Veeco MPS-3000 CE, Technical Manual

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Chapter 6: Local Operation
Operating conditions may need to be maintained over time without user
attention. The MPS-3000 CE power supply incorporates a Local or Auto-
matic mode of operation. The internal microprocessor monitors and con-
trols several parameters including the accelerator-current-to-beam-current
ratio (A/B Ratio).
If the value exceeds the limit programmed into the A/B Ratio, an E25 error
message appears on the Accelerator Current display and a continuous
audio signal will be heard if the audio alarm is enabled.
MPS-3000 CE FC:
In Local mode, the internal microprocessor constantly monitors the
beam current and maintains it at the programmed value by making
adjustments to the cathode filament current. The microprocessor also
monitors the neutralizer emission current and adjusts the neutralizer
supply as required to keep the emission-current-to-beam-current ratio
at 125%. A 200% emission-to-beam-current ratio may be selected
through SW1-7 (refer to
“Controller Board Switch Definitions” on
page 20 ).
MPS-3000 CE HC:
In Local mode, the internal microprocessor constantly monitors the
beam current and maintains it at the programmed value by making
adjustments to the discharge current. The microprocessor also monitors
the hollow cathode neutralizer emission current to keep the emission-
current-to-beam-current ratio at 125%. A 200% emission-to-beam-
current ratio may be selected through SW1-7 (refer to
“Controller
Board Switch Definitions” on page 20 ).
MPS-3000 CE PBN:
In Local mode, the internal microprocessor constantly monitors the
beam current and maintains it at the programmed value by making
adjustments to the cathode filament current. The microprocessor also
monitors the plasma bridge neutralizer emission current and keeps the
emission-to-beam- current ratio at 125%. A 200% emission-to-beam-
current ratio may be selected through SW1-7 (refer to “Controller
Board Switch Definitions” on page 20 ).
In Local mode, stored values may be recalled from the memories. Use
the switches and Adjust knob on the front panel to make changes in
beam voltage, beam current, accelerator voltage, and A/B Ratio. No
changes may be made for any parameters in Cathode, HC, Discharge,
Neutralizer or HCN power supplies.