Varian 4000 GC, Hardware Operation Manual

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Various switched components in the system (such as solenoid valves) are
controlled through latches. Analog control voltages are set by the scan processor
through a set of digital to analog converters ranging in resolution from 10 bits for
lens voltages to 16 bits for the trapping field RF level.
A number of specialized functions are implemented on the controller using field
programmable gate arrays. (FPGAs). These functions include an acquisition
controller, waveform/memory controller, and RF scanning module.
Power Board
The power board supplies power to all electronic components except the
turbomolecular pump controller. It also controls a number of heaters and solenoid
valves as well as providing signal routing between the controller board and other
boards in the system.
NOTE: The switching power supply is protected by a 5A, Non-Time-Delay, fuse.
Switching power supplies are utilized for all voltages. The following switching
power supplies reside on the board:
•
A +5 Vdc power supply, which su5 Vdc voltage to all digital
circuits.
•
-15V and +15 Vdc power supplies, which supply the voltages to the
analog circuits on the power board and the manifold electronics
assembly.
•
+20V and -20 Vdc power supplies, which supply the voltages to the
Controller and RF generator board’s analog circuitry.
•
A +24 Vdc power supply which provides power for the solenoid valves,
heaters, the EFC, electronics compartment fan, and the electron
multiplier power supply.
•
A +60 Vdc power supply, which supplies unreg55 Vdc voltage to
the RF generator board.
•
The 200-volt power supply that supplies voltages to various lens circuits
and gate circuits as well as the ion gauge.
The following circuits also reside on the board:
•
Four heater control circuits that provide feedback control for the
manifold, trap, external source and transfer line heaters. The trap
heaters use proportional integral (PI) control circuits. Because there is an
integrator component in this controller, removing power from the circuit
may produce a lengthy stabilization time, e.g., up to two hours
(dependent on the temperature set point).
•
Four solenoid control circuits, which turn the calibration gas, CI reagent
gas, CI shutoff valve and EI/CI volume solenoids on and off.
•
The diagnostic multiplexer circuit, which routes the voltage output of
various components, and circuits on the power control board to the
Controller board. You can access these voltage outputs through the
diagnostic pages.
Mounted on the top edge of the power board are 15 monitor LEDs. When
illuminated, these lights indicate that the voltages of the various circuits on the
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