Theory
of Operation—DM 5010
ATTENUATOR
<$>
The input signal to be measured passes through a resis
tive
attenuator network that
prescales the analog signal to
fall
within the input circuitry’s dynamic range. Attenuation
factors
of
1 and 100 are controlled by closing contacts of
relays
K1527,
K1425, and K1525 as shown in Fig. 4-1
and
Tables 10-2 and
10-5 in the
pull out pages.
OVERVOLTAGE
PROTECTION AND
FUNC
TION SWITCHING <J>
All
measurement modes of the DM 5010 require that
some
type of
conditioning
be performed
on the input signal
before
an
A/D conversion is performed. In each case, the
input
conditions
are converted to a representative de volt
age level
by
the
appropriate conditioning circuitry and are
then applied to
the DCV Signal Conditioner
where some
range-dependent
gain factor is applied to the signal. This
resultant
prescaled
signal is the basis for all A/D conver
sions
and, along with the various mode, attenuation, and
gain
factors
set by the microprocessor, represents the input
conditions.
This stage selects
the
appropriate conditioning circuit
output
and
routes it to the DCV Signal Conditioner input. It
also
provides overvoltage protection should these signals
exceed
the
specified input
range.
A
simplified schematic of the Overvoltage Protection and
Function
Switching stage appears
in
Fig. 4-2. Each of the
FET
switches connects either an
individual function or the
high quality ground reference to the DCV Signal
Conditioner
when
closed.
Refer to Tables 10-2 and 10-5 in the pull out
pages
for mode-dependent function and range switch
settings.
Transistors Q1327
and Q1323
connected as diodes pre
vent
the input voltage applied to FET switch Q1319 from
exceeding
« + 23 volts and —23 volts, respectively. Similar
ly,
transistors Q1321 and Q1322 prevent the
output voltage
of
the
Ohms Converter
from exceeding the same voltages.
Fig. 4-1. Attenuator.
ADD
JAN
1982
4-5
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 337: ...63 REV JUN 1986...
Page 338: ...FIG 1 EXPLODED DM 5010...
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