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1711 Data Converter Features
The 1711 Data Converter contains an Analog-to-Digi-
tal Converter
(ADC) ,
a Real-Time Clock
(RTC) ,
a Ter-
minal Address Selector
(TAS) ,
and an Operator's Panel.
Analog-to-Digital Converter (ADC)
The
ADC
enables the 1710 to accept analog voltages or
currents from customer instruments and transducers.
Fifty milliseconds are required for each analog signal
conversion (a maximum of 20 conversions per second) .
Analog Input functions, available in increments of
two, include SMS cards for matching (transforming
incoming current signals to an acceptable voltage level)
and filtering (reducing the effect of spurious signals) .
Analog Input functions cannot be terminated on ter-
minal blocks containing Contact Operate and Analog
Output functions.
Analog
Inputs
SMS matching
and
filter cards
Multiplexing
relay cards
Standard SMS cards are available for terminating the
following signals which may be of either polarity:
o
to 50 millivolts
o
to 5 milliamperes
o
to 20 milliamperes
o
to 50 milliamperes
Signal polarity is determined as a part of the function
of signal conversion.
SMS cards for signals outside of the ranges listed are
available by special order.
Analog Input
The program selects each analog signal individually
via
TAS
(Terminal Address Selector) and the multi-
plexing relays. As shown in Figure 6, an analog signal
passes through a multiplexing relay contact and into
the
ADC
(Analog-to-Digital Converter) . The converted
signal, which will be in the digital range of 0000 to
Analog-
to- Digital
r----~
_-+_~
____
-+I Converter
1620
Core
Storage
J.<'igure 6. Analog Input Data Flow
12
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