Pressure Sensor Subsystem (Syringe Module Only); Patient Handset Circuit And Door Lock Sensor Circuit (Pca Module Only) - CareFusion Alaris 8110 series Service Manual

4.8 FORCE SENSOR SUBSYSTEM
(Continued)
This mechanical advantage amplifies the
input for a given force from a syringe, which
improves system resolution. Improved
resolution is particularly beneficial for
smaller syringes with lower syringe forces.
A protrusion on the contact plate
concentrates force from all syringe sizes to
a specific location on the contact plate,
which minimizes the effect of variations in
syringe loading and in the syringe push
button geometry inherent in plastic syringes.
The protrusion also creates a longer
moment arm for smaller size syringes,
because they contact the protrusion further
from the contact plate pivot. This increases
the sensor force of small size syringes,
allowing better system resolution. A silicone
seal is also trapped between the force
sensor and the lower housing.
4.9 PRESSURE SENSOR SUBSYSTEM
(SYRINGE MODULE ONLY)
The pressure sensor subsystem includes
the Pressure Sensor Board Assembly, disc
detect system, and related hardware. The
pressure sensor subsystem is only activated
when an administration set with a pressure
disc is used and the pressure disc is
installed, and enhances overall pressure
detection in the patient line.
The Pressure Sensor Board includes: a
pressure sensing transducer that makes
intimate contact with a flexible membrane
(pressure disc) on the administration set.
The pressure of the fluid in the
administration set is transmitted through the
membrane and into the gel of the sensor,
where it is measured by a piezoresistive
pressure transducer.
PRINCIPLES OF OPERATION
Circuitry on the Pressure Sensor Board
amplifies pressure transducer output. The
board also includes an optical switch that
detects the presence of an administration
set pressure disc.
4.10 PATIENT HANDSET CIRCUIT AND
DOOR LOCK SENSOR CIRCUIT (PCA
MODULE ONLY)
The PCA Module Logic Board includes a
patient handset circuit, which senses
whether a dose request cord is attached. A
button on the dose request cord allows a
patient to request a dose of analgesia
according to clinician-programmed
parameters.
The PCA Module Logic Board also includes
a door lock sensor circuit that detects the
position of the door lock (
, or
PROGRAM LOCK
• allows syringe loading or
UNLOCK
unloading, or access to the latch that
allows the PCA Module to be detached.
• allows changes to
PROGRAM
programmed parameters without
interrupting an infusion.
• is the only position that allows an
LOCK
infusion to start.
Alaris Syringe Module (8110 Series)
®
Alaris PCA Module (8120 Series)
®
Technical Service Manual
,
UNLOCK
):
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