Keithley 237

+
SECTION3
IEEE-488
Reference
a.&.24
Z
- Suppress
Purpose
Format
Parameters
Default
Description
Programming
Notes
Programming
Example
To
enable/
disable the suppression of subsequent readings
with
the present meas-
urement.
Zn
zo
Z1
Disable suppression
Enable suppression
Upon
power-up,
or
after receiving a
OCL, SOC,
or
JOX
command, the instrument de-
faults to
ZO
(suppression disabled).
Suppression allows a stored value to
be
subtracted from subsequent readings. When
suppression is enabled (Z1), the next conversion taken
in
OPERATE
will
be inter-
nally stored as a baseline. All subsequent readings
will
be
the difference between the
stored baseline level
and
the actual level.
1.
After enabling suppression, check the reading
done
bit
in
the serial poll byte to
verify
that
the S-D-M cycle for the baseline value has completed.
If
this
is
not
done,
and
the source value is changed before the baseline measurement,
an
unex-
pected suppression value
will
be
in
effect.
2.
It
is
not
necessary to disable suppression before re-enabling it. Hence, multiple
Z1
commands can
be
sent to
renew
the baseline measurement.
3.
Measurements
are
stored as unsuppressed values.
If
enabled, suppression is ap-
plied
when
data
is being
output
by
the instrument. Suppressed measurements
are flagged
in
output
data
(see
paragraph
3.6.6).
4.
Setting
a range lower
than
the stored baseline value will overrange the reading
if
you
go
into compliance.
5.
If
the stored baseline value is +5V
on
the
11
V range of a 236/237, a measured volt-
age of
+6V
or
more
would
put
the instrument
in
compliance.
6.
The present suppression value can
be
read
with
the U6 command.
7.
The baseline value maintains its value regardless of range. For example,
if
a
O.SV
measured reading is suppressed
on
the
1.1
V
or
1.5V (Model238) range,
it
will
re-
mainatO.SVon
the 11V, 15V (Model238),
110V,
and
1100V
(Model237) ranges.
8.
A suppressed value is
not
saved for
both
the voltage source
and
the current
source. The respective baseline will
be
lost
when
the sources are toggled.
OUTPUT
716;
"Z1X"
OUTPUT716;
"ZOX"
+
!
Enable suppression.
!
Disable suppression.
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