Stanford Research Systems SR865 Operation Manual page 41

Chapter 1
11. Touch {9}{0}{Enter} to set the offset to 90%.
12. Press the <CH1 Offset> knob briefly once to
turn the X offset off.
Press it again to turn it back on.
13. Press [CH1 Expand] once to select ×10.
Getting Started
percentage of the Sensitivity up to 999% (10×).
Offsets are useful for making relative
measurements.
Offsets can also be set using the keypad or
<Offset> knob.
The offset affects the value of X and any
outputs or displays of X. The DVM voltage
should be zero in this case.
The Offset indicator turns on next to the <CH1
Offset> knob. The X display on the screen has
an 'Ofst' indication that the displayed quantity
is affected by an offset. In this case, the bar
graph and numeric value are both zero.
The X output (10 mV) is now 10% of the
sensitivity (100 mV). The bar graph is at 10%
and the DVM reads 1 V.
Notice that the trace of X (green) is a line
10 mV above zero (center). This is because the
offset affects the value of X (unlike the
sensitivity).
The offset for CH1 can be turned on and off
without changing the offset value. Notice how
the trace of X changes when the offset is turned
off.
Leave the X offset on for now.
Expand ×10 effectively decreases the sensitivity
by 10 after the offset is applied.

X
=   −
CH1 Offset

Sensitivit y
Now, X = 100 mV, Sensitivity = 100 mV, the
offset is 90% and the expand is ×10. Thus the
DVM reads 10 V.
The X bar graph is now at 100% and the
numeric readout has added resolution. The X
display has an 'Expd' indication that the
displayed quantity is affected by a non-unity
expand.
Expand increases the resolution of the X
display and CH1 output. Note that the trace of
X is unaffected by expand. This is because
expand does not change the value of X.
SR865 DSP Lock-in Amplifier
23

  × ×
Expand 10V
