Display Board Assembly; Chapter 4 - Principles Of Operation (Continued); Microcontroller; Comparator/Safety Monitor - CareFusion Alaris 8110 series Service Manual

PRINCIPLES OF OPERATION
GENERAL INFORMATION (Continued)
4.2
Both the Syringe and PCA Modules include
display, logic, drivetrain, drive head, plunger,
and force sensor subsystems.
NOTE: All circuit boards in the Syringe and
PCA Modules are not field repairable and
must be returned to a CareFusion
Service Center for repair.
4.3

DISPLAY BOARD ASSEMBLY

The keypad sends signals to the
microcontroller on the Display Board, whose
function is to manage displayed information.
The Logic Board provides
Display Board through a

4.3.1 Microcontroller

The Display Board's microcontroller
provides four keypad functions: Channel
Select, Pause, Channel Off, and Restart.
The microcontroller controls the keypad
backlight and the Alarm, Infusing, and
Standby s.
LED
The microcontroller controls the
driver for the Channel Identification
(Channel ) and
ID
The microcontroller also drives the scrolling
alphanumeric display that shows module
status (such as "
"
CHANNEL MALFUNCTION
The microcontroller performs safety
monitoring and generates alerts (including
the Alarm LED and applicable error
messages) if critical circuitry does not
function properly.
4.3.2 LED Display Driver
The microcontroller communicates serially
with the LED driver for the
-segment
7 LED
4-2
Alaris Syringe Module (8110 Series)
®
Alaris PCA Module (8120 Series)
®
Technical Service Manual
power to the
5V
-pin connector.
10
LED
–segment rate displays.
7
INFUSION COMPLETE
").
-digit,
8
display.
The display driver uses a discrete resistor
for brightness control. Module software
provides three brightness levels: low (
full brightness), used when the PC Unit is
operating on battery power; medium (
full brightness), used when the PC Unit is
operating on
brightness) is the maximum level possible.
Rate:
The display driver controls the five
–segment displays used for the Rate
7
display: three
small
displays show fractional digits). The five
displays show infusion rates from
to
999
normal hospital lighting conditions from a
distance of
viewing angle.
Channel Identification:
The display driver controls the
Channel
through
A
readable in normal hospital lighting
display
conditions from a distance of
provides a

4.3.3 Comparator/Safety Monitor

The comparator/safety monitor circuit
" or
detects short or open failures of the Alarm
LED
information to the microcontroller. This
ensures correct alarm notification and
prevents the module from displaying an
invalid infusion rate.

4.3.4 Status and Backlight LEDs

A constant current drives and ensures
consistent brightness levels for the three
status
the keypad backlight
power; and high (
AC
–segment displays and two
7
–segment displays (
7
mL/h. The Rate display is readable in
feet and provides a
15
display, which can display letters
ID
. The Channel
H
viewing angle.
45°
or rate display and sends that
s (Alarm, Infusing, Standby) and
LED
LED
of
27%
47% of
100%
he smaller
t
mL/h
0.01
45°
–segment
14
display is
ID
feet and
15
.