OPTIKON ASSISTANT - Sensors and Air Board 391120 Functionality

Assistant Service Manual
OPTIKON 2000
Code 121008S 6-23 Rev. D
6.3.2 SENSORS AND AIR BOARD 391120
The 391120 Sensors and Air board schematics have been logically divided in
two sheets:
Sheet 1/2:
This sheet contains:
- The circuitry of the pressure sensor (mounted on the board) used to
monitor the ASSISTANT input pressure. The balanced output of the
strain gauge sensor is voltage buffered by U1-A-B, then delivered to
the differential amplifier U1-C.
U1-D allows subtracting the fixed voltage generated by U3-D-C to
remove the offset, the trimmer R45 partitions the output of U1-D to
adjust the gain.
- The Amplifier of the vacuum sensor (mounted on the 369130 Vacuum
Signal filter) used to monitor the vacuum level in the aspiration line
(ACS3).
U3-B subtracts the fixed voltage generated by U3-A to allow offset
adjustment. The R50 trimmer is for gain adjustment.
Sheet 2/2:
This sheet contains the electronics needed for the low pressure air
tamponade system: U2-A subtracts the offset (regulated by the trimmer R49)
from the output of the low pressure sensor P2 (assembled on the board).
The trimmer R51 adjusts the gain, its output is buffered by U2-B.
The output of U2-B (TP4) is the actual pressure of air injection. It is delivered
to the Control Board (AIR_PRESSURE, J2-6)
And to U2-C to be compared with AIR_PRESET in order to adjust the speed
of the air pump (J1) to maintain Actual level equal to Preset level.
AIR_ENABLE allows the Control board to stop the air pump motor even in
case of fault of Q1.