1. GENERAL PURPOUSE
The
MDP-4.(-,A,B,Z,ZA,ZB)
,
MDP-8.(-,A,B,Z,ZA,ZB)
,
MDP-16.(-,A,B,Z,ZA,ZB)
U6 series Control
Units are dedicated to use with 4-20mA transmitters/gas detectors type
DEX
®
/P
and
DG/P
series made
by GAZEX. It is possible to connect
DEX
®
/F and
DG/F
type threshold detectors too.
In the remainder of this Instruction, the term "detector" or "DEX" will refer to DEX/P or DG/P
detectors for all types of gases, the term “MDP” will refer to MDP for all types, except that the description
will apply to a specific type / model.
The MDP can control the work of one to four (MDP-4…), to eight (MDP-8...) or up to sixteen (MDP-
16...) detectors in the measuring or threshold version. A K-8P or K-16P cable hub in
version U4
or later
can be used for cooperation of MDP units with detectors. MDP-4 don’t require in cooperation with the
measuring detectors a cable hub, and in cooperation with at least one threshold detector needs a K-8P
hub.
The MDP...-Z... unit can control independently the work of two MAG-3 shut-off valves.
Features and functions performed by MDP:
♦
supplies (9VDC) individual detectors - can work with measuring detectors 4-20mA: DEX/P, DG/P and
DEX/F and other threshold detectors manufactured by GAZEX, as well as with detectors equipped
with relay output;
♦
monitors the status of a wired connection with the detectors (ensures complete detection of
emergencies, clearly defining the type and location of faults);
♦
controls the value of current drawn by the individual detectors and in case of failure of any one of
them automatically disconnects the power without blocking the work of other detectors (independent
hardware and software protections);
♦
assigns - three alarm levels to each measuring detector: two, A1 and A2 - set by the user to any value
in the full range (A1
≤
A2
≤
100% of range), third, A3 constant - determines the range exceeding the
detector; - two alarm levels A1 and A2 to each detector;
♦
allows calculation of the weighted average TWA and average STEL for measuring toxic gas detectors
♦
allows to specify the type of display measuring units: [%] range, [% LEL], [mA] or [ppm];
♦
allows assigning individual detectors to one of two zones to control various external devices,
depending on in which group of detectors alarm occurred (in fact it creates two detection systems);
♦
the MDP unit in version …Z controls operation of two shut-off valves and controls the efficiency of the
wired connection of the unit to the valves (one valve is assigned to one zone);
♦
allows the additional three modes of operation: SILENT MODE - silences the internal piezoceramic
buzzer or temporarily blocks (for 15 minutes) the signalling device at output A2 (12V voltage);
SERVICE MODE - temporarily deactivates outputs of the unit; AUTO RESET - automatically resets
memory status of outputs and inputs on the unit’s display after decay of emergency state,
♦
allows for closing the valves by manual triggering of output control signals (no need for generation of
detectors’ alarm signals);
♦
signals fault states and alarm states through generation of proper messages on graphical LCD
display and turning LED lams on, as well as by means of acoustic signals (in-built buzzer);
♦
allows to select the type of messages displayed on the LCD screen between the measuring window,
that includes the current detector signal values scaled in measuring units, or a treshold window, that
contains messages about alarms and fault of MDP
♦
stores in non-volatile, internal memory the last 1,600 events in 1600 with corresponding start and end
times and with origin of the event;
♦
allows very precise setting of alarms’ delays and constancy of those parameters in time thanks to
microprocessor control;
♦
allows for 12VDC supply of additional equipment;
♦
by alarm inputs (galvanically separated) allows for cooperation with additional devices and units
(cascade);
♦
12VDC alarm outputs. control additional acoustic and optical signalling devices
♦
relay outputs (galvanically separated from the system) control fans, motors, contactors,
information boards, or connect with building’s/facility’s automatics;
♦
activation of outputs depending on the number of alarms on the inputs: at least 1 or 2 detectors
in alarm;
♦
relay output "FAULT" (galvanically separated) indicates the failure state of MDP, damage to
fuses, damage to line connecting the detector or power failure;
♦
RS232 serial communication channel can work in two modes:
Printer mode
or
Modbus/RTU
- cooperation with control system of an “intelligent building” (after application of
RS232/RS485 converter).
MDP-4(8,16)… Instruction Manual
edition 6PU63en
©gazex’2011 v1101
Page 2
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