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Model
436A
Table
3-3.
Hewlett-Packard
Interface
Bus
Input
Program
Codes
Function
Program
Codes
ASCII
DECIMAL
Range
Least sensitive
5
53
4
52
3
51
2
50
Most
sensitive
1 49
Auto
9
57
MODE
Watt
A 65
dB
(Rel)
B
66
dB
[Ref]
c
67
dBm
D
68
Sensor
auto-zero
z
90
CAL
FACTOR
Disable
(100%)
+
43
Enable (front-panel
-
45
switch setting)
Measurement
Rate
Hold
H 72
Trigger with set-
T 84
ling time
Trigger, immediate
I
73
Free Run
at
maxi-
R 82
mum rate
Free Run with set-
v
86
ling time
sired range as well as
for
selection
of
the
autorange
function.
3-26. Programming
the
Mode.
Remote
mode
pro-
gramming is similar
to
Local
mode
selection. The
sequence
shown
in Example 1 is
recommended
for
taking
dB (Rel) readings
from
a
dB
[Ref]
reference.
3-27. Programming
Auto-Zero.
The
Power
Meter is
remotely
zeroed
the
same way
it
is zeroed in local.
Example
2 shown on
the
next
page outlines
the
Operation
program
steps
that
should be
written.
Specific
examples are provided
later
in
this Section. (Refer
to
Tables 3-3
and
3-4
for
Power Meter
input
and
output
strings. Refer
to
controller
manual
for
programming syntax.)
3-28. Programming
Cal
Factor. While
the
setting
of
the
front
panel
CAL FACTOR
switch
cannot
be
remotely
changed,
the
programmer
does have a
choice.
If
CAL FACTOR
enable is programmed,
then
the
Power Meter uses
the
Cal
Factor
set
by
the
switch.
If
CAL FACTOR
Disable is
program-
med,
then
the
Power Meter uses a Cal
Factor
of
100%,
but
the
program can
correct
for cal
factor
by
computing
the
corrected
reading from
the
actual
reading and
the
cal
factor
(a
Cal
Factor
table
must
be
stored
in
an array).
·
3-29. Programming Measurement Rate.· A feature
that
is
only
available via
remote
programming is
selection
of
standby, triggered,
or
free running
op-
eration
of
the
Power Meter. (During Local
opera-
tion,
the
Power Meter is allowed
to
free
run
with
approximately
133
milliseconds allowed
for
set-
tling
time
between measurements.) The specific
re-
mote
triggering capabilities are:
a.
Hold
(H) - when
the
power
meter
is pro-
grammed
to
Hold,
it
is
inhibited
from taking
measurements
and
from
outputting
data. Thus,
it
is
set
to
a predetermined reference condition from
which
a measurement
can
be triggered synchron-
ously
to
some external event.
b. Trigger
Immediate
(I)
-
this
programming
command
directs
the
Power Meter
to
make
one
measurement
and
output
the
data
in
the
minimum
possible
time,
then
to
go
into
Hold until
the
next
triggering
command
is received.
It
does
not
allow
settling time
prior
to
the
measurement.
c.
Trigger with
Delay
(T)
-
this
trigger
com-
mand
is identical
to
the
trigger immediate
com-
mand
except
that
it
causes
the
Power Meter
to
execute
a settling-time delay subroutine before
taking
a measurement and
outputting
data.
EXAMPLE
1
(dB
Rel/dB
Ref)-----------------------------
1
{controller talk
and Power Meter
listen}, "CT"
Sets
reference at present RF input
level.
{controller talk
and Power Meter
listen}, "BT"
Takes first reading relative to
set
reference
{universal unlisten, controller listen
and Power Meter
talk},
{Variable
name}
Power
Meter outputs reading
to
controller
{controller talk
and Power Meter
listen},
"T"
Takes subsequent readings
{universal unlisten, controller listen and Power
Meter
talk},
{Variable
name}
Power
Meter outputs reading to controller
3-17
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