Vent Inop Led Current Check; Error Line Control (Elc) Circuits; Error Led; Diagnostic Interface - Respironics BiPAP Vision Service Manual

Chapter 3
Theory of Operation
3-16
3.4.10

Vent Inop LED Current Check

An internal test verifies that the Vent Inop LED current is acceptable.
3.4.11

Error Line Control (ELC) Circuits

Redundant error signaling circuitry communicates error conditions among the
subsystems to minimize the chance of communication failures.
3.4.12

Error LED

The error LED lights to indicate that an error condition has been detected.
3.4.13

Diagnostic Interface

The diagnostic connector (J5) interfaces with the microprocessor so the DCS
board can download its diagnostic data to a service laptop computer for units
built s/n 105999 and below. For units built s/n 106000 and above, J5 sends
TDS/RDS data to J6 of the MC board, which processes the information then
sends it to the RS-232 connector on the back of the unit.
3.4.14

EEPROM

A serial EEPROM stores the set points for the backlighting and contrast, and
for the appropriate diagnostic data.
3.4.15

LCD Controller

The LCD controller interfaces with the display.
3.4.16

Debouncing/Keypad Matrix

The matrix keys are debounced and the microprocessor scans the matrix to
determine what key was pressed.
3.4.17

Rotary Encoder Control

The rotary encoder control circuit detects the following within one detent of
movement: relative position, direction, and speed of the rotary encoder.
3.4.18

Audible Alarm Activation

The audible alarm is activated by either an input from the ELC, the power fail
circuitry, or the test alarm signal from the MC board. An audible alarm also
occurs when an incorrect key is pressed, an adjustable parameter has reached
its limit, or the error signal has been activated.
BiPAP Vision Service Manual © Respironics, Inc. 1062788