Output; Switching - Datron 4708 User Handbook Manual

OUTPUT
Switching
OUTPUT
ON/OFF
The 4708
should normally
be
connected
and
set
up
with
its
output
off.
This
isolates
the I+,
I-,
Hi
and
Lo
terminals
from
their internal circuitry
regardless of
RANGE, FUNCTION,
FREQUENCY
or
MODE
selections.
The
OUTPUT
OFF
LED
is lit
Pressing the
OUTPUT
ON
key connects the I+,
I-,
Hi
and
Lo
terminals to their
energized
internal
circuits.
OUTPUT OFF
Default
Certain instrument
states
are prohibited,
and
some
transfers
between
states are restricted
by program
firmware.
For
safety
reasons
some
of
these transfers result in
the
output being
switched
off.
Refer
to
Section
4,
Operating Routines.
OUTPUT ON
-
+
On
DC
Voltage or Current, the
polarity at the
Output
terminals
is
determined
by
the
Key
used
to
switch the output on, as
labelled.
In addition, polarity
may
be
reversed
by
using the
t
keys
to step the
output across zero value.
The
ON
LEDs
describe
the polarity
AT THE OUTPUT
TERMINALS,
not
on
the
OUTPUT
display. (In
''error"
and
"offset"
modes
these
two
could be
opposite).
In
AC
Voltage,
AC
Current
and
Resistance functions, the
ON
+
key
will
cause
the selected
outputs
to
appear
at
the output
terminals.
The
ON
-
key
will
cause
the error
buzzer
to
sound
and
Error
8
to
appear
in the
MODE/FREQUENCY
display.
OUTPUT OFF
Trip
- Fail
5
Message
Under
certain
abnormal conditions
which might compromise
safety,
the
4708
output will
trip
off,
accompanied by a
FAIL
5
message on
the
MODE
display.
Control
is
removed from
the
front panel keys.
If
the
FAIL
5 message
is
present, there
is
no automatic recovery
from
the tripped
state
whether
internal
conditions
have
or
have
not returned
to
normal.
Reset
Key
The
Reset
Key
has
two
functions:
1
.
It
allows the user
to
reset the safety
trip to test
whether
conditions
have
returned
to
normal.
If
they have;
the
FAIL
message
will
disappear, the
previous instrument
state
will
be restored but with
OUTPUT
OFF,
and
front
panel control will
be
returned
to
the
user.
If
conditions are
still
abnormal
the
FAIL
state will per-
sist,
and
a further attempt
may
be
made
after
a
suitable
interval.
The
Reset
LED
is
inoperative except
in
'TEST'
mode.
2.
It
returns the
instrument
to
power-up
conditions
in all
cases except the following:
• Self-test
mode
•
FAIL
conditions
•
In
remote
control
mode
(where
it
is
inoperative).
Other
Messages
A
full list
of
4708 messages
appears in Section 4.
The
fault
conditions
which
generate Fail
messages
are
analyzed
in the
Calibration
and Servicing
Handbook.
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