Control/supervisory signal transmission system

• US 5,223,826 A
• Filed: 06/01/1990
• Issued: 06/29/1993
• Est. Priority Date: 08/26/1988
• Status: Expired due to Term

• Current Assignee: Kuroda Precision Industries Ltd., Nakamura KIKI Engineering Company Limited
• Original Assignee: Nakamura KIKI Engineering Company Limited
• Inventors: Amou, Teruhiko, Saito, Yoshitane
• Primary Examiner(s): Yusko, Donald J.
• Assistant Examiner(s): Weissman, Peter S.
• Application Number:
  US07/532,433
• Time in Patent Office: 1,124 Days
• Field of Search: 340/825.06, 340/825.07, 340/825.36, 340/825.37, 340/825.57, 340/825.65, 340/288, 340/310 R
• US Class Current: 340/3.2
• CPC Class Codes: G08C 15/12 the signals being represented by pulse characteristics in transmission link

Abstract

A bidirectional control/supervisory system for transmitting control signals from a controller to devices and transmitting supervisory signals from sensors monitoring the devices to the controller through a common transmission line. A transmission/reception control circuit generates a timing signal and a supply voltage of constant level, and converts the voltage into clock pulses having voltage levels differing from the supply voltage. The clock pulses are outputted to the common transmission line under the timing of the timing signals. A first unit group is connected to the controller and the transmission/reception control circuit through the transmission line and includes first transmitter units connected thereto for modulating the level of the clock pulses with control data supplied from the controller and first receiver units connected to the controller and to the transmission/reception control circuit through the transmission line for extracting supervisory signals of the sensors to supply them to the controller. A second group is connected to the transmission/reception control circuit and includes second receiver units connected to the sensors and the common transmission line for demodulating the level of the clock pulses to extract the control data to be supplied to the devices and second transmitter units connected to the sensors and the common line for modulating the levels of the clock pulses with supervisory data signals supplied from the sensors for transmission thereof to the first receiver units.

Claims

1. A control/supervisory signal transmission system for transmitting control signals from a controller to controlled devices and transmitting supervisory signals from sensors monitoring said controlled devices to said controller through a common data signal line, comprising:

transmission/reception timing control means including timing generator means for generating a timing signal, power supply means for generating a power supply voltage of a predetermined constant level (V_x), voltage conversion means connected to said power supply means and said timing generator means for converting to said power supply voltage into a series of pulse-like voltage signals in synchronism with said timing signal, wherein said pulse-like voltage signals have two different voltage levels (v_x /2 and 0 volts) differing from said power supply level (v_x) said two different voltage levels are outputted onto said data signal line;

a first unit group connected to said controller and to said transmission/reception timing control means by way of at least said data signal line and including at least one first transmitter unit connected to said data signal line for receiving said timing signal to thereby modulate the level of said series of pulse-like voltage signals on said data signal line with control data supplied in parallel from said controller in synchronism with said timing signal, and at least one first receiver unit connected to said controller and to said transmission/reception timing control means by way of said signal data line for extracting the serial supervisory signals originating in said sensors from said data signal line in synchronism with said timing signal to thereby supply said supervisory signals to said controller in parallel; and

a second unit group connected to said transmission/reception timing control means and including at least one second receiver unit connected to said controlled devices and to said data signal line for demodulating the level of said serial pulse-like voltage signals supplied from said first transmitter unit over said data signal line to thereby extract said control data to be supplied to said controlled devices in synchronism with said timing signal and at least one second transmitter unit connected to said sensors and said data signal line for receiving said timing signal to thereby modulate the levels of said serial pulse-like voltage signals on said data signal line with supervisory data signals supplied parallel from said sensors for transmission thereof to said first receiver unit in synchronism with said timing signal.

2. A control/supervisory signal transmission system according to claim 1, wherein each of said transmitter units and said receiver units of said first and second unit groups includes first power generating means for generating from said pulse-like voltage signal a power supply voltage of a constant level for electrically energizing component circuits constituting each of said units.

3. A control/supervisory signal transmission system according to claim 1, wherein each of said transmitter units and each of said receiver units of said second unit groups includes second power generating means for generating from said pulse-like voltage signal a power supply voltage for electrically driving said controlled devices and said sensors, respectively.

4. A control/supervisory signal transmission system according to claim 2, wherein each of said transmitter units and each of said receiver units of said second unit groups includes second power generating means for generating from said pulse-like voltage signal a power supply voltage for electrically driving said controlled devices and said sensors, respectively.

5. A control/supervisory signal transmission system according to claim 1, wherein said controlled devices and said sensors are electrically driven from said power supply means of said transmission/reception timing control means by way of a power transmission line.

6. A control/supervisory signal transmission system according to claim 1, said control data signal and said supervisory signal being binary signals, respectively, wherein the level of said pulse-like voltage signals is modulated with said binary signals to two discriminable data levels (V_x /2 volts and 0 volt) corresponding to "OFF" and "ON" levels, respectively of said binary signal relative to a non-data level (V_x).

7. A control/supervisory signal transmission system according to claim 1, wherein said first transmitter unit of said first unit group and said second receiver unit of said second unit group are provided a number of m in pairs, respectively, being associated in one-to-one correspondence with each other and connected to said data signal line in a predetermined order in the respective unit groups, while said first receiver unit of said first unit group and said second transmitter unit of said second unit group are provided in a number of n pairs, respectively, being associated in one-to-one correspondence with each other and connected to said data signal line in a predetermined order in the respective unit groups, so that the associated transmitter and receiver units are successively operated in said predetermined order to thereby transfer the control data signals and the supervisory signals for and from the respective controlled devices and sensors under the control of said timing signal.

8. A control/supervisory signal transmission system according to claim 7, further including a terminating unit installed in succession to a final stage of the units connected in said predetermined order within one of said first and second unit groups, wherein said terminating unit includes means for generating a signal of a predetermined wave form at every end of transmission of one frame to all the units belonging to the group in which said terminating unit is installed, and wherein said transmission/reception timing control means including check circuit means for checking the line state of said data signal line in response to said signal of predetermined wave form.

9. A control/supervisory signal transmission system according to claim 7, said timing generator means of said transmission/reception timing control means including first start signal generating means for generating a first start signal, while each of said transmitter units and said receiver units includes second start signal generating means for generating a second start signal, wherein first pair of the associated transmitter unit and receiver unit in said sequence in said first and second unit groups are triggered into transfer operation in response to said first start signal, and upon completion of operation of said first pair of the transmitter and receiver units, said second start signal generating means generates said second start signal for triggering transfer operation of a succeeding pair of the transmitter unit and the receiver unit in said first and second groups, said triggering by said second start signal being repeated until the last pair of the transmitter and receiver units in said sequence is triggered into transfer operation.

10. A control/supervisory signal transmission system according to claim 9, said transmitter units and said receiver units are connected to one another through a start signal line for carrying said second start signals, wherein said first start signal is conveyed to said first pair of the transmitter unit and said receiver unit through said data signal line in a discriminable waveform.

11. A control/supervisory signal transmission system according to claim 9, wherein said transmission/reception timing control means, said transmitter units and said receiver units are connected to one another through start signal lines for carrying said start signals.

12. A control/supervisory signal transmission system according to claim 1, said transmitter and receiver units in said first and second unit groups being connected to said common data signal line at arbitrarily given locations,

wherein said transmission/reception timing control means includes start signal generating means for generating a start signal to be supplied to said transmitter and receiver units, respectively, over said data signal line in a discriminable waveform,

each of said transmitter and receiver units including means for extracting a clock signal from said modulated pulse-like voltage signal, counter means for counting said clock signal in response to said start signal, and address setting means for holding an address allocated to the associated unit,

wherein when the count value of said counter means has attained a value representing said address, the associated unit starts transmitting or receiving operation.

13. A control/supervisory signal transmission system according to claim 12, wherein a plurality of said receiver units belonging to said second unit group are allocated with a same address so that said plurality of receiver units of the second unit group are operated simultaneously with one of said transmitter units belonging to said first unit group.

14. A control/supervisory signal transmission system according to claim 12, wherein a plurality of said receiver units belonging to said first unit group are allocated with a same address so that said plurality of receiver units of the first unit group are operated simultaneously with one of said transmitter units belonging to said second unit group.

15. A control/supervisory signal transmission system according to claim 1, said transmitter and receiver units in said first unit group being connected to said common data signal line in a predetermined sequential order, while said transmitter units and said receiver units in said second group are connected to said data signal line in an arbitrary sequential order,

wherein said transmission/reception timing control means includes start signal generating means for generating a start signal to be supplied to said transmitter and receiver units of said second group over said data signal line in a discriminable waveform and to said transmitter and receiver unit of said first group over a start signal line for starting operation of said transmitter and receiver units of said first group successively in said sequential order,

each of said transmitter and receiver units of said second group including means for extracting a clock signal from said modulated pulse-like voltage signal, counter means for counting said clock signal in response to said start signal, and address setting means for holding an address allocated to the associated unit, wherein when the count value of said counter means has attained a value representing said address, the associated unit starts transmitting or receiving operation.

16. A control/supervisory signal transmission system according to claim 1, said transmitter and receiver units in said second unit group being connected to said common data signal line in a predetermined sequential order, while said transmitter units and said receiver units in said first group are connected to said data signal line in an arbitrary sequential order,

wherein said transmission/reception timing control means includes start signal generating means for generating a start signal to be supplied to said transmitter and receiver units of said first group over said data signal line in a discriminable waveform and to said transmitter and receiver unit of said second group over a start signal line for starting operation of said transmitter and receiver units of said second group successively in said sequential order,

each of said transmitter and receiver units of said first group including means for extracting a clock signal from said modulated pulse-like voltage signal, counter means for counting said clock signal in response to said start signal, and address setting means for holding an address allocated to the associated unit, wherein when the count value of said counter means has attained a value representing said address, the associated unit of said first starts transmitting or receiving operation.