Remote supervisory control system

Details Remote supervisory control system Remote supervisory control system

1999-06-25

2002-10-01

Picard, Leo (Department: 2121)

Data processing: generic control systems or specific application

Generic control system, apparatus or process

Supervisory control

C700S019000, C700S083000, C700S286000, C315S295000, C315S318000

Reexamination Certificate

active

06459938

ABSTRACT:

BACKGROUND OF INVENTION
1. Field of Invention
The present invention relates to a remote supervisory control system.
2. Related Art
A remote supervisory control system having a configuration as shown in
FIG. 8
has conventionally been provided. The remote supervisory control system includes a transfer controller
30
, and a two-wire signal line Ls connected to the transfer controller
30
. The two-wire signal line Ls is connected to a plurality of operation terminals
31
and control terminals
32
through multidrop connection. Although, in the illustrated example, the single operation terminal
31
and a single control terminal
32
are connected to the signal line Ls, in practice many operation terminals
31
and many control terminals
32
can be connected to the signal line Ls. Further, in the illustrated example, a luminaire
33
including an illumination load is connected to the control terminal
32
, and the intensity of light output from the illumination load is instructed by the control terminal
32
. A dimmer for controlling the power supplied to the illumination load may be incorporated into the control terminal
32
or the luminaire
33
. In most cases where the illumination load is an incandescent lamp, the dimmer is incorporated into the control terminal
32
. In a case where the illumination load is a discharge lamp such as a fluorescent lamp, the dimmer is incorporated into the luminaire
33
.
Upon receipt of an instruction as to whether the intensity of light output from the illumination load is increased or decreased and an instruction for starting increase or decrease of the intensity of light output, the control terminal
32
changes the intensity of light output in the manner instructed. Upon receipt of an instruction for terminating the changing of light intensity, the control terminal
32
maintains the intensity of the light output at the point in time when the instruction is received. In this way, only two parameters: i.e., a point in time at which changing of intensity of light output is commenced and a point in time at which changing of intensity of light output is completed, are instructed. During the period between these two points in time, the control terminal
32
changes the intensity of light output automatically. A control terminal of this type is referred to as an autonomous dimmer terminal.
The operation terminal
31
is equipped with three push-type switches Sa to Sc. The switch Sa instructs illumination or extinction of the illumination load, and the switch Sb instructs an increase in the intensity of light output, as well as the start and stop of increase. The switch Sc instructs a decrease in the intensity of light output, as well as the start and stop of decrease. Decreasing and increasing operations are started by the user pressing the switches Sb and Sc, and these operations are stopped by the user releasing the same.
The operation terminals
31
and control terminals
32
are provided with individual addresses. Through use of the addresses, the transfer controller
30
perceives the individual operation terminals
31
and control terminals
32
.
The transfer controller
30
sends through the signal line Ls a transfer signal Vs having a format shown in FIG.
9
A. The transfer signal Vs is a bipolar time division multiplexed signal (of ±24V) comprising a synchronization signal SY representing the start of transmission of a signal; mode data MD representing the mode of the transfer signal Vs; address data AD for calling the operation terminals
31
and the control terminals
32
individually; control data CD for controlling the load L; checksum data CS for detecting transmission errors; and a signal return period WT which serves as a time slot for receiving a signal (monitoring data) returned from the operation terminal
31
or the control terminal
32
. Data are transferred through pulse-width modulation. (see FIG.
9
B). In each of the operation terminals
31
and the control terminals
32
, if the address data AD carried by the transfer signal Vs which is received by way of the signal line Ls match a preset address, the control data CD are captured from the transfer signal Vs. During the signal return period WT of the transfer signal Vs, monitoring data are returned as a current mode signal (i.e., a signal which is transmitted by short-circuiting the signal line Ls through use of a tool of appropriately low impedance).
When the transfer controller
30
transmits data to a desired one of the operation terminals
31
and control terminals
32
, the mode data MD of the transfer signal Vs are set to a control mode, and the address data AD of the transfer signal Vs are set to the address of the operation terminal
31
or the control terminal
32
. The thus-set transfer signal Vs is sent through the signal line Ls, and the operation terminal
31
or control terminal
32
whose address matches the address data AD of the transfer signal Vs receives the control data CD. During the signal return period WT, the terminal that has received the control data returns monitoring data. On the basis of the relationship between the control data CD transmitted from the transfer controller
30
and the monitoring received during the signal return period WT, the transfer controller
30
can ascertain whether or not the control data CD have been transmitted to the desired operation terminal
31
or control terminal
32
. In a case where the control terminal
32
receives the control data CD, the control terminal
32
outputs a load control signal for controlling the load L according to the control data CD. In a case where the operation terminal
31
receives the control data CD, the operation terminal
31
outputs a monitoring signal for checking and indicating the operation of the load L according to the control data CD.
The transfer controller
30
usually transmits, at given time intervals, a transfer signal Vs whose mode data MD are set to a dummy mode, and address data AD are cyclically changed (i.e., a full-time polling operation). When the operation terminal
31
attempts to send any information to the transfer controller
30
, an interrupt signal such as that shown in
FIG. 9C
is produced in synchronization with the synchronization signal SY of the transfer signal V
s
of dummy mode. At this time, the operation terminal
31
sets an interrupt flag to thereby prepare for subsequent exchange of information with the transfer controller
30
. Upon receipt of the interrupt signal, the transfer controller
30
sets the mode data MD of the transfer signal Vs to an interrupt polling mode and gradually increases half of the higher-order bits of the address data AD (i.e., four higher-order bits of the 8-bit address data AD). The transfer signal Vs is then transmitted. When a match exists between the four higher-order bits of the address data AD of the transfer signal Vs whose mode data MD are set to the interrupt polling mode and the four higher-order bits of the address assigned to the operation terminal
31
, the operation terminal
31
that has sent the interrupt signal returns the lower-order bits of the address data AD to the transfer controller
30
during the signal return period WT. As mentioned above, since the transfer controller
30
searches for the operation terminal
31
that has generated the interrupt signal, in units of 16 terminals, the operation terminal
31
can be found in a comparatively short period of time.
Upon acquisition of the address of the operation terminal
31
that has generated the interrupt signal, the transfer controller
30
sets the mode data MD of the transfer signal Vs to a monitoring mode, and the transfer signal whose address data AD matches the thus-acquired address is sent to the signal line Ls. In response to the transfer signal Vs, the operation terminal
31
returns the information to be transmitted during the signal return period WT. Finally, the transfer controller
30
sends a signal for instructing interruption reset to the operation terminal
31
that has generated the interrupt signal, thus clearin

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