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Data setting system for terminal units in remote supervisory and controlling system employing data transmission

  • US 5,444,439 A
  • Filed: 07/08/1994
  • Issued: 08/22/1995
  • Est. Priority Date: 09/27/1988
  • Status: Expired due to Term
First Claim
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1. A data setting system for terminal units in a remote supervisory and controlling system, comprising:

  • a central control unit;

    a plurality of said terminal units connected to said central control unit through a two-wire signal line, each of said terminal units having a set address, a plurality of operational modes, and a plurality of functions operating according to function data values;

    means for carrying out a time-divisional multiplex data transmission between said central control unit and said terminal units, or between the respective terminal units with transmissions transmitted from the central control unit to the respective terminal units or from one of the terminal units to the central control unit or other terminal units, said central control unit supplying through said two-wire signal line, a source of power to the respective terminal units, and said transmissions including at least an address data signal from one of the control and terminal units for calling another of the units, a control data signal from said one unit to said another unit called and a supervisory data signal from said another unit called to said one unit; and

    operating means provided separately from said terminal units for preparing an optical wireless signal for transmission to said terminal units, said optical wireless signal comprising said function data values, data representing one of said operational modes, and setting mode data, said setting mode data representing one of a data setting mode and a confirmation only mode;

    each of said terminal units comprising;

    a memory for storing said function data values;

    light receiving means for receiving said optical wireless signal from said operating means;

    means for sending to said operating means said function data values stored in said memory in response to said received optical wireless signal via a return optical wireless signal; and

    signal processing means which processes said received optical wireless signal for switching an operational mode of the terminal unit on the basis of said function data values stored in said memory and said data representing said one of said operational modes from said received optical wireless signal, said signal processing means being operable in said data setting mode to write said function data values in said memory responsive to said setting mode data in said optical wireless signal indicating said data setting mode and operable in said confirmation only mode to read out function data stored in said memory and send it to said operating means via said return optical wireless signal responsive to said setting mode data indicating said confirmation only mode;

    wherein said central control unit stores a reference code specific to said data setting system, and said optical wireless signal further comprises collating code data set in accordance with specific uses of each of the terminal units and a code specific to the data setting system which corresponds to the reference specific code stored in said central control unit for judgment at the central control unit of coincidence of said optical wireless signal received with said specific code stored in said central control unit, andwherein said system comprises means for preventing operation in said data setting mode when said specific code in said optical wireless signal does not coincide with said reference specific code stored in said central control unit, and means for determining whether said collating code in said received optical wireless, signal coincides with said collating code data in said memory of said terminal units and for preventing operation of said data setting mode if said collating code does not coincide with said collating code data.

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