CAUTION
As the alarm panel monitors specific resistance values, only one input
sensor (for each specific gas service) may be connected to an alarm
panel. Similarly it is not possible to connect more than one alarm panel to a
single input sensor.
1.9 Remote audible warning devices
Remote audible warning devices may be fitted in locations where warnings
are necessary and alarm panels are not fitted. Remote audible warning
devices are housed in a surface mounted enclosure containing a warning
buzzer. The audible warning device is connected by input cable to the power
supply pcb within the alarm panel (alarm terminals + and AL). When the
alarm panel audible sounds the remote audible also sounds. A maximum of
four remote audible warning devices can be fitted to an alarm panel and
the cable length should not exceed 50 metres.
1.10 Medipoint 125 Relay interface panel
A dedicated relay interface panel assembly enables the Medipoint 125
medical gas central alarm system to be interconnected to an event
recording circuit of a building management system, or other suitable alarm
system. The relay interface unit is housed within a standard alarm panel
enclosure and provides a fascia display of both POWER ON and SYSTEM
ALARM. The relay interface panel incorporates a dedicated power supply
pcb and a dedicated relay printed circuit board. The power supply pcb
provides no-volt terminals (C, 1, 2, 3, 4) for each channel CH1 to CH5 to
interconnect with a BMS system. The relay printed circuit board is similar to the
standard light display board, except that the gas service alarm LED’s are
replaced by normally open low voltage relays. With the gas service operating
normally, relay contacts are closed providing continuity between terminals C
and 1, 2, 3, 4. In the event of a gas service failure the respective relay
contacts open to break the continuity between terminals C and either 1, 2, 3
or 4. Relays are connected to the BMS system at terminals C, 1, 2, 3 and 4
and are rated at a maximum voltage of 50V d.c. with a maximum current of
50mA.
1.11 Operation of the alarm system
Each Medipoint 125 medical gas alarm panel is connected to the mains
electrical power supply and operates by 15V and 5V d.c. circuits from it’s
integral transformer. Service failure sensors provide the input to initiate both
the visual displays and audible warning.
Programming of the panels is done via switches which can be easily
adjusted on site from within the panel.
The Medipoint 125 medical gas panels use coloured LED’s to indicate the
service conditions. The green NORMAL indication is a steady light, whilst the
service failure displays illuminate as flashing lights to draw attention to the
failure. During normal conditions, the green NORMAL LED is illuminated.
Should a service failure sensor open, the green (NORMAL) LED is extinguished
and the appropriate service failure sensor is illuminated (flashing) together
with an audible warning. The audible warning continues until either the MUTE
switch is operated or the gas pressure returns to NORMAL. If the MUTE facility is
operated and the alarm condition remains, the audible warning will re-sound
after 15 mins and a further MUTE selection will be required. Should a further
alarm condition occur after the panel has indicated a fault and has been
muted, the audible warning is re-activated.
Operation of the TEST switch illuminates (flashing) all LED’s and operates the
audible warning.
The relay output (N/O and C) may be interconnected to a suitable system.
The contacts are closed when all gas services are indicating NORMAL. In the
event of any alarm condition, the relay contacts open, breaking the circuit to
the remote system. The relay contacts remain open until all alarm conditions
return to NORMAL condition. There is also a line contact monitor integral to
the board available across the N/O and C contacts. To select this the jumper
on LK4 is moved to the A position, for totally volt free contacts the jumper is
moved to the B position.
The green POWER ON LED is normally illuminated and is extinguished in the
event of an electrical power failure.
The red SYSTEM ALARM LED is normally extinguished and illuminates (flashing)
together with an audible warning, in the event of any of the following failures:-
Alarm contact line fault.
Electrical power supply failure. (powered by standby battery).
Internal alarm circuit failure.
Data transmission failure.
1. DESCRIPTION AND
OPERATION
1.8 Alarm contact line fault
continued
