Keithley 237

+
87
86
0/1
0/1
128
64
1
=
SRQ
by 236/237/23
(Serial
Poll
1
=
Compliance
.~
Byte
Only)
1
=Error
1
=Ready
for
Trigger
85
84
83
82
0/1 0/1 0/1 0/1
32 16
8
4
Figure3-5.
SRQ Mask and
Serial
Poll
Byte Fonnat
Serial
Poll
Byte
81
80
0/1
0/1
2
1
L:
SECTION3
IEEE-488
Reference
1
=Warning
1
= Sweep Done
1 = Trigger
Out
1
= Reading Done
The general format of the serial poll byte
is
shown
in
Figure 3-5. Note that all bits ex-
cept for
bit
6 correspond to the bits
in
the
SRQ
mask. These bits flag the following
conditions:
Bit
0
(Warning)-
Set
when
one of the following warnings has occurred:
•
The
unit
is
uncalibrated.
•
Calibration
mode
entered
with
CAL
LOCK
switch
in
LOCKED
position.
•
Programmed value
is
out
of range (greater
than
that
allowed
by
range,
or
step
value is less
than
range resolution).
•
The sweep buffer has been filled
with
source
and
delay values.
• Attempted to
append
or
modify a non-existing sweep.
•
Specified pulse times cannot
be
met.
•
The instrument
was
programmed
when
not
in
remote.
•
Programmed source
and
compliance ranges
are
1.1kV
and
100mA
(237),
or
110V
and
1A (238).
• A measurement overflow has occurred,
or
a sweep has aborted.
• Unit
triggered while processing a previous command.
This
bit
is
cleared
when
the
U9 status
word
is
read
to determine the type of warning
(see
paragraph
3.6.19).
Bit 1
(Sweep
Done)-
Set
when
a sweep has completed. Cleared
when
a
new
sweep
is
triggered, a sweep
is
appended,
or
a
new
sweep is created.
Bit 2 (Trigger
Out)-
Set
when
the
unit
sends a trigger
out
pulse, including
at
the
end
of
a sweep. Cleared
on
serial poll
with
SRQ
asserted, reprogramming of
source/
measure controller (i.e.,
with
an
A,
B,
C,
F,
J,
L,
N,
0,
P,
Q,
S,
T,
V,
W command),
or
execution of
theM
command.
Bit 3 (Reading Done) - Set
when
a measurement has completed. Cleared
on
reprogramming of
source/measure
controller (i.e.,
with
an
A,
B,
C,
F,
J,
L,
N,
0,
P,
Q,
S,
T,
V,
W command),
or
a read of measurement over the bus.
+
3-41