VersaPulse Select - Software

THEORY OF OPERATION
4-29
Versapulse Select Service Manual
0621-499-01 01/94
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4.7 SOFTWARE
There are two microprocessors in the VersaPulse Select: the main processor (Mµp) and the Safety Processor
(Sµp). Each has its own software program. The two programs are not identical, but are interdependant, i.e.,
the software continually requires confirmation/agreement from the other processing system in order to
continue its normal operating sequence. The two software programs are written to require checks with the
other processing system throughout normal operation to confirm that the two systems are in agreement
concerning operating parameters, system status, etc.. When either system fails to receive the expected
communication with the other system, a fault condition occurs and the laser is inhibited from firing. Both
processors have the ability to terminate a laser exposure. Communication is carried out through the DPRAM.
The following software sequence lists describe the operating sequence from the perspective of the main
processer. The safety processor has a similar start up sequence, then monitors system operation, acting to
inhibit laser firing if an abnormal operating condition is detected.
START UP & SELF TEST (main proccessor)
(Refer to the software table on 8-30)
AUTO CAL
The system performs a two point calibration for each channel to determine the relation between
flashlamp voltage and pulse energy. The cap voltage values for the minimum and maximum pulse
energy (.5 and 2.8) are determined, then the required voltages for other energies are derived. This is
the calibration data stored in NVRAM. The values found for each channel min and max pulse energy
are displayed on the second service screen.
IDLE LOOP
Check shutter position, power supplies, HVPS voltage and status, coolant, delivery fiber, BRH
connector status.
Check the service switch
Check for activation of any control
Check for exit to firing routine
Go back to start
FIRING
When the footswitch is pressed the main proccessor calculates the appropriate flashlamp voltage
using the selected pulse rate and energy to index the energy-vs-voltage curve stored in NVRAM (the
calibration data). Before each fire pulse the main processor moves the servo mirror, charges the
flashlamp capacitor and directs the firepulse to the appropriate flashlamp.
The fire pulse is triggered by the main processor, but the actual pulse is provided by a hardware
timer. The fire pulse discharges the capacitor through the selected flashlamp, interrupts both proces-
sors, and starts a hardware timer that enables the energy monitors. After the pulse, both processors
read the energy monitor signals.
Flashlamp voltage is adjusted according to the energy of the previous pulses, using a set of
mathamatical formulas that generate a correction factor. This is the light feedback function.
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