Stanford Research Systems RGA100, Operating Manual And Programming Reference

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Ionizer Control Commands 6-37
SRS Residual Gas Analyzer
Careful adjustment of the voltage results in optimum coupling of the ion beam
into the QMF and maximum sensitivity.
If the filament is emitting electrons at the time the command is invoked, the focus
voltage is immediately reprogrammed, while the ion energy, electron energy and
electron emission currents remain unaffected. If the filament is off, the new focus
voltage value is stored in memory for the next time the filament’’s emission is
activated.
Command excecution times vary depending on the pre-existing ionizer
conditions. The end of the command excecution is prompted to the host computer
sending out the STATUS byte over RS232.
Parameters:
VFparam, param: 0-150 : The parameter represents the magnitude of the focus
plate bias potential in Volts ( The actual bias voltage is negative ). The STATUS
byte is transmitted at the end of command execution.
VF* : The default Focus plate biasing Voltage value is used to excecute the
command. Default: 90 (V).
VF?: Query the focus plate biasing voltage setting.
Error checking:
Number parameters must be integers within the accepted range.
The absence of a parameter (i. e. VF) is treated as a bad-parameter error.