Theory of
Operation
—DM 5010
FRONT-PANEL
SWITCHES <12>
The Front-Panel Switches provide a way for the user to
control
the
operation of
the DM 5010.
Forty
push button switches are arranged in a 5 X 8 ma
trix and are
continuously
scanned under control of the spe
cial Front-Panel
Control IC and the 1-of-8 decoder in the
Front-Panel Drive
stage. The 1-of-8 decoder sets each of
the
eight columns of the matrix low, one at
a time, and
then
each of the five
rows are sequentially checked by the Front-
Panel
Control IC to see if a switch closure is present. After
all five
rows have been
scanned, the next column is set low
by
the decoder and the
sequence is repeated. Switch clo
sure
data is stored by the Front-Panel Control IC and is
further
explained
in that description.
FRONT-PANEL
DISPLAY <
12>
The
Front-Panel Display provides a visual indication of
instrument status and
measurement results to the user.
It
is
comprised
of
multi-segment
displays and
individual light
emitting diodes arranged
in a matrix configuration. The dis
play is generated
in much the same way as when the Front-
Panel Switches are
scanned.
The Front-Panel Control IC, along with
the 1-of-8 decod
er
in the Front-Panel Drive circuitry, enables one of the mult
segment
displays or one of the
columns of status
LEDs by
pulling
the
associated anodes
high
through the buffering cir
cuitry
on diagram
11. As each group of anodes is enabled,
an 8-bit display word associated with the particular column
enabled
is output from the Front-Panel
Control
IC on lines
CD0-CD7
(Cathode Data 0-Cathode
Data 7). This is the
data
stored earlier by the microprocessor representing the
LEDs
that should be turned on
in any given display digit or
status
column.
The data is buffered by the Front-Panel Drive
circuitry
and
applied to
the
eight cathode rows. Any cathode
that is low when its
respective anode is held high will
illuminate.
4-30
ADD
JAN
1982
Summary of Contents for DM 5010
Page 14: ...DM 5010 2994 00 DM 5010 Programmable Digital Multimeter xii ADD JUL 1986...
Page 27: ...Operating Instructions DM 5010 2994 03 Fig 2 3 DM 5010 front panel controls and connectors 2 3...
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Page 251: ...Section 8 DM 5010 OPTIONS No options are available 8 1...
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Page 272: ...DM 5010 2994 37 Fig 10 2 Location of DM 5010 adjustments and test points...
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Page 276: ...DM 5010 2994 112 DM 5010 BLOCK DIAGRAM...
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Page 337: ...63 REV JUN 1986...
Page 338: ...FIG 1 EXPLODED DM 5010...
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