Stanford Research Systems SR810 Manual page 67

Front Panel
Auto Setup
There is no truly reliable way to automatically setup a lock-in amplifier for
all possible input signals. In most cases, the following procedure should
setup the SR810 to measure the input signal.
1. Press [AUTO GAIN] to set the sensitivity.
2. Press [AUTO RESERVE].
3. Adjust the time constant and roll-off until there is no Time Constant
overload.
4. Press [AUTO PHASE] if desired.
5. Repeat if necessary.
At very low frequencies, the auto functions may not function properly.
This is because very low frequency signals overload very infrequently
and the time constants used tend to be very long.
4-19