Atest Gaz Sigma SmArt, User Manual

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Instructions for removing the lock of a detector
with a catalytic sensor
Detectors using a catalytic sensor (more details concerning the sensor – see Appendix PU-Z-054-ENG) are
equipped with a system protecting against its damage caused by a gas concentration exceeding the measuring
range of the sensor and before entering non-monotonic part of the catalytic sensor characteristics. In the case of
occurrence of such a situation, the detector is switched into the lock state. In this state, the detector saves the
last value of gas concentration and switches it off to protect the sensor and prevent false indications.
The lock state is signalled on the detector's display and on all devices showing the detector status (e. g. control
units). When the lock detector status occurs, the level of gas concentration in the place of the detector operation
must be measured with the use of another measuring device. In a situation when the concentration level drops
to the value within the measuring range of the sensor, the operator may proceed to removing the lock – see
illustration 1. If the lock is turned off, when the gas concentration in the place of the detector operation is
beyond the measuring range of the sensor, a permanent sensor damage or a false reading of the concentration
can occur, as a result of the non-monotonic characteristics of the sensor.
When the detector is in the inhibit state and the gas overload condition occurs, the detector will also enter the
lock mode and it will be visible after the inhibit mode is deactivated.
The method of executing the "Remove the lock" command can be found in the documentation of the control
unit that controls the detector. Turning off the power of the detector automatically disables the lock.
Removing the lock on a detector which is in the conditions of concentration above the
measuring range can damage the sensor.
Removing the lock on a detector which is in the conditions of concentration over the
measuring range can cause its false indication (due to the non-monotonic characteristics of
the sensor).
Figure 1: Operation of lock on /off detector
Atest-Gaz A. M. Pachole sp. j.
ul. Spokojna 3, 44-109 Gliwice, Poland
VAT No.: PL 9691433231
tel.: +48 32 238 87 94
fax: +48 32 234 92 71
e-mail: contact@atestgaz.pl
p. 1/1 Appendix: PU-Z-093-ENG R01
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Range
Time
Legend
Gas
concentration
Gas concentration
Wskazanie czujnika
Lock on Lock off
No possibility to lock on
Possibility to lock on
Heating