Gain And Time Constant Commands - Stanford Research Systems SR844 User Manual

Gain and Time Constant Commands

SENS (?) {i}
AGAN
CRSV(?){i}
ACRS
OFLT(?){i}
OFSL(?){i}
The SENS command sets or queries the Sensitivity. The parameter i selects a
sensitivity from the table below.
i Sensitivity
0 100 nVrms / -127 dBm
1 300 nVrms / -117 dBm
µ
2 1 Vrms / -107 dBm
µ
3 3 Vrms / -97 dBm
µ
4 10 Vrms / -87 dBm
µ
5 30 Vrms / -77 dBm
µ
6 100 Vrms / -67 dBm
µ
7 300 Vrms / -57 dBm
The AGAN command performs the Auto Sensitivity function. This command is the
same as pressing Shift–SensUp. AGAN automatically sets the Sensitivity of the
instrument.
This function may take some time if the time constant is long. This function does
nothing if the time constant is greater than 1 s. Check the Interface Ready bit (bit
1) in the Serial Poll Status to determine when the command is finished.
The CRSV command sets or queries the Close Dynamic Reserve Mode. The
parameter i selects High Reserve (i=0), Normal (i=1), or Low Noise (minimum
close reserve) (i=2).
The ACRS command performs the Auto Close Reserve function. This command is
the same as pressing Shift–CloseResrv.
The OFLT command sets or queries the time constant. The parameter i selects a
time constant below.
i time constant
µ
0 100 s
µ
1 300 s
2 1 ms
3 3 ms
4 10 ms
5 30 ms
6 100 ms
7 300 ms
8 1 s
The OFSL command sets or queries the Time Constant Filter Slope. The
parameter i selects 6 dB/oct (i=1), 12dB/oct (i=2), 18dB/oct (i=3), or
24 dB/oct (i=4). This command also sets the No Filter mode, with parameter
i=0.
Gain and Time Constant 4-13
i Sensitivity
8 1 mVrms / -47 dBm
9 3 mVrms / -37 dBm
10 10 mVrms / -27 dBm
11 30 mVrms / -17 dBm
12 100 mVrms / -7 dBm
13 300 mVrms / +3 dBm
14 1 Vrms / +13 dBm
i time constant
9 3 s
10 10 s
11 30 s
12 100 s
13 300 s
14 1 ks
15 3 ks
16 10 ks
17 30 ks
SR844 RF Lock-In Amplifier