Single transmission line data acquisition system
First Claim
1. A single transmission line multiple channel data acquisition system, comprising:
- a master station means for generating address pulses at a selected frequency for separately sequentially addressing a plurality of cycle responsive data channels during a scanning sequence and receiving quantitative data values corresponding to the addressed one of said channels during an address pulse cycle period;
a plurality of remote station/sensor means corresponding to said plurality of data channels, each remote station/sensor means including a power storage means responsive to a supply voltage applied to an input of said remote station/sensor means for storing electrical energy to power said remote station/sensor means, a presettable address counter means for counting said address pulses received at said input thereof to determine when the channel is addressed in accordance with a preselected count of said address pulses and transmitting circuit means for measuring and transmitting the addressed channel quantitative data value in the form of a pulse position coded signal at an output of said remote station/sensor means;
a transmission line connected between said master station and the input and output of each of said plurality of remote station/sensor means for transmitting said address pulses to each of said plurality of remote station/sensor means and said pulse position coded signals from each of said plurality of remote station/sensor means to said master station means; and
means for automatically maintaining a constant supply voltage on said transmission line for charging each power storage means of each of said remote station/sensor means independent of the number of said plurality of remote station/sensor means.
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Accused Products
Abstract
A single transmission line interrogated multiple channel data acquisition system is provided in which a plurality of remote station/sensors monitor specific process variables and transmit measurement values over the single transmission line to a master station when addressed by the master station. Power for all remote stations (up to 980) is provided by driving the line with constant voltage supplied from the master station and automatically maintained independent of the number of remote stations directly connected to the line. The transmission line can be an RG-62 coaxial cable with lengths up to about 10,000 feet with branches up to 500 feet. The remote stations can be attached randomly along the line. The remote stations can be scanned at rates up to 980 channels/second.
20 Citations
4 Claims
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1. A single transmission line multiple channel data acquisition system, comprising:
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a master station means for generating address pulses at a selected frequency for separately sequentially addressing a plurality of cycle responsive data channels during a scanning sequence and receiving quantitative data values corresponding to the addressed one of said channels during an address pulse cycle period; a plurality of remote station/sensor means corresponding to said plurality of data channels, each remote station/sensor means including a power storage means responsive to a supply voltage applied to an input of said remote station/sensor means for storing electrical energy to power said remote station/sensor means, a presettable address counter means for counting said address pulses received at said input thereof to determine when the channel is addressed in accordance with a preselected count of said address pulses and transmitting circuit means for measuring and transmitting the addressed channel quantitative data value in the form of a pulse position coded signal at an output of said remote station/sensor means; a transmission line connected between said master station and the input and output of each of said plurality of remote station/sensor means for transmitting said address pulses to each of said plurality of remote station/sensor means and said pulse position coded signals from each of said plurality of remote station/sensor means to said master station means; and means for automatically maintaining a constant supply voltage on said transmission line for charging each power storage means of each of said remote station/sensor means independent of the number of said plurality of remote station/sensor means. - View Dependent Claims (2, 3, 4)
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Specification