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136
Programming
CAPTURELEN(?) { n }
The
CAPTURELEN
buffer length in kilobytes (256 total data points). For example, 32 k points of X and Y is
a total of 64 k data points (256 kbytes of buffer at 4 bytes/point) and a length of n=256.
32 k points of X, Y, R and θ requires twice as much or a length of n=512.
Since the internal blocks that make up the buffer are 2 kbytes each, the value of n must be
even and is limited to 1 ≤ n ≤ 4096. If n is odd, then the buffer length will be set to n+1.
Example
CAPTURELEN 256
CAPTURELEN?
CAPTURECFG(?) { X | XY | RT | XYRT | i }
The
CAPTURECFG i
R and θ (i=2) or X, Y, R and θ (i=3).
For a given buffer length (total data points), capturing more parameters results in fewer
points of each parameter and a shorter total capture time. The capture rate is unaffected
by
CAPTURECFG.
Example
CAPTURECFG 1
CAPTURECFG XY
CAPTURECFG?
CAPTURERATEMAX?
The
CAPTURERATEMAX?
current time constant) in Hz. This is a query only command.
The actual capture rate can be this maximum rate or this rate divided by powers of 2.
Note that this maximum rate is dependent on the time constant and sync filter settings.
Example
CAPTURERATEMAX?
CAPTURERATE(?) { n }
The
CAPTURERATE n
n
2
. The value of n is limited to 0 ≤ n ≤ 20. Set n=0 for the maximum capture rate.
For example, if
the capture rate to (78125)/(2
modified during a capture, the sampling rate will change mid-capture.
SR865A DSP Lock-in Amplifier
command sets or queries the capture buffer length. The value n is the
Sets the capture buffer length to 256 kbytes or 64 k total data
points
Returns the buffer length n (kbytes)
command sets the capture configuration to X (i=0), X and Y (i=1),
Capture X and Y
Returns the capture configuration i
query returns the maximum allowed capture rate (at the
Returns the maximum capture rate in Hz
command sets the capture rate to the maximum rate divided by
CAPTURERATEMAX?
4
) = 4882.8125 Hz. Note that if the time constant is
returns 78125, then
CAPTURERATE 4
Chapter 4
will set
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