Hafe-duplex two-wire DC power-line communication system

• US 5,986,539 A
• Filed: 06/08/1998
• Issued: 11/16/1999
• Est. Priority Date: 06/08/1998
• Status: Expired due to Fees

• Current Assignee: Ultracision, Inc. (Giga-tronics, Inc.)
• Original Assignee: Ultracision, Inc. (Giga-tronics, Inc.)
• Inventors: Johansson, Fritz H., Hampton, Gordon P.
• Primary Examiner(s): Lefkowitz, Edward
• Assistant Examiner(s): GOINS, DAVETTA WOODS
• Application Number:
  US09/093,964
• Time in Patent Office: 526 Days
• Field of Search: 340/310.01, 340/825.07, 340/539, 340/657, 340/538, 370/463, 370/357, 370/215, 370/276, 370/477, 307/106
• US Class Current: 370/535
• CPC Class Codes: H04B 2203/5425 improving S/N by matching impedance, noise reduction, gain control
• CPC Class Codes: H04B 2203/5458 Monitor sensor; Alarm systems
• CPC Class Codes: H04B 2203/547 via DC power distribution
• CPC Class Codes: H04B 2203/5483 using coupling circuits
• CPC Class Codes: H04B 2203/5495 having measurements and testing channel
• CPC Class Codes: H04B 3/548 the power on the line being DC arrangements for feeding power H04L12/10; extracting feeding power from signals H04L25/02
• CPC Class Codes: H04L 12/40045 Details regarding the feeding of energy to the node from the bus
• CPC Class Codes: H04L 12/403 with centralised control, e.g. polling

Abstract

A powerline communication system comprises a master and slave configuration in which the master provides both operating power and control commands to the slave over a single pair of wires. The slave, in turn, is able to communicate its status to the master with a return communications channel on the same pair of wires. Each sender impresses its signals on the power lines with an isolation transformer coupled to the gate of a power MOSFET transistor that shunts the power lines. Each receiver samples the signals from the sender with an isolation transformer that has its primary winding placed in series with the power lines. The master initiates a synchronizing pulse and places data in various timeslots. The slave follows with an initiating sync pulse followed by data in a group of timeslots. Edge-detection, rather than level-detection is used at the receivers for added immunity to supply and load changes. A double-pulse sync is used for special time slot reporting.

Claims

1. A powerline communication system, comprising:

a first station that continuously supplies operating power to a remotely located second station over a two-wire interconnecting circuit;

an isolation transformer with a primary winding connected in series with said two-wire interconnecting circuit and providing a baseband receiver signal output in a secondary winding;

a switching transistor connected across said two-wire interconnecting circuit and providing for an intermittent shunting of said operating power with pulse durations and pulse repetitions that produce a corresponding signal in said secondary winding;

an input multiplexer for receiving a plurality of data signals into a single sequence of patterned pulses connected to an input gate of the switching transistor; and

an output demultiplexer connected to receive a signal from said secondary winding of the isolation transformer and providing for a reconstruction of an original data presented on each of said plurality of data channels.

2. The system of claim 1, further including:

a transmitter isolation transformer connected between the switching transistor and the input multiplexer and providing for electrical isolation of the two-wire interconnecting circuit from the input multiplexer.

3. The system of claim 1, wherein:

the first station includes one each of the input multiplexer and switching transistor; and

the remotely located second station includes one each of the output demultiplexer and receiver isolation transformer in continuous communication with the master unit via said two-wire interconnecting circuit.

4. The system of claim 3, wherein:

the remotely located second station includes one each of the input multiplexer and switching transistor; and

the first station includes one each of the output demultiplexer and receiver isolation transformer in continuous communication with the slave unit via said two-wire interconnecting circuit;

wherein a continuously operating half-duplex communication channel is established without interference to a transfer of operating power from the first station to the remotely located second station.

5. A motion control system with powerline communication, comprising:

a programmable logic controller with a plurality of input and output channels programmed for motion control of a driver and stepper motor;

a master interface for continuously supplying operating power to said driver and stepper motor at a remote location over a two-wire interconnecting circuit;

a first isolation transformer located at said driver and stepper motor and including a primary winding connected in series with said two-wire interconnecting circuit and providing a baseband receiver signal output in a secondary winding;

a first switching transistor located at the master interface and connected across said two-wire interconnecting circuit and providing for an intermittent shunting of said operating power with pulse durations and pulse repetitions that produce a corresponding signal in said secondary winding;

a first input multiplexer located at the master interface and for receiving a plurality of data channels from the programmable logic controller and converting them into a single sequence of patterned pulses connected to an input gate of the first switching transistor; and

a first output demultiplexer located at said driver and stepper motor and connected to receive a signal from said secondary winding of the first isolation transformer and providing for a reconstruction of an original data presented on each of said plurality of data channels;

wherein the programmable logic controller is provided with two-wire control of the driver and stepper motor.

6. The system of claim 5, further comprising:

a second isolation transformer located at said master interface and including a primary winding connected in series with said two-wire interconnecting circuit and providing a baseband receiver signal output in a secondary winding;

a second switching transistor located at the driver and stepper motor and connected across said two-wire interconnecting circuit and providing for an intermittent shunting of said operating power with pulse durations and pulse repetitions that produce a corresponding signal in said secondary winding;

a second input multiplexer located at the driver and stepper motor and providing for sensor input data which is converted into a single sequence of patterned pulses connected to an input gate of the second switching transistor; and

a second output demultiplexer located at said master interface and connected to receive a signal from said secondary winding of the second isolation transformer and providing for a reconstruction of said sensor input data to then be input to the programmable logic controller;

wherein the programmable logic controller can control and verify the position of the driver and stepper motor.