SECTION I
GENERAL INFORMATION
© Midmark Corporation 2002 SF-1803 Page 1- 4 Printed in U.S.A.
closed High Limit Switches and to terminals J3 & J4 on
the Main PC board and to the Heating Element energiz-
ing it.
• The Air Valve is closed until power is supplied thru K5
(Air Valve) contacts thru J5 connector, terminals 5 & 6
thru the two normally closed High Limit Switches and to
terminals J6 & J7 on the Main PC board to the Air Valve
energizing it (Opens).
• The operation of the Air Valve is controlled by the soft-
ware of the Main PC board. The Temperature Probe (J12
connector) and the Pressure Transducer on the Main
PCB monitor the conditions inside the chamber. During
the Heat Up Mode the software will energize the Air
Valve, opening it, to expel air from the chamber. This will
occur three (3) times during the Heat Up Mode. Pressure
at which the Air Valve opens (3.0 or 13.6 PSIg) and the
amount of time (38 to 72 seconds) it is opened is con-
trolled by the software.
Sterilization Mode:
(Display: STERILIZING)
• During Sterilization Mode the steam temperature and
pressure are maintained at their set points for a period of
time (determined by cycle selected).
• This is done by monitoring the internal chamber temper-
ature (Temperature Sensor, J12) and pressure (Pressure
Transducer) and utilizing the software to manipulate
(turning On & Off) the Heating Element.
• When the Heating Element is On, K1 (Heater) contacts
are closed supplying line voltage thru J5 connector, ter-
minals 5 & 6 thru the two normally closed High Limit
Switches and to terminals J3 & J4 on the Main PCB to
the Element.
• The Vent Valve (normally open) continues to be ener-
gized (Closed) during the Sterilizing Mode. Power is sup-
plied thru K4 (Vent Valve) contacts thru J5 connector,
terminals 5 & 6 thru the two normally closed High Limit
Switches and to terminals W5 & W6 on the Main PCB to
the Vent Valve energizing it (Closed).
• Final ten (10) seconds of Sterilization Mode READY TO
VENT is displayed to indicate the system will be venting.
Vent Mode:
(Display: FAST VENT)
• The Vent Valve is normally open
when not energized.
During the Vent Mode the pressure inside the chamber is
evacuated and the temperature reduced by opening the
vent valve (removing power from it) and turning off the
heating element. The chamber is vented thru the con-
densing coil inside the reservoir.
• Fast Vent:
On all pre-set cycle types such as
UNWRAPPED. The Vent Valve is left opened until cham-
ber has been completely evacuated.
• Slow Vent:
Available on the two programmable (1&2)
cycles. The Vent Valve is opened and closed at a rate of
one (1) second open, 59 seconds closed until the cham-
ber has been completely evacuated.
• To operate the Vent Valve power is supplied thru K4
(Vent Valve) contacts thru J5 connector, terminals 5 & 6
thru the two normally closed High Limit Switches and to
terminals W5 & W6 on the Main PCB to the Vent Valve
energizing it (Closed).
• The Temperature Sensor, J12, and pressure (Pressure
Transducer) monitor the internal chamber conditions dur-
ing the Vent Cycle.
Door Open Mode:
(Displays: DOOR TO OPEN or
OPEN DOOR TO DRY)
• The M9 & M11 use an automatic door opening feature.
On M9D & M11D (defeatured) the door must be opened
manually. The following explains the automatic feature.
• The Door Opening Motor Assembly consist of a syn-
chronous motor and a normally closed (when un
oper-
ated) switch connected to J15 on the Main PCB.
• The Vent Valve is not energized
, remaining Open.
• Power is applied to the Air Valve, opening it, from termi-
nal 5 of connector J5 thru K5 (Air Valve) contacts thru the
two normally closed High Limits switches to terminals J6
& J7 to the Air Valve.
• The Main PCB monitors the internal chamber pressure.
When the pressure reaches 0.725 PSIg or lower K3
(Door) contacts close.
At the same time the Main PCB initiates a 35 second
timer. This time lapse, until the unit displays DOOR TO
OPEN or OPEN DOOR TO DRY, is to allow pressure in
the chamber to settle to safe levels and to keep the door
from opening too hard regardless if the unit has auto-
matic or manual door opening.
• Power is supplied thru J5 connector, terminals 5 & 6
thru the two normally closed High Limit Switches and to
connector J15, pins 1 & 3 on the Main PCB.
Though line voltage is always present on the white and
black leads, the Switch contacts are being held open by
the motor lever arm preventing the motor from operating.
• The Main PCB also supplies line voltage to pins 1 & 2 of
J15 connector but only for 12 seconds
. Current is sup-
plied to the motor thru the white and red leads of the har-
ness operating the motor.
• As the motor rotates, the motor lever arm disengages
the switch. The switch contacts return to the Normally
Closed
position. This creates a second current path to
the motor thru the white and black leads of the harness.
As the motor shaft rotates, the attached linkage opens
the door.
• When the motor lever arm contacts the stop on the
motor mounting bracket the motor reverses directions,
returning to the start position, opening
the Normally
Closed contacts on the switch and removing power from
the motor. The motor assembly and linkage remains in its
original position awaiting the next operation.
DRY Mode:
(Displays: DRY MODE)
• During Dry Mode, the load inside the chamber is dried
for a certain amount of time chosen when the preset or
programmable button was selected.
• The Heater Element is turned On and Off by the Main
PCB according to a preset (timed) duty cycle. • When the
Heating Element is On, K1 (Heater) contacts are closed
supplying line voltage thru J5 connector, terminals 5 & 6
thru the two normally closed High Limit Switches and to
terminals J3 & J4 on the Main PCB to the Element.
Rev. 8/04/03
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