Haemonetics ACP 215, Руководство по обслуживанию

Страница: 36 / 186

36 Equipment Description
P/N: SM-ACP215-01-EN(AB) Haemonetics
®
ACP-215
®
Service Manual
is a display device that receives commands from the CPU through the display
distribution board and generates characters to communicate information to the
user. The display distribution board coordinates signals between the CPU and
the control panel/vacuum display. The display distribution board manages
keyboard and LED information transfer between the distribution board and the
CPU.
DPM/SPM
The draw pressure monitor (DPM) and system pressure monitor (SPM) are
pressure transducer devices used to measure pressure in the disposable set
at two key locations. The DPM on the left side of the device constantly monitors
pressure on the blood line, and ensures the RBC bag is properly emptied.The
SPM on the right side of the device measures pressure at the outlet of the bowl,
which is generated by pumping fluids in the bowl and changing the speed of
the centrifuge, such as acceleration or braking. This pressure indicates
whether excessive positive or negative pressure has been generated inside the
bowl and thus ensures the rotating seal integrity/air tightness.
Both monitors have sensors that monitor the position of the white sleeve. The
sleeve is pushed in when the disposable filter is mounted, and the position
sensor reports on the position of the sleeve to indicate that the filters are
properly installed. For information concerning the proper installation of each of
the disposable sets please refer to the appropriate protocol operation manual.
Circuit Description
Pressure sensing circuit
A gauge pressure sensor which produces an output of ± 100 mv for an input of
±15 psi is used to monitor pressure. A ten-volt reference provides excitation
voltage, while a differential amp buffers and scales the sensor output so that
±512 mmHg results in a ±2.4 volt level. For test purposes, test signals
low test
and high test are provided. When low test is active, a resistor is selected to
unbalance the bridge sensor, providing the equivalent of a -150 mmHg
pressure input. When the
high test is active, a second resistor provides the
unbalance, providing the equivalent of a +390 mmHg pressure input.
The two pressure signals are read into the CPU board through the top deck
distribution board and backplane. The input is fed through an op amp to a dual
4-to-1 analog multiplexer, and then fed to the 8-to-1 channel multiplexer
channels 3 and 4. The output from the multiplexer is connected to the +VIN
input of the sample and hold amplifier. Its output is connected to AIN of the A/
D converter, where the information is used to control the pump speed (DPM
input), or to respond to a bowl system over pressure (SPM input).
Sleeve position circuits
Hall effect sensors detect the magnetic field of a magnet mounted on the sliding
filter sleeve. When the sleeve is extended, the interlock signals m5
VDC. When the sleeve is depressed and the hall effect sensors detect the