11 Definition of Terms
11 Definition of Terms
- 47 -
11
Definition of Terms
Catalytic
combustion type
This is a principle of the sensor installed in the Type GP.
See "10-2. Detection principle" for details.
Initial clear
Output from the detector head fluctuates for a while after turning on the power.
This is a function to prevent triggering alarm during that time.
Full scale
Maximum value of the detection range.
%LEL
A unit which the lower explosive limit (LEL) of the combustible gas to be detected is
set to 100.
ppm
A concentration unit that means part per million of the combustible gas to be
detected.
Calibration
Adjusts the readings to the calibration gas concentration value by using the
calibration gas.
Zero suppression
A function to cut off the specific drifting that the sensor has.
Alarm delay time
A function which temporarily suspends activation to prevent a false alarm caused
by noise from its outside.
INHIBIT
The gas detection function is temporarily suspended during maintenance, etc. of
the detector.
This is also called "point skip", which has the same function.
IEC 61508
International standard on functioning safety of electrical, electronics and
programmable electronic in process industry established by IEC (International
Electrotechnical Commission)
Functional safety
Ensuring levels of safety that it acceptable that implements functional
device(functions that safety are secured) to the final products.
SIL
Measure that safe performance of indicator and systems in IEC61508.
