Datron 4708 User Handbook Manual page 44

6.
Over-Voltage
Checks
The 4708
automatically
tests
the over-voltage detector
thresh-
old
levels in
Low
Voltage
state.
If
the
check
fails,
the
message
Fail 2 appears, otherwise
PASS
message
indicates both
tests
completed
successfully.
7.
The
Test
LED
goes OFF.
The
following
table
summarizes
the
MODE
display messages:
Message
Reason
SAFEtY
running
First
stage of
'test'
operative
PASS
No
failure
discovered.
FAIL
6 only
Parity error in Calibration
Memory
Check.
FAIL
2 only High
voltage
can be
present
in
Low
Voltage
state.
Any
combination of
these
two
FAIL
messages can
appear
in
sequence, replacing
the
running
message.
8.
To
terminate Test before
the Display
and
Key
checks,
press
any key
other than
Test:
4708
returns
to
prior conditions.
Display
and Key Checks
Visual
Check Sequence
Read
this
Note
before pressing Test
Key
to start
NOTE:
After pressing Test Key,
the Visual
Check
se-
quence commences. During
this
sequence ob-
serve
that:
(a)
No
display segments
or blocks are miss-
ing or incomplete.
(b)
Segments and
blocks
do
not appear
spuri-
ously.
(c)
Inter-digit
and
inter-segment 'streaming'
does
not occur.
(d)
All
LEDs
are
lit
in their correct sequence.
(e)
LEDs
are not
lit
spuriously.
Press Test key
-
Test
LED
lights
-
All other
LEDs
unlit
-
Displays
cleared
momentarily.
then:
2.
MODE
Display
(a) Initial presentation:
r
are displayed
segment by
segment.
N.B.
Commas
are presented
in
the
MODE
dis-
play sequence.
(c)
MODE
display cleared.
3.
OUTPUT
display
(a) Initial
presentation:
C
OUTPUT
^
III
/ !
II II
ppm
Nine segments and
legends are presented.
(b)
Progressively,
all
seven-segment
digits
and
legends
are displayed
segment by
segment.
(c)
Final presentation:
Nine
commas
are displayed
on
OUTPUT
display then
all
18
commas
are displayed
on
OUTPUT
and
MODE
displays.
(d)
OUTPUT
and
MODE
displays cleared.
4.
MODE
Display
(a) Initial
presentation:
r
MODE
^
+7
n
lTl/
j
Polarity signs
and
overrange
digit displayed.
(b)
Progressively, seven-segment
digits are presented
digit
by
digit.
(c)
Final presentation.
MODE
r
mVkii
mil
1
mA
dB
1
L
rem
cal
ppmj
First,
then second blocks of legends
are displayed.
(d)
MODE
display
cleared.
5.
OUTPUT
display
digits are
presented
next,
in
the
same
order
as for the
MODE
display.
6.
LED
Check
sequence
commences:
(a)
Test
LED
stays on,
and
other
key
LEDs
are
lit
in
Left
to
Right sequence
starting at lOOp,
key and
ending
at
MODE
/////////
rem
ppm
OFF.
(b)
MODE
display.
Nine segments and
legends
are presented.
(b)
Progressively,
all
seven-segment
digits
and
legends
MODE
Symbol shown
indicates that the
keys
are ready
to
be
checked.
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