2000 MS Hardware Maintenance
28
Functional Description
electronics service switch allows the vacuum to the maintained in the event that
the electronics need to be serviced.
The line voltage switches are located on the power board and the turbomolecular
controller. These switches are set at the factory.
The turbo controller regulates the speed of the turbo pump. The controller
provides turbo speed and startup power to the power board.
WARNING:
SHOCK HAZARD
In the event of an emergency, shut off all power to the Saturn GC/MS by placing
the main power switch in the OFF position.
Power Board
The power control board supplies power to all electronics components except the
turbomolecular controller. It controls the heaters, ion trap and ion gauge
filaments and solenoid valves.
NOTE: The switching power supply is protected by a 5A, Non-Time-Delay, fuse.
The following switching power supplies reside on the board:
•
The +5V dc power supply, which su5V dc voltage to all digital
circuits.
•
The -15V and +15V dc power supplies, which supply the voltages to the
analog circuits on the power board and the manifold electronics
assembly.
•
The +20V and -20V dc power supplies, which supply the voltages to the
SAP/Wave and RF generator board’s analog circuitry.
•
The +24 Vdc power supply supplies power for the solenoid valves,
electronics compartment fan and the electron multiplier power supply.
•
The +55 Vdc power supply, which supplies unreg55 Vdc voltage
to the RF generator board.
•
The 180-volt power supply that supplies voltage to the ion trap electron
gate circuit and the ion gauge.
The following circuits also reside on the board:
•
The trap and ion gauge filament control circuits, which provide current to
heat the filament and regulate the emission current from the filament.
You set the trap filament emission current between 5 and 100
µ
A via the
data system.
•
Three heater control circuits that provide feedback control for the
manifold, trap and transfer line heaters. The trap heater uses a
proportional integral (PI) control circuit. Because there is an integrator
component in this controller, removing power from the circuit will produce
a lengthy stabilization time, e.g., up to two hours (dependent on the
temperature set point).
•
Three solenoid control circuits, which turn the calibration gas, CI reagent
gas, and CI shutoff valve solenoids on and off.
