Stanford Research Systems SR865A, Operation Manual

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24 Getting Started Chapter 1
SR865A DSP Lock-in Amplifier
14. Press [CH1 Expand] once to select ×100. The red output Overload LED lights and a
‘Scale’ overload is indicated in the X display.
This is because CH1 is trying to reach 100 V
(10 times the previous DVM reading). Since the
CH1 output is limited to 10 V, the output is
overloaded. This has no affect on the value of X
and the trace is unchanged. The bar graph and
displayed value are pinned however.
15. Press [CH1 Expand] once to turn off expand.
Press the <CH1 Offset> knob briefly once to
turn the X offset off.
The X display returns to 100 mV, 100% bar
graph and 10 V CH1 output. The X graph is a
line at 100 mV 2 divisions above center.
With offset and expand, the output voltage gain
and offset can be programmed to provide
control of feedback signals with the proper bias
and gain for a variety of situations.
Offsets add and subtract from the values of X,
Y and R.
Expand increases the resolution of the displays
and analog outputs but does not change the
values of X, Y and R.
16. Touch the green scale tile {X} to display its
scale palette.
Touch to auto scale the green X trace.
When using the strip chart graph exclusively,
there is no need to use offset or expand to zoom
in on the data. Simply auto scale the data
channel to graphically offset and expand the
chart data.
See the Outputs and Scales discussion in the
next chapter for more detailed information on
output scaling