LUMENIS VersaPulse PowerSuite - 4.4.11 Low Energy Attenuator Circuit

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Closing switch SW4 on the Controller PCB provides the ground return path for the +5 VDC pullup, generating
a /SERVICE_ATTEN_SW/ input signal to the digital I/O EPLD U49-27. U49 will then output the following
signals:
• A /SATEN_H_DRV/ signal
• A /GATED_SATEN_DRV/ signal
The /SATEN_H_DRV/ signal will invert to turn on Q5 completing the current path, resulting in turning on the
first stage of Q3 for 100ms. This bypasses the current resistor R70 causing the solenoid to energize, moving the
attenuator into the beam path. U49 will also output a /GATED_SATEN_DRV/ signal, which gets inverted
turning on the second stage of Q3. After the 100ms timeout, Q5 turns off redirecting the current through R70,
across the service attenuator solenoid and then through Q3. The attenuator position is monitored by a slotted
optical switch U3. The /SERV_ATENIN/ line goes low when U3 is blocked and grounded when the switch is
not blocked. The signal becomes the input signal to U61 which gets inverted to S_ATEN_IN and becomes the
input signal to the microprocessor digital I/O EPLD on the Controller PCB.
4.4.11 Low Energy Attenuator Circuit
The Low Energy Attenuator Circuit inserts attenuation into the beam path to allow the VersaPulse PowerSuite
to provide treatment pulse energies lower than the minimum pulse energy available out of the cavity.
The micoprocessor asserts a low /ATTEN_H_DRV/ and /GATED_ATEN_DRV/ signals which becomes
inverted by U61. The high output signal from U61-4 is applied to the base of Q7. Q7 completes the ground
return path for the +24 VDC turning on the first stage of Q6 for 100ms. As Q6 turns on, the current flow
bypasses the current resistor R73 resulting in the turning on of the low energy attenautor solenoid and
inserting the low power attenuator into the beam path. At the same time Q7 is turned on, the inverted /
GATED_ATEN_DRV signal turns on the second stage of Q6 completing the current path for the low energy
attenuator solenoid. After the expiration of the 100ms, the first stage of Q6 turns off redirecting the current
flow across R73 and then through the second stage of Q6. The low energy attenuator is located on the Low
Energy Attenuator PCB.
The Low Energy Attenuator /ATTENIN/ is the output signal of the slotted optical switch U1 on the Low
energy Attenuator PCB.
When the switch is blocked, its sensed output is low. When the switch is not blocked its output signal is high.
The switch is blocked when the attenuator is energized, blocking the beam. The sensed line from U1 is sent
from the Low Energy Attenuator PCB to the Controller PCB, J27-4 to J12-4. When the solenoid is energized,
the low energy attenuator is in the beam path, U1 output is low. The low output is inverted to become
ATTENIN which becomes the input signal to the microprocessor by way of the Digital I/O EPLD U49-25. The
ATTENIN signal also illuminates LED24.