Overload or shorting of any voltage outputs “
12V ALARM OUTPUTS
”
during
A1
or
A2
status
will cause
automatic switching off of automatically reset fuse. After removal of overload or shorting the internal fuse
automatically restarts the normal work after not longer that several seconds.
NOTE!!! To disable the unit in MDP-…B version equipped with internal battery support,
disconnect the external power supply with main switch, then press "OK" button
located on the front panel and hold it down until you disable the MDP unit (for about
10 seconds).
6.3 The final stage of the control system’s operation is to check the MDP unit and generate all
alarm states for all connected detectors and to control the efficiency of external devices.
REQUIRED ASSUMPTIONS OF SYSTEM INSPECTION:
- The
MDP
unit is in normal state (after elapse of the time necessary for burn-in of sensors), the
[POWER
SUPPLY]
light is on, detectors indicated with
“N”
sign are on, the value of concentrations displayed on
LCD screen comply with the “zero level” specified in the instruction manuals of individual detectors.
- The unit was stored for not longer than 2 months or was connected to power supply for at least 24 hours
(version B).
-
DEX/DG
detectors do not generate alarm signals (output current is consistent with the "zero level"
specified in the detector manual);
- In order to obtain a measurement accuracy of the system specified in the manual, should be taken during
inspection of detectors to meet the additional conditions specified in the individual manual for each
detector DEX/P.
6.3.1 Generate alarms of each detector by means o test gas with a known concentration value according to
the instruction manual of the detector. After a time consistent with
input delay
the indication next to the
tested detector should change into
A1, A2
or
A3
on the LCD screen, which is a sufficient confirmation
of correct cooperation of detector set with unit.
If the alarm signal A1 and A2 from the DEX detector will continue for at least the time corresponding to
output delay,
alarm signal on correct contact outputs will be generated in the zone, to which the
specific detector had been assigned (message on LCD screen
A1Z1
and
A1Z2
, green
ALARM1
and
ALARM2
lights will be turned off and a constant sound signal will be activated.
In addition to measuring detectors switch on the LCD measuring screen and see if it appears with the
appropriate detector measured gas concentration is compatible with the given test gas concentration (in
the comparison should take into account the measurement accuracy of the unit, detector and test
mixture).
6.3.2 For MDP-Z - Simultaneously with generation of the alarm state at the control output A2 of the
corresponding zone, two electromagnetic pulses on
VALVE
terminals (message
VAL1
or
VAL2
on LCD
screen) should be generated. Generation of the next A2 state
must
be preceded by a break for
regeneration of internal batteries. The length of that break depends on the initial charging of the battery,
the type of shut-off valves, the number of A2 states generated directly before the next attempt and on
ambient temperature. It needs to be assumed that the break should not be shorter than 5 minutes (10
minutes for two valves) and it should be DOUBLED after each successive attempt (independently of the
fact whether A2 was generated from detectors or with the TEST procedure). After a series of ca. 5
attempts wait for one hour or longer.
6.3.3 After removal of the test gas reduction of gas concentration in the detector takes place, which causes a
change of condition of detector on the LCD screen from
H2
and/or
H1
, depending on completed alarm
state and transition of red lights from constant lighting (if they were lit up) to flashing: first
ALARM2
,
then
ALARM1
. The control outputs are back to normal (alarm messages disappear from the LCD
screen), while the sound signal is changed to intermittent. Information about alarms remains on the
display until willingly cleared by a user.
6.3.4 Check the operation of other detectors in a similar manner. When the status of all alarms is marked on
the LCD screen with
"H2"
- reset the unit by pressing and holding the "OK" button located on the front
panel for 3 seconds. Red lights of “
ALARM1
” and
“ALARM2
”
should go off and the unit should switch
to normal.
Open the valve/shut-off valves!!!
6.3.5 The control procedure 6.3.1 should be complemented with output test conducted with software from the
user menu described in section 5.4.4.
Results of control or start-up should be registered in the attached Periodical Control Protocol.
After a positive test result the GX
Active Gas Installation Safety System
or the
Double-
threshold Gas Detection System
can be considered activated and functional
.
6.4 Screw the cover of the unit’s terminal chamber:
-
tight gland ducts (strong enough to prevent them from transmitting mechanical loads during the attempt
of pull the cable out);
-
seal not used gland ducts (e.g. by tightening short sections of the conduit on them);
-
tightly close the transparent unit cover. Secure opening of the cover by turning the blocking pin with a flat
screwdriver into horizontal position.
-
it is recommended to seal the unit’s cover (to restrict outsiders’ access to MDP unit);
MDP-4(8,16)… Instruction Manual
edition 6PU63en
©gazex’2011 v1101
Page 20
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