Stanford Research Systems RGA100, Operating Manual And Programming Reference

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Tuning Commands 6-67
SRS Residual Gas Analyzer
This parameter is protected by an internal calibration jumper (JP100) and a Protection-
violation error will result if the jumper is in the Calibration Disabled mode (see CE
command).
RSparam, param: 600.0000 - 1600.0000, *, ?, none
Description : RF_Driver output @ 128 amu (Peak Position Tuning command).
JP100 Jumper protected.
Echo: Query Response.
Warning: Please read the Peak Tuning Section of the RGA Tuning Chapter before using
this command.
Program the output of the RF_Driver @ 128 amu during a Peak Posion Tuning
Procedure. The parameter (one of four peak tuning parameters) represents the voltage
output selected for the RF_Driver @ 128 amu, in mV.
The magnitude of the RF determines the mass-to-charge ratio of the ions that can pass
through a quadrupole mass filter without striking the rods (i.e with stable oscillations). A
linear relationship between mass and RF amplitude is one of the most attractive features
of these type of filters.
The regulated output of the RF source that powers the RGA’’s quadrupole rods is
controlled by, and linearly related to, the voltage output of an RF_Driver circuit. Clearly,
a linear relation exists between the output of the RF_Driver, the RF amplitude on the
rods, and the mass setting of the filter. The purpose of a Peak Position Tuning Procedure
is to determine the voltages that the RF Driver must output at 0 and 128 amu so that all
the peaks in an analog spectrum appear in the right position. The RS command is used to
program the voltage output of the RF_Driver @ 128 amu during the Peak Position
Tuning Procedure. The value is saved in the non-volatile memory of the RGA Head and
used by the firmware to generate the internal scan parameters used to step the RF during
scans and single mass measurements .
Note to Supervisors : A calibration disable jumper (JP100) available on the circuit board
can be used by a supervisor to block any attempt to modify the value of the DI parameter.
Supervisors may use this feature to prevent accidental changes in the calibration
parameters by inexperienced operators. Setting JP100 will disable peak tuning of the
Head.
Parameters :
RSparam, param: 600.0000 - 1600.0000: If Calibration is enabled by the JP100
jumper (See CE Command), the parameter is saved into the non-volatile memory of the
RGA Head and the internal scan parameters used to step the RF during scans and single
mass measurements are updated accordingly.
RS* : Use this format to replace the peak tuning parameter with the original factory
setting for the RF_Driver output @ 128 amu. The factory value is retrieved from
memory, and used as the new parameter value to excecute the command as above.
RS? : Query. Returns over RS232 the parameter value currently saved in memory.