3.4
Commands
3 – 13
Shield
SHLD(?)
y
{
, z
}
Set (query) the preamplifier BNC shield connection for
y
=
(
INPUT 0
,
BIAS 1
)
{
to
z
=
(
GND 0
,
BIAS 1
,
FLOAT 2
,
PROG 3
)
}
.
The following combinations are valid:
BNC
y
Shield
z
INPUT
GND
BIAS
PROG
BIAS
GND
FLOAT
SHLD INPUT,BIAS
Example:
SHLD BIAS,FLOAT
Autozero
CHOP(?)
{
z
}
Set (query) the preamplifier autozero selection
{
to
z
=
(
OFF 0
,
ON 1
)
}
.
There will be a wait before the chosen regime takes e
ff
ect (Sec-
tion 1.2.2.1).
CHOP?
Example:
ON
Reference Clock Direction
SYNC(?)
{
z
}
Set (query) the direction of the signal at the SIM918 rear-panel
Ref Clock Sync connector
{
to
z
=
(
IN 0
,
OUT 1
)
}
. The direction is
reset to
IN
upon power-on.
SYNC 1
Example:
Reference Clock Frequency
FREQ?
Query the reference clock frequency of the preamplifier, in hertz.
The nominal frequency of the internal reference clock is 1.0 Hz. The
command can also be used to measure the frequency of an external
reference clock.
If autozero is o
ff
and the reference clock is internal, or if autozero is
o
ff
and
APLL
is set to
OFF
under external reference clock, there are no
reference clock transitions inside the SIM918 and
FREQ?
will time
out with Execution Error 16.
FREQ?
Example:
1.023
SIM918
Precision Current Preamplifier
Summary of Contents for SIM918
Page 4: ...ii Contents SIM918 Precision Current Preamplifier ...
Page 7: ...General Information v SIM918 Precision Current Preamplifier ...
Page 12: ...x General Information SIM918 Precision Current Preamplifier ...
Page 62: ...3 30 Remote Operation SIM918 Precision Current Preamplifier ...
Page 63: ...4 Circuit Description In This Chapter 4 1 Schematic Diagrams 4 2 4 1 ...
