Communication system and communication apparatus
AssigneeMitsubishi Electric Corporation
InventorsHiroaki KOTAKE, Yoshiaki KOIZUMI, Takuya MUKAI, Masahiro ISHIHARA
Life of this patent
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Abstract
A communication system comprises a communication device and communication devices. The communication device comprises a direct current power supply and a transmitter configured to transmit data by control of a current flowing through a current loop. The communication devices comprise a receiver configured to receive data by detection of the current flowing through the current loop. The communication device comprises an adjuster configured to adjust the impedance between a signal line and a common line according to the number of communication devices.
Claims14
A communication system comprising:
- a first communication device;
- and
- at least one second communication device connected in parallel to the first communication device by a signal line, a common line and a power line,
- wherein
- the first communication device comprises
- a direct current power supply configured to generate a direct current for serial communication from alternating current power supplied from an alternating current power supply through the power line and the common line, and pass the generated direct current through a current loop comprising the signal line and the common line that are connected in series, and
- a transmitter configured to transmit data by control of a current flowing through the current loop,
- the at least one second communication device comprises a receiver configured to receive data by detection of the current flowing through the current loop,
- at least one device of the first communication device or the at least one second communication device further comprises an adjuster configured to adjust impedance between the signal line and the common line based on a number of the at least one second communication device, and
- the adjuster comprises a switcher configured to switch, based on the number of the at least one second communication device, a state between the signal line and the common line between (i) a state of connection via a first load resistor and (ii) a state of disconnection via the first load resistor.
A communication system comprising:
- a first communication device;
- and
- at least one second communication device connected in parallel to the first communication device by a signal line, a common line and a power line,
- wherein
- the first communication device comprises
- a direct current power supply configured to generate a direct current for serial communication from alternating current power supplied from an alternating current power supply through the power line and the common line, and pass the generated direct current through a current loop comprising the signal line and the common line that are connected in series, and
- a transmitter configured to transmit data by control of a current flowing through the current loop,
- the at least one second communication device comprises a receiver configured to receive data by detection of the current flowing through the current loop,
- at least one device of the first communication device or the at least one second communication device further comprises an adjuster configured to adjust impedance between the signal line and the common line based on a number of the at least one second communication device,
- the adjuster is configured to adjust the impedance between the signal line and the common line so that the impedance between the signal line and the common line is within a certain range regardless of the number of the at least one second communication device,
- the adjuster comprises a plurality of series circuits each comprising a second load resistor and a second photocoupler that are connected in series between the signal line and the common line, and
- the adjuster is configured to allow the second photocoupler of a series circuit of the plurality of series circuits to be conductive, the second photocoupler being selected based on the number of the at least one second communication device.
A communication device for serial communication with at least one other communication device, the communication device comprising:
- a direct current power supply configured to generate a direct current for serial communication from alternating current power supplied from an alternating current power supply through a power line and a common line, and pass the generated direct current through a current loop comprising a signal line and the common line that are connected in series;
- a transmitter configured to transmit data by control of a current flowing through the current loop;
- and
- an adjuster configured to adjust impedance between the signal line and the common line based on a number of the at least one other communication device,
- wherein the at least one other communication device is connected in parallel to the communication device by the signal line, the common line and the power line, and
- wherein the adjuster comprises a switcher configured to switch, based on the number of the at least one other communication device, a state between the signal line and the common line between (i) a state of connection via a first load resistor and (ii) a state of disconnection via the first load resistor.
A communication device that is any of at least one communication device connected in parallel to another communication device by a signal line, a common line and a power line, the other communication device including a direct current power supply configured to generate direct current power for serial communication from alternating current power supplied from an alternating current power supply, the communication device comprising:
- a receiver configured to receive data by detection of a current flowing through a current loop comprising the signal line and the common line that are connected in series;
- and
- an adjuster configured to adjust impedance between the signal line and the common line based on a number of the at least one communication device,
- wherein the adjuster comprises a switcher configured to switch, based on the number of the at least one communication device, a state between the signal line and the common line between (i) a state of connection via a first load resistor and (ii) a state of disconnection via the first load resistor.
A communication device for serial communication with at least one other communication device, the communication device comprising:
- a direct current power supply configured to generate a direct current for serial communication from alternating current power supplied from an alternating current power supply through a power line and a common line, and pass the generated direct current through a current loop comprising a signal line and the common line that are connected in series;
- a transmitter configured to transmit data by control of a current flowing through the current loop;
- and
- an adjuster configured to adjust impedance between the signal line and the common line based on a number of the at least one other communication device,
- wherein
- the at least one other communication device is connected in parallel to the communication device by the signal line, the common line and the power line,
- the adjuster is configured to adjust the impedance between the signal line and the common line so that the impedance between the signal line and the common line is within a certain range regardless of the number of the at least one other communication device,
- the adjuster comprises a plurality of series circuits each comprising a second load resistor and a second photocoupler that are connected in series between the signal line and the common line, and
- the adjuster is configured to allow the second photocoupler of a series circuit of the plurality of series circuits to be conductive, the second photocoupler being selected based on the number of the at least one other communication device.
A communication device that is any of at least one communication device connected in parallel to another communication device by a signal line, a common line and a power line, the other communication device including a direct current power supply configured to generate direct current power for serial communication from alternating current power supplied from an alternating current power supply, the communication device comprising:
- a receiver configured to receive data by detection of a current flowing through a current loop comprising the signal line and the common line that are connected in series;
- and
- an adjuster configured to adjust impedance between the signal line and the common line based on a number of the at least one communication device,
- wherein
- the adjuster is configured to adjust the impedance between the signal line and the common line so that the impedance between the signal line and the common line is within a certain range regardless of the number of the at least one communication device,
- the adjuster comprises a plurality of series circuits each comprising a second load resistor and a second photocoupler that are connected in series between the signal line and the common line, and
- the adjuster is configured to allow the second photocoupler of a series circuit of the plurality of series circuits to be conductive, the second photocoupler being selected based on the number of the at least one communication device.
Dependencies are inferred from the claim text.