6
3.2.3
Internal components
(2) Pipework on the vacuum side
The pipework on the vacuum side connects the
connection nipple (1), the exhaust air valve (3), the
pressure transducer (15) on the processor board (14)
to the pump (4, vacuum connection). The pipework is
manufactured complete with silicone hoses
.
(3) Exhaust air valve
The exhaust air valve (3) serves to reduce the vacuum,
if the system (collection jar, etc.) is shutdown. The valve
is controlled by the processor board (14) with 12V dc.
The function can be tested in Service Mode 2.
(4) Pump
The pump (4) is supplied with mains voltage through the
processor board (14). The processor controls the pump
(4) until the preset vacuum is reached. When the vacuum
is reached the power supply is switched off. The function
can be tested in Service Mode 2.
(5) Start valve
The pump (4) does not start automatically under vacuum.
Therefore, when necessary the vacuum in the pumping
head of the pump (4) is reduced by the start valve. Since
the valve is located in the intermediate piping of the pump,
no reduction of vacuum occurs on the vacuum side. The
control of the valve (5) is done by the processor board
(14). The processor uses the running signal of the pump
which is reported by the control wire (11) to the processor
board to recognise a start.
(6) Pipework on the pressure side
The piping on the pressure side connects the pump
(4) with the silencer (7). The piping is made of silicone
hoses.
(7) Silencer
The silencer is integrated into the housing. The exhaust
air hose (6) is clamped in the silencer housing and se-
cured with 5 screws and a cover plate. Noise absorbing
padding is fi tted in the silencer housing to absorb the
noise. The air passes out of the back of the housing to
the outside.
(13) Fan
The fan serves to cool the pump (4) and generally to
cool the inner space. The fan is supplied with 12V dc
by the processor board (14). The fan switches on at a
temperature of 45
°
C and off at a temperature of 40
°
C on
the temperature transducer (16).
(14) Processor board
The processor board serves to control and monitor the
ATMOS S 351. It forms the central unit. On the processor
board there is the processor, the power supply for the elec-
tronics, the pressure transducer (15) and the temperature
transducer (16).
(18) Display and keyboard
The display and the keyboard are directly connected to
the processor board (14) with the ribbon cable (17). On
the ribbon cable (17) there are 2 ferrite cores for fault
clearance. The display is a graphic LC display with 128 x
64 pixels. The lighting is done by means of LEDs.
(22) Foot controller connection
In the standard component ATMOS S 351 the connection
is done directly through cable (23) to the processor board
(14). The foot controller connection consists of a 9 pole
Sub-D-Bush.
(25,27,29) Overfl ow contacts (left, trolley, right)
The overfl ow contacts are connected through the con-
nection wires (24, 26, 28) to the processor board (14).
The overfl ow recognition is done by a resistance measu-
rement.
(30) Mains input
The mains input consists of a cold device connection
box with integrated fuses and an EMC-fi lter. In addition a
potential equalisation bush is connected here.
3.0 Unit function and unit construction
