5
the unit from patient service and call the Porter Technical Service Department at 1-888-723-4001. To aid in the
diagnostics of the unit, make note of the final error code displayed.
Description of Unit: The DIGITAL MDM mixer consists of a Control Unit attached to a Base Unit via an
Interface cable. Note - Control and Base Units are calibrated together and must remain together
(
match
serial numbers on each unit). Only use Porter Interface cable (EMI protection).
The Control Unit interface is
shown in Figure 1. The device permits the operator to adjust the percent of oxygen through a range of 100% to
30% (and thereby control the ratio of oxygen to nitrous oxide). The operator can also control the total volume of
mixed gas up to 9.9 liters per minute.
Mixture Control:
The DIGITAL MDM mixer precisely mixes oxygen and nitrous oxide from local cylinders or
pipeline gas systems, and delivers the electronically controlled mixture to the bag tee outlet.
Built-In Safety:
A series of alarms (see Safety Alarm System page 6) alert the user to any problem condition
within the DIGITAL MDM mixer unit or in the gas supply.
Displays and Indicators:
In the following, the location numbers refer to Figure 1.
Flow Display:
The LPM FLOW display (4) normally displays the total gas flow rate. It also displays the individual
nitrous oxide or oxygen flow rates when either the N
2
O or O
2
flow display controls (6) are pressed. The gas flow
being displayed is indicated in the flow indicator (5) by O
2
, TOTAL or N
2
O.
% OXYGEN Display:
The % OXYGEN display (3) indicates the oxygen concentration set point in the total flow.
Gas Flow Indicators:
Gas flow is indicated by bar graph LEDs (1). A green bar graph represents O
2
while blue
represents the N
2
O flow. The number of lit bars gives a graphical indication of the flow level of a particular gas.
Figure 1. PORTER DIGITAL MDM Mixer Control Unit Front Panel
(figure shows all LEDs illuminated)
