Stanford Research Systems SR844 User Manual page 117

Display and Output Commands
DDEF(?)ch{,q}
DRAT(?){i}
FPOP(?)ch{,i}
DOFF(?)
ch,q{,x}
Many of the commands in this section use the parameters ch for Channel and q for
Quantity as specified in the following table.
Channel 1 (ch=1)
q display
0 X
1 R [Volts rms]
2 R [dBm]
3 X noise
4 AUX IN 1
The DDEF command selects the CH1 and CH2 displays. The parameter ch selects
Channel 1 or Channel 2 and is required. The DDEF ch, q command sets display
ch to quantity q as listed above.
The DRAT command sets or queries the instrument ratio mode. The signal may be
divided by either of the Aux Inputs. This scaling is applied before the Time
Constant filters and applies to X, Y, R, Xnoise and Ynoise.
The DRAT i command sets the ratio mode as listed below.
i Ratio
0 none
÷ AUX IN 1
1
÷ AUX IN 2
2
The FPOP command sets or queries the front panel (CH1 and CH2) output sources.
The parameter ch selects Channel 1 or Channel 2 and is required. The FPOP
ch,i command sets the analog output ch to quantity i as shown below.
Channel 1 (ch=1)
i output quantity
0 CH1 display
1 X
The DOFF command sets or queries the Offset for the quantity specified by ch,q
in the table below. The offset x is specified in % of full scale. The allowed ranges
for x are specified in the table below.
ch,q quantity
1,0
X
1,1
R[V]
1,2
R[dBm]
2,0
Y
Display and Output 4-15
q
0
1
2
3
4
Channel 2 (ch=2)
i output quantity
0 CH2 display
1 Y
x unit
–110 to +110 % of full scale
–110 to +110 % of full scale
–110 to +110 % of 200 dBm
–110 to +110 % of full scale
SR844 RF Lock-In Amplifier
Channel 2 (ch=2)
display
Y
θ
Y noise [Volts]
Y noise [dBm]
AUX IN 2