BCI Capnocheck Plus - Page 24

Chapter 3: Capnocheck Plus Circuit Description
SIGNAL DESCRIPTION
Fioz Voltage proportional to FiO2 concentration.
НАСТ Signal used by microprocessor to turn power off.
1100 Strobe to U6 to read input data and to U7 and U8 to latch output data.
ON-STBY Line connected to the O/l key.
PFI,
/PFO Power fail input and output signals, used to shut down the monitor if battery
is too low.
PWR-LED Used to light green “CHARGE” LED on the keypad.
PSCLK Clock frequency 576KHZ used for Isolated Power Supply
PHI Clock signal generated by microprocessor,
PRESS Voltage proportional to the CO2 cell absolute pressure. Equals to the output
of the pressure sensor divided by two.
PUMP Signal to turn pump on and off.
RD, WR, Signals used by microprocessor to control memory and peripheral devices,
/ME, E /IOE
ВЕЗЕТ Microprocessor and peripheral devices reset signal.
7RAM Signal used to enable RAM
RA12-RA16 Address lines to select RAM page.
(ROM Signal used to enables ROM
ARTCS Signal used to select Real Time Clock chip.
RXS RXS is the microprocessor's high-speed, synchronous serial input receiving
data
signal.
STBY Input signal indicating that I/O key was pressed.
SCLK Synchronous communication clock line.
TX0, RXO, Asynchronous serial communication signals used to control external
CTS0 optional printer.
TX1, RX1 Asynchronous serial communication signals used to communicate with
Little Oximeter Board.
TXS TXS is the microprocessor's high-speed, synchronous serial output
transmitted data signal.
VALVE Signal to turn valve on and off.
VBATT Signal used to monitor battery voltage.
+VBATT, Positive and negative battery wires.
-VBATT -
VCO2 CO2 bench output voltage, indicates CO2 concentration.
VLED Unregulated power from external Charger.
+VP Unregulated power either from battery of from external Charger.
V-RAM +5 VDC voltage when unit is on, or +3VDC voltage if unit is off. Used to
continuously power RAM and Real Time Clock.
VREF, 2.500V | 2.500 VDC reference voltage.
3-10
Capnocheck
Plus
Service
Manual