Stanford Research Systems SR830 Manual page 27

Aux Outputs and Inputs
6. Press [Channel 2 Display] to select AUX IN 3.
7. Connect Aux Out 1 to Aux In 3 on the rear
panel.
Change the Channel 2 display to measure Aux
Input 3.
Channel 2 should now display -5 V (Aux In 3).
The Channel 1 and 2 displays may be ratio'ed to
the Aux Input voltages. See the Basics section for
more about output scaling.
The displays may be stored in the internal data
buffers at a programmable sampling rate. This
allows storage of not only the lock-in outputs, X,Y,
R or θ, but also the values of the Aux Inputs. See
the Programming section for more details.
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