9
Medical Gas Central Alarm - Medipoint 125 Digital Alarm
4233500107.03
1.4
Visual displays
Colour LCD touch screen display provides the visual
display detailed in paragraph 1.1, figure 1. All flashing
displays flash at a rate of 0.4 seconds on, 0.4 seconds off
in accordance with ISO7396-1 and HTM02-01/HTM2022 .
1.5
Audible warning
The audible warning speaker fitted to the inside of the
alarm panel door and connected to the processor PCB by
plug and socket (see figure 2) operates simultaneously
with any HIGH PRESSURE, LOW PRESSURE or SYSTEM
ALARM indication. The audible warning may be muted
by pressing the MUTE switch (see figure 1). If following
a mute condition another alarm condition occurs, the
audible warning will operate simultaneously with the
indication. Following a mute condition and a continuing
alarm indication, the audible warning will resound after
15 minutes in accordance with HTM02-01/HTM2022 and
C11. When the audible re-sounds further operation of
the MUTE switch is necessary to cancel the audible.
If following an alarm condition no action is taken to
MUTE the audible, the audible warning will automatically
switch off when the alarm condition reverts to NORMAL.
The audible tone consists of a modulation between
two tones (F1 and F2). F1 = 440 Hz and F2 = 880Hz. The
modulation rate is 4 Hz in accordance with HTM02-01/
HTM2022 and C11.
1.6
Printed circuit boards
Two printed circuit boards are fitted inside medical gas
central alarm; a power supply PCB and a processor PCB.
All components are mounted on these PCB’s, which are
interconnected by means of a multi-way ribbon cable
and polarised connector (see figure 2 & 3). The area
central alarm internal electrical installation complies
with all relevant British Standard specifications, IET
wiring regulations and current UK legislation.
1.6.1 Processor printed circuit board
The Processor PCB is retained inside the alarm panel
front cover with four retaining studs. This PCB is supplied
with a ribbon cable for connection to the power supply
PCB, and connector for linking to the control fascia, LCD
touch screen and internal speaker (see figure 6).
The block indicator is a plug-in component enabling easy
replacement or subsequent updating of the installation.
The ribbon cable is permanently attached to the rear face
of the light display PCB and enables interconnection of
circuits with the power supply PCB. The audible warning
speaker is connected by plug and socket to the light
display PCB and locates within the alarm panel front
cover when installed.
1.6.2 Display positions
To provide an aesthetic display and maintain consistency
in accordance with recognised and established medical
gas service sequencing, it is recommended that displays
are positioned in the following sequence on each alarm
panel commencing with from left to right (see figure 7
example):-
Gas Type
Legend
Medical Oxygen
O2
Nitrous Oxide
N2O
Oxygen/Nitrous Oxide Mix (50/50)
O2/N2O
Medical Air 400 kPa
Air
Medical Air 700 kPa
Air-800
Medical Vacuum
Vacuum
Figure 6 - Processor PCB
1
2
3
4
Medipoint 125 consists of: -
No. Description
1
Process to power supply PCB ribbon cable
2
Control fascia connector
3
LCD touch screen connector
4
Audible speaker connector
Figure 7 - Gas source layout example.
