HP 8508A - Page 63

°
|
Operation
ss
SYSTEMS
Register Bit Coding
The
Status
Byte,
SESR,
Operation
Status
Re
‘ster
and
Transition
Filters
are
set
using
a
value
which
determines
the
conditions
to
be
enabled.
The
weights
of
each
of
the
bits
to
be
enabled
are
summed
to
obtain
the
value
required.
Table
3-1
shows
the
weighting
of
each
bit
for
each
of
the
registers.
Table
3-1.
Register
Bit
Coding
Bit
7
6
5
4
3 2
Weight
128
64
32
16
&
4
2
1
HP-IB
Response
Formats
Results
returned
by
the
HP
8508A
from
measurement
queries
take
the
ASCII
form:
<+>|<->D.DDDE<+>
|<->DD<term>
That
is
a
leading
sign,
a
four
digit
mantissa
between
1.000
and
9.999,
an
exponent
designator
“E”
or
“e”,
an
exponent
sign,
a
two
digit
exponent
between
00
and
99
and
a
terminator.
The
value
is
always
in
fundamental
units
(volts,
ohms,
watts,
dB
etc.).
The
terminator
<term>
depends
on
the
data
requested,
as
follows:
<term>
is
a
comma
(,)
where
another
data
item
follows
as
part
of
the
same
result.
<term>
is
a
semicolon
(;)
where
the
data
item
completes
a
result
and
another
result
follows.
<term>
is
linefeed
<If>
with
EOI
set
true
where
the
data
item
is
the
last
or
only
part
of
a
result.
Using
the
SYSTem:FORMat
command
results
can
also
be
coded
as
64
bit
Floating
Point
numbers,
in
IEEE488.2
Definite
Length
Arbitrary
Block
Response
Data
format.
This
will
be
of
the
form
ASCII
characters
‘#’
‘1’
8’
followed
by
eight
data
bytes
in
IEEE
754-1985
double
precision
format.
E1089
3-39