Electrical supervisory control and data acquisition system

• US 4,558,316 A
• Filed: 03/22/1984
• Issued: 12/10/1985
• Est. Priority Date: 04/10/1980
• Status: Expired due to Fees

• Current Assignee: Fui K. Yong
• Original Assignee: Fui K. Yong
• Inventors: Yong, Fui K.
• Primary Examiner(s): Yusko, Donald J.
• Application Number:
  US06/593,183
• Time in Patent Office: 628 Days
• Field of Search: 340/825.06, 340/825.07, 340/825.63, 340/825.64, 340/825.57, 340/521, 340/52 F, 340/825.52, 340/825.54, 340/870.24, 340/870.19 , 340/825.37, 307/10 R
• US Class Current: 340/3.55
• CPC Class Codes: G08B 3/1008 Personal calling arrangements or devices, i.e. paging systems selective calling systems and call receivers H04W84/00, H04W68/00
• CPC Class Codes: H04M 11/027 Annunciator systems for hospitals
• CPC Class Codes: H04Q 9/16 by predetermined number of pulses

Abstract

An electrical control system which comprises: a master station (2) and a plurality of receiver stations (4) connected thereto by a bus, (6), the master station including generating means (20, 22) for generating control signals (18) which are applied to said bus and to which said receiver stations are responsive, the control signals comprising a repetitive series of signal frames, each frame including a reset pulse (18) and a plurality of other pulses, the master station including control means (14) which causes selectable alteration of a characteristic of said other pulses, and wherein each of said receiver stations is addressed following receipt of a predetermined number of said other pulses, said receivers being responsive to said selectable characteristic of the other pulses whereby information is transmitted to addressed receiver stations in accordance with operation of said control means, whereby data and address information are constituted in the same pulses. The system may further include circuitry which permits the receiver being addressed to transmit information to the master station. The system would have wide applications, for instance, in nurse paging systems in hospitals.

Claims

1. An electrical control system comprising:

a master station and a plurality of receiver stations connected thereto by a bus;

said mastser station including generating means for generating control signals which are applied to said bus and to which said receiver stations are responsive;

said control signals comprising a repetitive series of signal frames, each signal frame including a reset pulse and a plurality of address pulses;

said master station also including control means which can cause selectable alteration of the duration of any address pulse and also the period between successive address pulses;

said receiver stations being respectively addressed in a frame following receipt of a predetermined number of said address pulses after the reset pulse;

the addressed receiver stations being responsive to the duration of the address pulse by which it is addressed whereby output information can be transmitted from the master station to the receiver station thus addressed;

the receiver stations including return signal generating means for generating return signals which vary the impedance of the bus;

said master station also including measuring means coupled to the bus for measuring the variation of the impedance of the bus; and

the reset pulse of each signal frame being distinguishable from the other pulses thereof by virtue of its relatively long duration, the output information being determined by the duration of the period between successive address pulses and the return signals are generated by varying the bus impedance by the addressed receiver station during the same period that the receiver is addressed, whereby the master station can transmit output information to an addressed receiver station by varying the duration of the period between successive pulses and simultaneously measure the variation of the bus impedance which defines the return signal generated by the addressed receiver.

2. A system as claimed in claim 1, wherein:

said bus comprises of a minimum of two wires;

said pulses comprise of voltage pulses on a non-zero datum;

said voltage pulses can provide power for at least some of the receiver stations;

said output information is determined by the period the bus is at the said non-zero datum voltage;

said return signals comprise of varying bus impedance during the period the bus is at the said non-zero datum voltage.

3. A system as claimed in claim 1, wherein:

said bus comprises a minimum of two wires;

said pulses comprises of voltage pulses on a non-zero datum;

said voltage pulses can provide power for at least some of the receiver stations;

said output information is determined by the number of zero volt pulses during the period between said other voltage pulses;

said return signals comprise of varying bus impedance during the period the bus is at the said non-zero volt datum.

4. An electrical control system comprising:

a master station and a plurality of receiver stations connected thereto by a two-wire bus;

said master station including generating means for generating control signals which are applied to said two-wire bus and to which said receiver stations are responsive;

said control signals comprising a repetitive series of signal frames, each signal frame including a reset pulse and a plurality of address pulses;

said master station also including control means which can cause selectable alteration of the duration of any address pulse and also the period between successive address pulses;

said receiver stations being respectively addressed in a frame following receipt of a predetermined number of said address pulses after the reset pulse;

the addressed receiver stations being responsive to the duration of the address pulse by which it is addressed whereby output information can be transmitted from the master station to the receiver station thus addressed;

the receiver stations including return signal generating means for generating return signals which vary the impedance of the two-wire bus;

said master station also including measuring means coupled to the two-wire bus for measuring the variation of the impedance of the bus; and

the reset pulse of each signal frame being distinguishable from the other pulses thereof by virtue of its relatively long duration, the output information being determined by the duration of the period between successive address pulses and the return signals are generated by varying the bus impedance by the addressed receiver station during the same period that the receiver is addressed, whereby the master station can transmit output information to an addressed recevier station by varying the duration of the period between successive pulses and simultaneously measure the variation of the bus impedance which defines the return signal generated by the addressed receiver.

5. A system as claimed in claim 4, wherein:

said pulses comprise of voltage pulses on a non-zero datum;

said voltage pulses can provide power for at least some of the receiver stations;

said output information is determined by the period the bus is at the said non-zero datum voltage;

said return signals comprise of varying bus impedance during the period the bus is at the said non-zero datum voltage.

6. A system as claimed in claim 4, wherein:

said pulses comprises of voltage pulses on a non-zero datum;

said voltage pulses can provide power for at least some of the receiver stations;

said output information is determined by the number of zero volt pulses during the period between said other voltage pulses;

said return signals comprise of varying bus impedance during the period the bus is at the said non-zero volt datum.