Stanford Research Systems SR844, User Manual

Page: 117 / 246

Display and Output 4-15
SR844 RF Lock-In Amplifier
Display and Output Commands
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) Channel 2 (ch=2)
q display q display
0 X 0 Y
1 R [Volts rms] 1
θ
2 R [dBm] 2 Y noise [Volts]
3 X noise 3 Y noise [dBm]
4 AUX IN 1 4 AUX IN 2
DDEF(?)ch{,q} 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.
DRAT(?){i}
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
1
÷
AUX IN 1
2
÷
AUX IN 2
FPOP(?)ch{,i}
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) Channel 2 (ch=2)
i output quantity i output quantity
0 CH1 display 0 CH2 display
1 X 1 Y
DOFF(?)
ch,q{,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 x unit
1,0
X –110 to +110 % of full scale
1,1
R[V] –110 to +110 % of full scale
1,2
R[dBm] –110 to +110 % of 200 dBm
2,0
Y –110 to +110 % of full scale