GE Dash 3000 Service Manual page 240

Defib Sync
Optional Thermal Printer
Optional Alarm Light Indicator
PC Card
9-16
Assembly Drawings: Theory Of Operation
The QRS complex of ECG data acquired from the DAS generates the
marker-out signal. A software selectable pulse width and pulse
amplitude is provided in the Boot Loader Menu.
The thermal printer includes complete control of the print head to print
the desired waveforms and text as well as monitor power consumption.
The host processor on the main processing board has direct
communication via an 8-bit data bus to the processor residing within the
thermal recorder.
The +9-18 V power supplied to the writer is heavily filtered to provide
the storage capability to smooth power surges and transients caused by
abnormal thermal printing. Such printing may occur if the monitor is
subjected to ESU noise. In addition, a writer current limiting circuit
restricts the current to the writer to 2.5 A. If this current limit is
exceeded, the circuit faults and requires the current limiting circuit to
reset through a microprocessor port.
An alarm light indicating two levels of visual alarms resides in the
handle of the Dash 3000 monitor and in the display bezel of the Dash
4000 monitor. Red and yellow alarm lights illuminate by addressing an
ASIC output port. The Dash 3000 alarm light interfaces to the processor/
power management PCB via the 40-pin writer interface. The Dash 4000
alarm light interfaces to the processor/power management PCB via the
100-pin DAS/Display /Keyboard interface.
The main processor contains a PC Card controller, which complies with
the PCMCIA standard. One 68-pin fully compliant Type II PC Card slot
is supported in this design for RF LAN.
Dash 3000/4000 Patient Monitor
2000966-339
Revision A