Stanford Research Systems SR865A, Operation Manual

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106 Programming Chapter 4
SR865A DSP Lock-in Amplifier
Reference Commands
TBMODE(?) { AUTO | INternal | i }
The TBMODE i command sets the external 10 MHz timebase mode to auto (i=0) or
internal (i=1).
Example
TBMODE AUTO Set the timebase mode to auto
TBMODE 0
TBMODE?
Returns the timebase mode i
TBSTAT?
The TBSTAT? query returns the current 10 MHz timebase source, either external (0) or
internal (1).
Example
TBSTAT? Returns the current 10 MHz timebase
PHAS(?) { p } { UDEG | MDEG | DEG | URAD | MRAD | RAD }
The PHAS p command sets the reference phase shift to p degrees. The value of p is set
with a resolution of ~0.0000001°. The phase may be programmed from
− 360000° ≤ p ≤ 360000° and will be wrapped around at ±180°. For example, the
PHAS 541.0 command will set t he phase to −179.00° (541− 360 = 181;
181−360
=
−
179). Phase may be specified in degrees (default), or millidegrees,
microdegrees, radians, milliradians, or microradians.
Example
PHAS 12.34 DEG Set the reference phase to 12.34 deg
PHAS 1.234E1
PHAS 12340 MDEG
PHAS?
Returns the reference phase in degrees
APHS
The APHS command performs the Auto Phase function. This command is the same as
pressing the [Auto Phase] key. The outputs will take many time constants to reach their
new values. Do not send the command again without waiting the appropriate amount of
time.
FREQ(?) { f } { HZ | KHZ | MHZ }
The
FREQ 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, FREQ? , returns the internal reference frequency whenever the reference
mode is either Internal, Dual, or Chop. The query returns the external frequency when
operating in External mode. This behavior mirrors the value displayed in the info bar at
the top of the display.