Stanford Research Systems RGA100, Operating Manual And Programming Reference

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6-52 Scan and Measurement Commands
SRS Residual Gas Analyzer
is halted and the transmit buffer is flushed ( all remaining data is lost ). The
stopping command is executed after the scan is stopped.
SC0 : Commonly used to interrupt continuous scanning mode.
SCparam, param: 1 - 255: Multiple scans.The number of scans specified by
the parameter is executed. Scanning is immediately stopped when a new
command is received as in the case of continuous scanning.
SC* : The default parameter value is used for multiple scan excecution.
Default parameter value: 1 (single scan)
Error checking :
Number parameters must be integers and within the specified range.
No query format is allowed for the parameter.
Programming Tips:
x
Any command received by the RGA while scanning will immediately stop
the scan process and clear the RGA’’s transmit buffer. Remember to also clear
the computer’’s receive buffer to reset the communications. The new
command which stopped the scan will be excecuted.
x
The RGA has the ability to store a complete scan in its output buffer. The
scan remains in memory until all the data is transmitted out to the host
computer over RS232. As a result of the high acquisition rate of the RGA
there might be a delay between the time at which the data is collected and the
time at which a complete spectrum is displayed by the host computer. The
time lag between data acquisition and display depends on a large number of
factors including the scan rate (NF setting) of the RGA, the host computer’’s
processing speed, and the amount of handshaking activity over the RS232
lines.
x
Before a new scan starts the RGA checks its internal memory to make sure
that no data from any previous scan is pending to be transmitted. If data is
still pending, the RGA must finish transmitting it before the new scan can
start. This process may result in a delay from the time the scan trigger is
received to the time it actually starts. Using the SC1 command and waiting
until the whole scan data stream is transmitted back to the host computer will
minimize the problems that are associated to this feature.
x
Perform a complete Peak Tuning procedure on the RGA Head if the peaks
in the spectrum do not appear at their correct mass values (See Peak Tuning
section in the RGA Tuning chapter).
TP?, TP0, TP1
Description : Total Pressure Measurement .
Echo: Measured Ion Current.