Keithley 237

Programming
Notes
Programming
Example
+
SECTION3
IEEE-488
Reference
In
this
instance,
the
complete
measure
string
is
placed
in
the
Measure$ variable.
In
cases
where
numeric
input
is
required,
the
instrument
can
be
programmed
in
format
2
to
eliminate
the
prefix
and
suffix,
and
a single
measurement
can
be
placed directly
into
a
numeric
variable
as
shown
below:
ENTER
716;Measure
Source
and
Measure
Status
Conditions
Both
the
ASCII
and
binary
formats include
status
flags for
the
source
and
measure
values. These
are
shown
in
Figure 3-3
and
Figure 3-4
and
described below:
•
An
"overlimit''
or
"in
compliance"
in
ASCII
or
binary
format
occurs
when
the
measured
value
reaches
the
compliance leveL The source
value
that
is
returned
represents
the
programmed
value,
not
the
actual value.
The
measured
value
that
is
returned
represents
an
actual
measurement
taken
at
the
compliance level.
•
A
"suppressed
measurement''
in
ASCII
format
is
flagged
when
suppression
has
been
enabled
with
the
Z1
command.
(See
paragraph
3.6.24.)
The
value
that
is re-
turned
is
the
difference
between
the
actual
and
suppressed
readings.
1.
With
either
binary
transfer
mode,
the
controller
or
program
should
be
set
up
to
terminate
on
the
byte
count
or
detection
of
EOI.
2. Table
3-7lists
the
number
of
bytes
that
are
transmitted
for
the
various
data
for-
mats.
3.
As
the
data
is
transmitted
in
continuous
strings,
without
carriage
returns
or
line
feeds
between
buffer locations,
you
must
format
the
data
for display
or
printing
legibility
(shown
in
the
example program).
4. A time
value
of
zero
is
output
with
de
data.
5.
Sweep
data
can
be
requested
as
soon
as
the
sweep
is triggered.
The
data
will
be
sent
as
it
becomes available.
Using
this
method
to obtain
data,
rather
than
waiting
for
sweep
done, decreases
throughput
time.
6.
If
only
partial
sweep
data
is
obtained
with
one
line
per
talk,
the
G
command
should
be
sent
to
reset
the
buffer
pointer
to
the
first line,
even
if
a
new
sweep
has
been
triggered.
7.
Only
terminator
characters are
sent
if
sweep
data
is
requested
while
in
de,
or
de
data
is
requested
while
in
sweep.
8. De
measurements
are
output
only
once
per
source-delay-measure cycle.
If
output
requests
are
faster
than
the
reading
update
rate,
the
bus
is
held
off
until
the
read-
ing
is
available.
9. A
measurement
overflow
is
indicated
at
112.5%
of
full
scale range.
10
20
30
40
50
60
70
80
DIM
Source$[200]
REMOTE716
OUTPUT 716;"F0,1X"
OUTPUT 716;"Q1,0,5,1,2,0X"
OUTPUT 716;"G1,0,2X"
ENTER 716;Source$
PRINT Source$[1,22]
PRINT Source$[24,45]
+
!
Dimension
string
for source val-
ues
!
Set
for IEEE-488 communication
!
Source
V,
measure
I,
sweep
func-
tion
!
Linear
stair
sweep, six 1V steps,
11
V
or
15V
range,
no
delay
!
Request
source
data
in
ASCII
with
prefix
and
suffix
!
Get
data
from
unit
!
Print
source
data
3-33