4 Theory of Operation
41
I/O Boards
A single MIB/RS232, LAN, PS/2, USB, or Flexible Nurse Call Relay board can be added optionally.
An I/O board with three general relays and one dedicated to the power loss condition*
1
. All relays
provide both polarities (active closed, or open contact) at their output. The general relays (#1...#3) can
be flexibly configured by the user. Usually they are used to indicated red and yellow alarms.
The board provides one phone jack for backwards compatibility that is connected to the active closed
contact of the relay #1, and one full-featured connector with all contacts of all relays. This boards must
be plugged into the I/O slot designated for its functionality.
*1: The power loss indication functionality of the Flexible Nurse Call Relay board is not supported with fetal monitors.
Fetal Recorder (Thermal Printer Unit)
The fetal recorder is located in the Top Cover Assembly. The recorder consists of the following major
parts:
•
Recorder Adapter Board
•
Thermal Line Printhead (TLPH)
•
Paper Sensor
•
Stepper Motor
Recorder Adapter Board
Recorder signals are handled by the Recorder Adapter Board (M2703-66430), connected to the Main
CPU Board. Video signals to the display are also wired through this board, and connection to the
Display Adapter Board is made via a silver-colored 50-pin ribbon cable.
The recorder unit, including the TLPH, is connected to the Recorder Adapter Board via a white 50-
pin, ribbon cable. The stepper motor and the paper sensor are also connected to the Recorder Adapter
Board. The Recorder Adapter Board is connected to the Main CPU Board via a 154-pin connector.
Thermal Line Printhead (TLPH)
The TLPH is located on its own holder in the recorder chassis.
Paper Sensor
The paper sensor hardware consists of a reflective light sensor that detects the black marks on the trace
paper, and paper-out. It is attached to the RFI Bracket, and connected to the Recorder Adapter Board
via a removable cable connector.
Stepper Motor
The stepper motor is a bipolar motor controlled by a micro-stepping motor driver on the Recorder
Adapter Board. The motor is located on the recorder chassis, and is connected to the Recorder
Adapter Board via a removable cable connector.
Summary of Contents for Avalon FM20
Page 2: ......
Page 6: ...6 ...
Page 38: ...3 Installation Instructions 38 ...
Page 46: ...4 Theory of Operation 46 ...
Page 155: ...10 Repair and Disassembly 155 11 Put the two halves of the display assembly together as shown ...
Page 167: ...10 Repair and Disassembly 167 10 Remove the four screws holding the recorder chassis ...
Page 169: ...10 Repair and Disassembly 169 12 Remove the RFI bracket 13 Lift out the recorder chassis ...
Page 254: ...12 Specifications 254 ...
Page 259: ......
Page 260: ...Part Number 453564541271 Published in Germany 11 14 453564541271 ...