Control Board
Principles of Operation
Force EZ-C Series Service Manual
5-9
If the code received by the T_ON ASIC is not valid, the internal program sets an
error flag, deactivates all output signals, and remains in an error state until the
system is reset.
T_ON Average Check
Hardware integrates the T_ON waveform generator output waveform and
returns it 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 signal rests at 5 V when the generator is inactive and drops to
the calibrated value when activation occurs. The main microcontroller checks to
make sure the T_ON average signal is within ± 15 counts of the calibrated value.
During spark control in the cut modes or wak control in the coag modes, the
T_ON average rises an indeterminate amount. Due to this unknown, the system
allows the T_ON average to rise to 253 counts, which guarantees the T_ON
waveform generator is still operating. It still does not allow The T_ON average to
drop below the lower limit of 15 counts mentioned above.
Audio Alarm
The audio alarm circuit resides on the Power Supply/RF board. Software and
hardware control the audio alarm:
•
The UP_TONE\ and LO_TONE signals generated by the main
microcontroller in response to activation inputs, alarms, and power-up provide
software control.
•
The RF_TONE\ signal generated in the RF output stage by RF sensing
circuitry on the Power Supply/RF board provides hardware control.
Serial Interface
The RS-232 serial port is a software-polled interface to the main microcontroller
(U5). It provides diagnostics and calibration to an external device (for example, a
computer) connected to the port. Transmission and receipt of command strings do
not stop real time processing, except as single characters are read from or written
to the serial port. The serial port configuration is the following:
•
9600 baud
•
8 data bits,
•
1 stop bit
•
no parity
The system derives this timing from the main microcontroller oscillator frequency
of 11.0592 MHz.
The Control board serial port signals connect to the Power Supply/RF board
through the 96-pin connector. The signals then connect to the 9-pin serial port
connector on the Power Supply/RF board.
