Dräger Multi-PID 2, Руководство пользователя, Страница: 20 / 107

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Introduction
General Operation
The Multi-PID 2 is a microprocessor-controlled air monitor for measu-
ring the presence of photoionizable compounds in air at parts-per-mil-
lion levels. The block diagram in Figure 2 shows the main
components of the Multi-PID 2.
Figure 2 – Multi-PID 2 Block Diagram
The microprocessor controls the components of the instrument and
interprets and records the signal generated by the photoionization
detector (PID). Recorded data and setup information entered into the
microprocessor’s memory are retained when the Multi-PID 2 is turned
off.
A pump continuously pulls the air under test through the Multi-PID 2’s
PID. The Multi-PID 2 converts the concentration of photoionizable
compounds in the sample into an electrical signal. The microproces-
sor subtracts any background from the signal and divides this signal
by a sensitivity obtained by calibrating with a standard gas of known
concentration. This concentration appears on the Multi-PID 2’s dis-
play and, depending on the values entered through the Multi-PID 2’s
keypad, an alarm status may be displayed and an audio signal may be
heard.
The Multi-PID 2 can detect thousands of different types of airborne
gases and vapors and its response depends on the characteristics as
well as the concentration of each compound.
The Multi-PID 2 does not distinguish one type of compound from
another, but displays a number indicating the total concentration
of all photoionizable compounds in the sample.
Electrocal Connections Gas Connections
00623958_01_en.eps
Display and
I/O Connector
Microprocessor
Keypad
Photoionization
Detector
Inlet
Filter
Pump
Sample Out Sample In
Power
Supply