Nellcor NPB-75, Service Manual

Page: 15 / 71

Section 4: Service Mode
4-2
monitor. Event messages will be erased when exiting the service
mode by a long press of
.
4.2.3 Interface Test Screen
The interface test screen shows four parameters (listed below) that
provide tools for the user to test, adjust, and calibrate the unit’s
interfacing systems.
• HMI Test
• Light Detector
• Contrast Cal. (Calibration)
• CO
2
Calib. (Calibration)
4.2.3.1 HMI Test
When the HMI Test is turned on, the monitor performs a self-test of the
following sub-systems:
• Buzzer (sounds for one second)
• LCD graphic display (screen shows a checkerboard pattern)
• 7-segment digital display (8s scroll left to right)
• Alarm bar (lights red, yellow, off)
• Backlight (turns on and off)
• Alarm silence indicator (light turns on and off)
When the HMI test is completed, the status field returns automatically to
OFF.
4.2.3.2 Light Detector
The Light Detector parameter allows the service technician to set the
threshold value of the phototransistor. The default value is 1 and the
range is from 1 to 5 with 1 as the most sensitive (backlight on at all times)
and 5 as the least sensitive (backlight off). The threshold value should be
set according to the lighting conditions of the working environment. A
higher threshold value saves on battery power consumption.
4.2.3.3 Contrast Cal. (calibration)
The Contrast Cal. gives the service technician the option to change the
middle point default value of the contrast intensity of the LCD. Refer to
Table 4-1: "Accessing Service Mode and Changing Parameter Settings".
4.2.3.4 CO
2
Calib. (calibration)
The CO
2
Calib. allows the service technician to perform a calibration
check and calibration process to ensure the accuracy of the monitor.
Section 10: Performance Verification describes the calibration check
procedure.
Note: To exit the service mode and save event messages, turn off the