Reference And Phase Commands - Stanford Research Systems SR124 Operation And Service Manual

4.4 Commands

4.4.4 Reference and phase commands

PHAS(?) f
Example:
QUAD(?) z
Example:
FMOD(?) z
Example:
FREQ(?) f
Example:
SR124 Analog Lock-In Amplifier
Reference phase
Set (query) the reference phase shift to f , in degrees. Phase must be
in the range 0 f 360. The default value is PHAS 0.00.
PHAS 30.25
Phase quadrant
Set (query) the phase quadrant to quadrant z (I 1, II 2, III 3, IV
4) . Note that quadrants tokens are Roman numerals.
The quadrants are defined so that QUAD I corresponding to 0
90 , QUAD II to 90
Commanding a new value of QUAD adds or subtracts multiples of 90
to the current PHAS setting to bring the phase into the commanded
quadrant.
PHAS 105.25
QUAD?
2
Reference mode
Set (query) the reference mode to z (EXT1F 0, INTERNAL 1, EXT2F
2, EXT3F 3, RVCO 4) .
FMOD INTERNAL
Reference oscillator frequency
Set (query) the reference oscillator frequency to f , in hertz. The
default value is FREQ 1000.00.
The set form of the command is only allowed when the oscillator
mode is FMOD INTERNAL. The parameter f must be in the range de-
fined by by the FRNG command. Queries while in FMOD INTERNAL
mode return the commanded oscillator frequency.
Queries in either external or rear-VCO modes return the most re-
cently measured value of the oscillator frequency. Note that the
FREQ? query itself does not initiate a new measurement of the oscil-
lator frequency. That action is performed with the AREF command.
FREQ?
137.036000000
180 , and so on.
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