Control Board
Principles of Operation
Force FX-8C Service Manual 4-5
When resistance between the Patient Return Electrode receptacle pins
exceeds 20 ohms, the REM Alarm indicator flashes red, a tone sounds
twice, and RF output is disabled. The indicator remains illuminated red
until you correct the condition causing the alarm. Then, the red indicator
light is extinguished and RF output is enabled.
For additional information, refer to REM Circuit later in this section.
Control Board
Refer to Section 9 for components and the Schematics Supplement for
Board Drawings and Schematics.
The Control board contains the circuitry that controls the generator,
including the indicators and switches on the Display board and the RF
output stage on the Power Supply/RF board. Firmware on the Control
board performs many diagnostic and initialization routines. Errors are
reported as alarm numbers on the front panel.
The Control board interfaces with the Power Supply/RF board through a
96-pin card edge connector. It interfaces with the Display board through a
64-pin ribbon cable.
Microcontrollers
Two microcontrollers on the Control board control the Force FX-8C
generator. These microprocessors communicate with each other through a
shared RAM. The main microcontroller (U5) performs all system
functions, except the time-critical real time feedback control of generator
RF output. The feedback microcontroller (U11), which is a separate,
dedicated microcontroller, handles the time-critical real time feedback
control of generator RF output. All system analog signals are available to
these microcontrollers.
A third microcontroller (U9) functions as an application-specific
integrated circuit, or ASIC. It generates the RF drive waveforms (T_ON\)
for the RF output stage.
Main Microcontroller
The main microcontroller (U5) is an 80C562 that incorporates an 8-input
multiplexed 8-bit A/D converter. The main microcontroller is responsible
for overall system control. It monitors all dosage error functions and
safety circuits. It implements the user interface, including activation
control. It is primarily responsible for these functions:
• Segment display drivers and LED update
• Power control buttons, mode buttons, and the activation interface
• Serial port interface
• Alarm handling
• REM
To Next Page
Loading...
