the signal will be very high and
unstable then drop rapidly over the first few minutes . After that
the signal will drop slowly for up to 1 hour . Therefore, a period
of polarization is necessary before you can use the sensor . This is
called the pre-polarization period .
The signal should stabilize at 0-50 picoampere (on the PA2000, the
sign will be negative since sensor is positively polarized) for
zero hydrogen concentration, depending on the specific sensor . If
the sensor is new or has not been operated for several days, it
10
WARNING
Do not remove the
seal and protective
plastic tube
before these steps
and calibration
are succesfully
completed.
WARNING
Incorrect
polarization may
destroy the sensor