Stanford Research Systems SR865A, Operation Manual

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Chapter 4 Programming 107
SR865A DSP Lock-in Amplifier
Example
FREQ 12.34E3 Set the internal frequency to 12.34 kHz
FREQ 12.34 KHZ
FREQ 12340
FREQ?
Returns the internal (or external) frequency in Hz
FREQINT(?) { f } { HZ | KHZ | MHZ }
The FREQINT f command sets the internal frequency to f. The value of f will be rounded
to 6 digits or 0.1 mHz, whichever is greater. The value of f is limited to 1 mHz ≤ f ≤
4 MHz.
The query form, FREQINT? , always returns the internal reference frequency.
Example
FREQINT 12.34E3 Set the internal frequency to 12.34 kHz
FREQINT 12.34 KHZ
FREQINT 12340
FREQINT?
Returns the internal frequency in Hz
FREQEXT?
The
FREQEXT?
query returns the external reference frequency.
Example
FREQEXT? Returns the external frequency in Hz
FREQDET?
The FREQDET? query returns the actual detection frequency. This is helpful in dual
reference mode or harmonic detection. Otherwise, the detection frequency is either the
internal or external reference frequency.
Example
FREQDET? Returns the detection frequency in Hz
HARM(?) { i }
The HARM i command will set the lock-in to detect at the i
th
harmonic of the reference
frequency. The value of i is limited to 1
≤
i
≤ 99.
Example
HARM 2 Set the harmonic detect to 2
HARM?
Returns the harmonic number i
HARMDUAL(?) { i }
The HARMDUAL i command will set the lock-in to detect at the i
th
harmonic of the
external frequency in dual reference mode . The value of i is limited to 1 ≤ i ≤ 99 . The
actual detection frequency, when operating in dual reference mode, is
ext HARMDUAL int HARM detect
f i f i f
u u