ConMed ExcaliburPLUS PC - Controller Software and Calibration

OO << +++ +
rupts disabled to ignore /IFAIL) to produce a
Waveform reference voltage for power up self
tests and at least once every 500 mSec for each
mode of operation and power setting when
power is on during normal operation. When RF
is activated and the resulting voltage is outside
the reference input voltage provided by the DAC
UI9, AWEMHI will go high if the Waveform
voltage is too high or low if the Waveform volt-
age is too low. Input is then read by the micro-
processor and if the test fails, fatal errors that pro-
duce an “Err 23.2” code occurs and shuts down
the Excalibur Plus PC. Power On Self Test Errors
are “Err 23.0” if the Waveform voltage is too low
and “Err 23.1” if the Waveform voltage is too
high. Although it is possible for these errors to
occur because of a temporary fault condition and
may be recoverable by cycling power, it generally
occurs because of a problem in the Excalibur Plus
PC circuitry and should be checked by the
Biomedical Department before returning the unit
to service.
3.3.11 Tone Monitor
A Tone Detector Shutdown circuit is provided to
shut down the RF output in the absence of the
audio tone, independent of the software function.
Dil and C73 half wave rectify the 16 Vdc tone
oscillator which is AC coupled through C71,
while D12 discharges C71 during the negative
half cycle. R68 and R69 divides the 16 Vdc to a
maximum of 11.76 Vdc to remain below the
maximum 12 Vdc input voltage to U26:11. R22,
R70 and U26:D form the comparator which will
enable/disable the gate outputs through U13:A
and B.
3.4 Controller Software
The behavior of the Controller is a function of
the custom program residing in the EPROM
memory (A3U1). Since U1 contains a custom
program, it must only be replaced with a suitably
programmed part. Most failures of this part may
be traced to mishandling, particularly due to stat-
ic discharge or to a secondary failure resulting
from application of excessive voltage to the cir-
cuit, as may occur if a voltage regulator fails.
However, since undetected failure of the EPROM
could escalate a minor failure to a serious conse-
quence in the O.R. environment, the program is
equipped with many fail detection and shutdown
features. Further, an independent external circuit
(the Watchdog Timer) guards against a malfunc-
tioning EPROM or CPU operation. This safety
system is discussed in the following overview of
the program.
3.4.1. Software Initialization and Test
Functions
The following list of software functions begins at
Power On Reset or by a manual reset performed
by an internal CAL/RST/RUN switch. The fol-
lowing initialization sequence must be successful-
ly executed before the main working program can
be entered.
1. Initialize outputs to relays and indicators.
2. Initialize all data memory locations for the
working program.
3. Verify that the Watchdog Timer is functioning
correctly and that it can control RF shutdown.
4. Verify that the RF current circuitry is operat-
ing.
5. Verify that no shorts exist in the hand/foot
controls.
6. Verify that no shorts exist in the membrane
panel.
7. Verify that internal data memory input/output
lines function properly and without crosstalk
using a walking bit test.
8. Verify that the contents of program memory in
all locations where the program resides is intact
using a 16 bit CRC (Cyclic Redundancy Check).
9. Verify that the contents of the calibration
memory (NOVRAM) in all locations where data
resides is intact using a 16 bit CRC (Cyclic
Redundancy Check).
10. Perform Display and Tone tests.
11. Enable RF output relays and pass control to
the working program.