Stanford Research Systems SR844, User Manual

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Aux Outputs and Inputs 1-19
SR844 RF Lock-In Amplifier
Aux Outputs and Inputs
This measurement is designed to illustrate the use of the Aux Outputs and Inputs on the rear panel. You
will need BNC cables and a digital voltmeter (DVM).
Specifically, you will set the Aux Output voltages and measure them with the DVM. These outputs will
then be connected to the Aux Inputs to simulate external DC voltages which the lock-in can measure.
1 Press
Shift
then
Recall
to restore factory
presets.
This restores the SR844 to its factory presets.
2 Connect AUX OUT 1 on the rear panel to the
DVM. Set the DVM to read DC Volts, either
auto-ranging or on the 20 Vdc scale. The Aux Outputs can provide programmable DC
voltages between –10.5 and 10.5 Volts. The outputs
may be set from the front panel, or via the computer
interface.
3 Press
AuxOut
once or until the Reference
Display shows the level of AUX OUT 1, as
shown by the
AxOut1
indicator beneath the
display.
Show the level of AUX OUT 1 on the Reference
display. The default value is 0.000 V.
4 Use the knob to adjust the level to 10.000 V. Change the output to 10 V. The DVM should read
very close to 10.000 V.
5 Use the
knob
to adjust the level to –5.000 V. Change the output to –5 V. The DVM should read
very close to –5.000 V.
The auxiliary outputs are useful for controlling other
parameters in an experiment, such as pressure,
temperature, wavelength, etc. The AuxOut voltages
may be set remotely over the GPIB or RS-232
interface.
6 Press CH1
Display
four times or until
AUX IN 1
is selected.
Pressing
Display
cycles the CH1 Display through
the five available quantities. AUX IN 1 shows the
voltage at AUX IN 1. The two Aux inputs can each
read an analog voltage in the
±
10.5 V range. These
inputs may be used for monitoring and measuring
other parameters in an experiment, such as pressure,
temperature, position, etc. The Aux In voltages may
be read remotely over the GPIB or RS-232
interface.
7 Disconnect AUX OUT 1 from the DVM. We will use AUX OUT 1 to provide an analog
voltage to measure.
8 Connect AUX OUT 1 to AUX IN 1 on the
rear panel. The CH1 display shows the voltage at AUX IN 1
(close to -5.000 V).