Sensitron SMART3G-GrI, Инструкция по эксплуатации

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ENGLISH
Pag. 20
1. Introduction
These security instructions refer to the installation, use and maintenance of SMART3G-GrI
gas detectors series (identification code ST/…/.), for use in areas with potentially explosive
atmospheres classified as zone 1 or zone 2, in mine, tunnel and underground applications
(Group I).
1.1 General description
Gas detectors series SMART3G-GrI are devices complete with sensor, housing and interface
circuit, that can be connected to both analog and addressable control panels as well as with
the control panel MU+.
SMART3G-GrI are used to detect the presence of combustible substances (mainly methane
% LFL), oxygen or carbon monoxide in an atmosphere consisting mainly of air with the pos-
sible presence of grisou.
Some models are supplied with catalytic sensor, others with infrared sensor or electrochemi-
cal cell. The industrial grade catalytic sensor (pellistor) employed for the detection of flam-
mable compounds offers a great precision and selectivity with most of the explosive gases,
thus avoiding false alarms.
Infrared sensors are immune to poisoning produced by certain substances that inhibit and
damage catalytic sensors. This allows you to add reliability and durability, allowing the use of
detectors even in places where the pellistors cannot guarantee optimal functionality.
The electrochemical cell, extremely precise and reliable, has excellent performance in de-
tecting gas at low concentrations, which is why it is suitable for applications in environments
where toxic gases are present.
SMART3G-GrI gas detectors can be equipped with optional boards, such as a 1 or 3 relay
board or a RS485 communication board. The display version is equipped with a display bo-
ard which integrates 3 relays; in this case it won’t be possible to connect the 3 relay board
because the connector is the same.
To check the detector’s calibration use the display board with hall effect sensors or the cali-
bration keypad STS/CKD+, available from november 2020.
To protect and increase the stability and accuracy of the gas detector, the microprocessor
present on the internal electric circuit board, is programmed with the following software
algorithms:
³
Self diagnostic procedure to control the detector main operational parts, both har-
dware and sensing element.
³
Zero point tracking to maintain the zero parameter of the sensor apart from possible
drifts due to thermal or physical variations of the sensor.
³
Digital filter employed in the digital analysis of the analogue values sampled. It is de-