Data acquisition system
First Claim
1. A data acquisition system comprising:
- a plurality of distributed sensors, each one of which is adapted to provide a voltage output indicative of a value or condition sensed thereby;
a plurality of nodal units to which the outputs of respective sets of said sensors are connected; and
a central unit adapted to receive data from said sets of sensors in response to its repetitive interrogation, in turn, of the respective said nodal units to which the sets of sensors are connected;
each said nodal unit being adapted to derive, in respect of each said sensor in the set connected thereto, a pulse signal the width of which represents the voltage level of the respective sensor output and to transmit the corresponding set of pulse signals, in turn, to the central unit when interrogated thereby.
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Accused Products
Abstract
A data acquisition system, e.g. for an intrusion alarm system, has a plurality of distributed sensors connected in sets to nodal units or concentrators. The concentrators are interrogated by clock pulses broadcast from a central control unit and when each concentrator'"'"'s address is reached it transmits back to the central unit a set of pulse signals the widths of which represent the voltage levels of the respective sensors connected to it. Analogue sensor outputs may thus be transmitted. The sensor outputs are also preferably integrated at the concentrators, prior to pulse-conversion, over a period corresponding to a complete cycle of the local mains supply, thus to eliminate any mains interference.
12 Citations
11 Claims
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1. A data acquisition system comprising:
- a plurality of distributed sensors, each one of which is adapted to provide a voltage output indicative of a value or condition sensed thereby;
a plurality of nodal units to which the outputs of respective sets of said sensors are connected; and
a central unit adapted to receive data from said sets of sensors in response to its repetitive interrogation, in turn, of the respective said nodal units to which the sets of sensors are connected;
each said nodal unit being adapted to derive, in respect of each said sensor in the set connected thereto, a pulse signal the width of which represents the voltage level of the respective sensor output and to transmit the corresponding set of pulse signals, in turn, to the central unit when interrogated thereby. - View Dependent Claims (2, 3, 4, 5, 6, 8, 9, 10, 11)
- a plurality of distributed sensors, each one of which is adapted to provide a voltage output indicative of a value or condition sensed thereby;
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7. A system according to caim 6 wherein each nodal unit includes means for synchronising with said clock pulses its transmission of said pulse signals to the central unit.
Specification