Stanford Research Systems SR830, Manual

Page: 87 / 177

5-4
Remote Programming
REFERENCE and PHASE COMMANDS
PHAS (?) {x} The PHAS command sets or queries the reference phase shift. The
parameter x is the phase (real number of degrees). The PHAS x com-
mand will set the phase shift to x. The value of x will be rounded to 0.01°.
The phase may be programmed from -360.00
≤
x
≤
729.99 and will be
wrapped around at ±180°. For example, the PHAS 541.0 command will
set the phase to -179.00° (541-360=181=-179). The PHAS? queries the
phase shift.
FMOD (?) {i} The FMOD command sets or queries the reference source. The parame-
ter i selects internal (i=1) or external (i=0).
FREQ (?) {f} The FREQ command sets or queries the reference frequency. The
FREQ? query command will return the reference frequency (in internal or
external mode).
The FREQ f command sets the frequency of the internal oscillator. This
command is allowed only if the reference source is internal. The parame-
ter f is a frequency (real number of Hz). The value of f will be rounded to
5 digits or 0.0001 Hz, whichever is greater. The value of f is limited to
0.001
≤
f
≤
102000. If the harmonic number is greater than 1, then the
frequency is limited to nxf
≤
102 kHz where n is the harmonic number.
RSLP (?) {i} The RSLP command sets or queries the reference trigger when using the
external reference mode. The parameter i selects sine zero crossing
(i=0), TTL rising edge (i=1), , or TTL falling edge (i=2). At frequencies
below 1 Hz, the a TTL reference must be used.
HARM (?) {i} The HARM command sets or queries the detection harmonic. This
parameter is an integer from 1 to 19999. 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 by ixf
≤
102 kHz. If the value of i requires a detection
frequency greater than 102 kHz, then the harmonic number will be set to
the largest value of i such that ixf
≤
102 kHz.
SLVL (?) {x} The SLVL command sets or queries the amplitude of the sine output.
The parameter x is a voltage (real number of Volts). The value of x will
be rounded to 0.002V. The value of x is limited to 0.004
≤
x
≤
5.000.