Pset Transfer; Power Adjustment; Setting Storage - ConMed Hyfrecator 2000 Service Manual

2000

3.3.4.1.3 PSET Transfer

During the 1 msec LED blanking period, the Control microcontroller turns both Q1 and Q2 off and
presents an 8-bit code, PSET, on the PSETO0:7 bus to the Monitor microcontroller. This transfer is
necessary because the Monitor microcontroller does not have direct access to user power adjustment inputs.
PSET contains data showing the current operating mode and power setting, as well as codes for invalid
VMODE voltage and Control-detected fault conditions. Certain ranges of PSET values are unused and
considered invalid.
The Monitor microcontroller uses PSET to set fault limits on HV , gate frequency and gate duty cycle, and to
validate VMODE. It also compares PSET to the power display data driven to the LEDs. If PSET presents
a Control-detected fault code, the Monitor microcontroller will initiate a fault detection shutdown and
display that code on the LEDs.

3.3.4.1.4 Power Adjustment

While the unit is idle, the operator may change the power setting either by turning the 36-step/revolution
incremental encoder, S2, or by pressing the remote Up/Down buttons on the accessory. The effect of the
adjustments appear immediately on the power LEDs and on PSET. Power adjustments can be made in the
smallest steps displayable in the mode: 1 watt, or in LO under 10 W , 0.1 W . Each step change using the
remote buttons is announced by an audible click from the tone generator; no sound is produced with
encoder adjustments.
Power cannot be decreased below zero or above the maximum setting for that mode. Encoder adjustments
are ignored if either remote button is depressed. Attempts to change power or mode while activated are
ignored.
Both adjustment methods feature a fast slew mode to expedite large power changes:
• If the encoder is rotated faster than about 1 revolution per second, the step size increases fivefold.
• If a remote adjust button is closed for over 600 msec, steps will occur at 5 per second for the next second
or until the button is released. If the button is held even longer, the step rate increases to 16 per second, and
step size doubles.

3.3.4.1.5 Setting Storage

Power setting data is stored separately in the Control microcontroller RAM for each Mode for immediate
retrieval if the Mode selection is changed. These settings are also copied to the Control EEPROM, U3, if
any power setting is changed. The EEPROM storage cycle is armed upon any power adjustment, and is
subsequently executed upon the earliest of three events: activation, mode change or 2.5 seconds elapsed with
no power adjustments. Settings for all three modes are stored in the same cycle.
The EEPROM contents are expected to remain intact with no power or batteries for at least 10 million write
cycles, well beyond the service life of the Hyfrecator® 2000.
The settings data is stored redundantly for error detection. On power-up, if the setting data has been
corrupted, all Last Settings will default to zero. This fault is not deemed serious enough to justify disabling
the unit. If the Control microcontroller is unable to access the EEPROM during an attempted settings
write, however, a fault will be declared to avoid unexpected high settings during the next power-up.
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