Valleylab Force FX-C - T_ON Average Check; Audio Alarm; Serial Interface

Force FXThLC Service Manual
Control Board
Each code generates a unique waveform pattern to be delivered to the RF
output stage of the generator. 111." T_ON ASIC reads and evaluates the
code and, if the code value is acceptable, repetitively generates the
appropriate wa\'eform until the acti\'ation request ends. After the request
ends, the feedback microcontroller the T_ ON ASIC back into reset.
If the code received by the T_ ON ASIC is not valid, the internal program
sets an error nag, deactivates all output sign.:1.ls, and remains in an error
state lmtil the system is reset.
T_ON Average Check
The T _ON waveform generator output waveform is integrated in
hardware and returned to the main microcontroller as an analog value
called T_ON average. The T_ON average is different for each distinct
output mode of the T_ON waveform generator. The main microcontroller
continually checks the T_ON average for compliance with the calibrated
value to ensure that the T_ON waveform generator is operating properly.
The T_ON average rests at 5 V 'when the generator is not activated
and drops to the calibrated value when activation occurs. TI1e main
microcontroller checks to make sure the T_ON average signal is within
± 15 counts of the calibrated value.
During wak control in the coag modes, the T_ON average rises an
indeterminate amount. Due to this unknown, the T_ON average is
allowed to rise to 253 counts, which guarantees the T",ON waveform
generator is still operating. The T_ON average is still not allowed to drop
below the lower limit of 15 counts mentioned above.
Audio Alarm
The audio alarm circuit is located on the Footswitch board. The audio
alarm is controlled by software and hardware.
• Software control is provided by the UP _ TONE \ (micro controller tone)
and LO _TONE signals generated by the main micro controller in
response to activation inputs, alarms, and at power-up. TI1l'se signals
connect from the Control board to the Power Supply /RF board
through the 96-pin connector and then from the Power Supply /RF
board to the Footswitch board through the 16-pin footswitch ribbon
connector.
• Hardware control is provided by the RF_TONE\ signal generated in
the RF output stage by RF sensing circuitry on the Power Supply /RF
board.
Serial Interface
The 1{5-232 serial port is a sofhvare-poUed interface to the main
microcontroller (U5). Tt is used for diagnostics and calibration.
Transmission and receipt of command do not stop real time
processing, except as single characters are read from or written to the
4-9