Stanford Research Systems SR865A, Operation Manual

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Chapter 4 Programming 133
SR865A DSP Lock-in Amplifier
The requested values are returned in a single string with the values separated by commas
and in the order in which they were requested. In this example, the returned string might
be
0.951359,0.0253297,1.234
The first value is X, the second is Y and the third is Aux In1.
Not all parameters are measured at the same rate within the SR865A. The external
frequency, for example, is only measured every reference period (at low frequencies).
The most recent measurements for these parameters are returned by
SNAP?
SNAPD?
The SNAPD? query returns the values of the 4 parameters presently displayed as Data 1
through Data 4, at a single instant. This is equivalent to the SNAP? command (described
above), with four parameters returned. The four values returned correspond to the
DAT1
(green),
DAT2
(blue),
DAT3
(yellow) and
DAT4
(orange) data channels.
The requested values are returned in a single string with the values separated by commas,
and in the order of the Data channel assignments. The assignment of measurable
parameters to the four Data channels can be controlled or queried by the
CDSP(?)
command.
Example
SNAPD? Returns the values of the four Data channels
After reset, the default assignment of the Data channels is X, Y, R, and θ. In this case,
the example may return a string such as:
2.3346669042e-09,4.3821726803e-10,2.4805799637e-09,19.749698639