7
10545100-Australia Rev.
– 08/2018
SAFETY ALARM SYSTEM
There are four alarm conditions on the Digital MDM Mixer.
They appear in the safety alarm display (see Figure 1, item
2) only when conditions warrant. Otherwise, they are not
visible. The alarm conditions are:
OXYGEN FAILURE:
This alarm indicates that the set
oxygen (O
2
) flow cannot be delivered. Check the oxygen
supply. During an OXYGEN FAILURE alarm, the nitrous
oxide delivery is automatically shut off. The LPM FLOW and
% OXYGEN displays are off.
NITROUS FAILURE:
This alarm indicates that the set
nitrous oxide (N
2
O) flow cannot be delivered. Check the
nitrous oxide supply. During a NITROUS FAILURE alarm,
the LPM FLOW display indicates oxygen flow and the %
OXYGEN display is off.
Both the OXYGEN FAILURE and NITROUS FAILURE are
self-canceling alarms. When the gas is restored, the unit
returns to the flow rate and mixture ratio which were in effect
before the alarm condition.
1 LPM OXYGEN LIMIT:
This message is displayed when
the oxygen flow rate reaches a value of 1 LPM; the unit will
not allow the oxygen flow rate to go below this value. If the
user attempts to lower the % OXYGEN while this message
is displayed, the unit compensates by increasing the total
flow rate.
FLUSH FLOW LOW:
This message indicates that the
oxygen flush flow rate is less than 10 LPM. Check the
oxygen supply pressure.
KEY PAD CONTROLS
CAUTION:
Operate key pad with finger
pressure only. Do not use hard or sharp objects.
Failure to do so may result in damage to the
front panel.
On/Off Key:
The ON/OFF key controls the operation of the
unit. Momentarily depressing the ON/OFF key changes
power state from OFF to ON or ON to OFF.
Note:
If the power to the unit is interrupted and then
restored, either by disconnecting / reconnecting the power
cord or by local power failure, the unit will display OFF. The
operator must press the ON/OFF key to restart the unit. The
unit will them display default values of 100% oxygen at 5
LPM.
CAUTION:
After turning the device off, or when
the unit is not in use, all oxygen and nitrous
oxide supply cylinder valves must be closed.
Flow Control:
The LPM FLOW key pad [
▲ or ▼] controls
the total flow rate delivered by the unit. Pressing the
appropriate key momentarily increases or decreases the
total flow rate by 0.1 LPM. By pressing and holding a key,
the total flow rate indication changes slowly for the first two
steps, then changes at a faster rate for the remainder of the
time the key is held. An audible signal indicates that a limit
has been reached.
%O
2
Control:
The % OXYGEN key pad [
▲ or ▼] controls
the percentage of oxygen delivered by the unit. Press the
appropriate key momentarily to increase or decrease the
oxygen percentage one step (1% or 5%). Pressing and
holding the key changes the oxygen percentage slowly for
the first two steps, then faster for the remainder of the time
the key is held. This varies the ratio of oxygen to nitrous
oxide. An audible signal indicates that a limit has been
reached.
Setting % OXYGEN Step Amount (1% or 5%):
The Digital
MDM Mixer is shipped from the factory programmed to
change 1% for each press of the % OXYGEN key pad [
▲ or
▼]. The amount can be changed from 1% to 5% by
performing the following:
1. Press and hold the DISPLAY N
2
O key.
2. While pressing the DISPLAY N
2
O key, press the
DISPLAY O
2
key until the audible alarm sounds.
3. Release both keys.
The audible signal indicates the change has occurred and is
programmed in memory. The unit will remain in the new
mode until this sequence is repeated. Unplugging or turning
the unit off will not affect the programmed mode.
Flow Display Control:
The key pad DISPLAY O
2
or
DISPLAY N
2
O select the gas flow rate displayed on the flow
display. Press and hold the DISPLAY N
2
O key to display the
nitrous oxide component of the total flow. Press and hold the
DISPLAY O
2
key to display the oxygen component of the
total flow. If neither key is held, the LPM FLOW display
indicates the total gas flow.
Oxygen Flush Key:
Pushing the O
2
FLUSH key delivers
100% oxygen directly to the mixed gas outlet at the rear of
the unit. This outlet is connected to the patient through the
breathing tube connector (see Figure 2). While the key is
pushed, 100% oxygen is delivered continuously at an
approximate flow rate of 20 LPM. Releasing the key returns
the unit to the flow rate and mixture ratio which were in effect
prior to the flush.
Note
: Whenever the unit is turned ON an automatic 100%
oxygen ‘flush’ will be briefly delivered to the patient.
Alarm Test/Silence Key:
The alarm test / silence key
serves two functions. When pressed, all the display,
indicators and the audible alarm turns ON. This key also
silences the audible alarm when a NITROUS FAILURE
condition exists. The audible alarm will be silent for about
five minutes and then resume, unless the failure condition
has been corrected
