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on the Coag Power level LEDs to indicate the
FAULT. See Appendix A.
3.5.2 CAL Mode
CAL Mode is used to gain access to and adjust
the calibration parameters contained in the CAL
NOVRAM, A3U2. CAL Mode also provides
access to Watchdog Timer and Pseudo Run Mode
diagnostics, which are provided to simplify trou-
bleshooting of faults which would otherwise leave
the unit inoperative due to fault detection during
RUN Mode.
3.5.2.1 CAL NOVRAM Contents
Power calibration tables are stored in the
NOVRAM for each mode of operation. During
RUN Mode, each table is entered with the pre-
sent power setting for the active mode, and the
table returns a drive value to be passed to the
VBASE Generator or Waveform Generator neces-
sary to produce the set power. Table values are
stored in 16-watt increments, and software per-
forms linear interpolation to find drive values for
intermediate power settings. During Power
Calibration, each table value is adjusted up or
down in steps of one when the power controls are
moved while the unit is activated; the adjusted
value is also driven out to the PA, causing output
current to vary accordingly. The adjustment range
for each entry is limited to +/-25% around a set
of Program ROM nominals determined during
product development.
When the unit is deactivated, the knobs are used
to select table entries, which are associated with a
"target current" display corresponding to the out-
put power for that entry. Target current values are
constants stored in Program ROM which have
been calculated taking the selected load resistance
option and characteristic load regulation into
account.
Each table entry can be declared Calibrated or
Uncalibrated. If the CAL NOVRAM CRC test
passes on CAL Mode entry, all points are declared
Calibrated; otherwise all are declared
Uncalibrated. After entry to a Power Cal Mode,
monopolar (CC) or Bipolar (bP), if any point is
adjusted, then all other points which have not yet
been selected and activated ("looked at") are
declared Uncalibrated. Uncalibrated points are
flagged by flashing target current displays.
Restoring a point to Calibrated status requires
only that it be looked at.
When Power Calibration is exited, software veri-
fies that all points are Calibrated; if any remain
Uncalibrated, a HLP 10 will be declared.
Monotonicity (HLP 11) checks verify that succes-
sively higher-power entries in each mode contain
successively higher PA drive values. If both of
these checks pass, the NOVRAM CRC will be
recalculated and stored. Otherwise, the CRC will
be intentionally scrambled, preventing further
operation (HLP 3) in RUN Mode. Cal Menu
selections containing Uncalibrated or Non-
monotonic entries will also flash.
The Cal NOVRAM also stores the VARM values
for 10 and 150 ohm Return Circuit resistances
provided during ARM Cal mode. The power
cal load resistance options are also stored so that
they need not be reselected each time.
3.5.2.2 CAL Mode Execution
Entry to and operation of CAL Mode is described
in Section 4.3.
CAL Mode firmware is executed from power up
or reset when A3S1 is set to CAL. If the PAD
button on the control panel is not pressed at this
time, the unit will terminate with a HLP 9 diag-
nostics code. This prevents a unit from being
accidentally miscalibrated if put clinical service
with A3S1 incorrectly set.
Initialization checks include program ROM CRC
and RAM tests; as in RUN mode, if these fail,
the unit will terminate with the appropriate HLP
code (See Appendix A). Power amplifier tests are
not performed so that Pseudo Run Diagnostics
(dI 2) may be entered to aid troubleshooting
faults which may cause this test to fail in RUN
mode. If the WDT tests fail, the program branch-
es directly to WDT Diagnostics (dI 1), since cali-
bration is not possible with a faulty WDT circuit.
The Cal NOVRAM CRC is tested; if that fails, a
set of nominal calibration settings are loaded into
the NOVRAM, and all cal points are declared
Uncalibrated (flashing).
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Troubleshooting
