Datron 4708 User Handbook Manual page 57

Output
Resolution
The
output resolution
conforms
to
the following
number
of
Range
100|a
Im
lOm 100m
1
10 100 1000
DCV,
ACV
DCI,
ACI
10
100 Ik 10k 100k
Im 10m
100m
a
Range Code
Rl R2 R3 R4 R5 R6 R7 R8
Functions:
DC
Voltage
F0
4.5
5.5
6.5
7.5 7.5 7.5 7.5 7.5
AC
Voltage
FI
-
4.5 5.5 6.5 6.5 6.5 6.5 6.5
DC
Current
F2
6.5 6.5 6.5 6.5 6.5
- - -
AC
Current
F3
6.5
6.5
6.5 6.5 6.5
- - -
Resistance
F4)
and Local
)
4.5 5.5 6.5 7.5 7.5 7.5 7.5
7.5
Sense
S0)
Resistance
F4)
and
Remote
)
7.5 7.5 7.5 7.5 7.5 7.5 7.5 7.5
Sense SI)
Frequency
Display Value
(Auxiliary Register)
In
remote programming,
the incremental (t ^
)
method
of
setting the frequency
is
not
used. Instead,
each
auxiliary
register value
is
input
explicitly
by
Code H****
in
numeric,
scientific
or engineering
notation.
The
manual
frequency 'Store'
memories
cannot be
set
via the
bus,
although
their
contents can be read using
'V' codes.
Frequency
Resolution
Frequency
is
resolved
to
three significant
digits
(1%
to
lOOppm
accuracy).
On
the display
this
occupies four
digit spaces,
to
accommodate
the decimal
point.
If
the significance
is
greater
than
three
digits,
the value
is
truncated
and
the controller
is
informed by
SRQ
Status
byte
(see
SRQ
status byte formats
later
in
this
section).
Frequency and
Voltage Constraints
On
lOOV
and
lOOOV
output ranges, the
4708
will refuse
any
command
for
an output which
exceeds
the limits
defined
on
page
3-7.
The
controller
is
informed by 'Error 7'
SRQ
status
byte
(see
SRQ
status
byte formats
later in this section).
Spot Frequency
Selection
Codes
T1-T5
select the spot frequencies stored
in
SF1-SF5
non-
volatile
memories.
Sixty
unique
memory
locations exist.
Thirty
five are allocated
to the
seven
AC
Voltage output ranges
and twenty
five to the five
AC
Current
ranges: five for
each
range.
The
value of
the
frequeney
called
up by any
T
command
is
therefore
dependent on
the preselected
F
and
R
codes.
With
spot active,
sending a
new
R
code
selects
the correspond-
ing spot
frequency
in
the
new
range.
A
new F
code,
sent
to
change
function, cancels the
T
command:
the
4708
frequency
reverts
to
IkHz.
The
controller
is
able
to
command
an uncalibrated
spot.
The
'uncalibrated'
message
is
displayed
as in
manual
operation,
the
4708
frequency remaining
as previously
set.
But
in addition,
the
4708
generates
an
SRQ
to
notify the
controller.
Code
T0
cancels
any
earlier
spot frequency
selection:
the4708
frequency
reverts
to
IkHz.
N.B.
The
Spot Frequency
facility
is
included
to
provide
separate, ultra-accurately calibrated
points in the
4708
output
spectrum. Therefore, frequencies
set into the 'spot frequency'
memories
can only be
changed
during
the
Autocal
routine (See
Section
8).
Guard and Sense
These
are configured
into
Local or
Remote
by
G
or
S
codes
respectively:
G0
-
Local
Guard
G1
-
Remote Guard
50
-
Local Sense
(forced
when F2
or
F3
has
been
commanded
and
when
FO,
Rl,
R2,
R3
and
R4
or
FI
,
R2,
R3
and
R4
have been
commanded). Programs
for
2-wire
resis-
tance
in
F4.
51
-
Remote
Sense
(available
only
when FO
or
FI have been
selected together with R5,
R6,
R7
and
R8
or
when
F4
has been
selected
in
all
ranges).
Programs
for 4-
wire
resistance in
F4.
5-9