Communication system for current-modulated data transmission via a current loop

Patent metadata

Field	Value
Publication number	US-11030137-B2
Application number	US-201716335772-A
Country	US
Kind code	B2
Filing date	Sep 22, 2017
Priority date	Sep 23, 2016
Publication date	Jun 8, 2021
Grant date	Jun 8, 2021

Abstract

A communication system for current-modulated transmission of data via a current loop—into which a master device and at least one slave device are looped. The at least one slave device has a switching means that is actuable by an evaluation and control unit and that is configured to short a current loop in the closed state, wherein the evaluation and control unit is configured to temporarily close and then reopen the switching means during a system configuration detection phase. An evaluation and control unit of the master device—is configured to detect when the at least one slave device is looped into the current loop.

First claim

The invention claimed is:

1. A communication system for current-modulated data transmission between a master device and at least one slave device, the communication system comprising:
a) a current loop;
b) a master device comprising:
a first evaluation and control unit;
a first switching means connected into the current loop and actuable by the first evaluation and control unit, which is configured to open and close the current loop for transmitting data;
an electrical current source connected to the current loop, which is configured to inject a constant quiescent current into the current loop;
a first current detection means connected into the current loop and connected to the first evaluation and control unit, the first evaluation and control unit being configured to evaluate the current detected by the first current detection means;

c) at least one slave device connected to the current loop and comprising:
a second evaluation and control unit;
a second switching means connected into the current loop and actuable by the second evaluation and control unit, which is configured to open and close the current loop for transmitting data;
a third switching means-actuable by the second evaluation and control unit, which is configured to short-circuit the current loop when in its closed state; wherein the second evaluation and control unit is configured to temporarily close and then reopen the third switching means during a system configuration detection phase, and wherein the first evaluation and control unit is configured to detect when the at least one slave device is connected to the current loop;
a second current detection means connected into the current loop and connected to the second evaluation and control unit, the second evaluation and control unit being configured to evaluate the current detected by the second current detection means;

(d) wherein at least one of:
(i) the master device has at least one first output that is controllable by the first evaluation and control unit; and
(ii) the at least one slave device has at least one second output that is controllable by the second evaluation and control unit

(e) wherein:
(i) the first evaluation and control unit of the master device is able to control the first switching means in a defined manner for generating a state change request signal;
(ii) the second evaluation and control is able to control the second switching means in a defined manner for generating a state change request signal;
(iii) the first evaluation and control unit of the master device is configured to transfer the first output into a safe state in response to a received state change request signal; and
(iv) the second evaluation and control is configured to transfer the second output into a safe state in response to a received state change request signal.

2. The communication system as claimed in claim 1 , wherein:
the first evaluation and control unit of the master device is configured to open the first switching means in response to a received state change request signal; and
the second evaluation and control unit is configured to open the second switching means in response to a received state change request signal.

3. The communication system as claimed in claim 1 , wherein:
the first evaluation and control unit is configured to keep the first in the safe state and at the same time to enable data transmission via the current loop; and
the second evaluation and control unit is configured to keep the second output in the safe state and at the same time to enable data transmission via the current loop.

4. A communication system for current-modulated data transmission between a master device and at least one slave device, the communication system comprising:
a) a current loop;
b) a master device comprising:
a first evaluation and control unit;
a first switching means connected into the current loop and actuable by the first evaluation and control unit, which is configured to open and close the current loop for transmitting data;
an electrical current source connected to the current loop, which is configured to inject a constant quiescent current into the current loop;
a first current detection means connected into the current loop and connected to the first evaluation and control unit, the first evaluation and control unit being configured to evaluate the current detected by the first current detection means;

c) at least one slave device connected to the current loop and comprising:
a second evaluation and control unit;
a second switching means connected into the current loop and actuable by the second evaluation and control unit, which is configured to open and close the current loop for transmitting data;
a third switching means-actuable by the second evaluation and control unit, which is configured to short-circuit the current loop when in its closed state; wherein the second evaluation and control unit is configured to temporarily close and then reopen the third switching means during a system configuration detection phase, and wherein the first evaluation and control unit is configured to detect when the at least one slave device is connected to the current loop;
a second current detection means connected into the current loop and connected to the second evaluation and control unit, the second evaluation and control unit being configured to evaluate the current detected by the second current detection means;

wherein:
the first evaluation and control unit is configured to close the first switching means and to inject predetermined system information into the current loop, during a system configuration detection phase; and
the second evaluation and control unit of the at least one slave device is configured to close the second and third switching means and to reopen the third switching means when it received the predetermined system information, during a system configuration detection phase.

5. A method for automatically detecting the configuration of a communication system for current-modulated data transmission between a master device and at least one slave device, the communication system comprising:
a) a current loop;
b) a master device comprising:
a first evaluation and control unit;
a first switching means connected into the current loop and actuable by the first evaluation and control unit, which is configured to open and close the current loop for transmitting data;
an electrical current source connected to the current loop, which is configured to inject a constant quiescent current into the current loop;
a first current detection means connected into the current loop and connected to the first evaluation and control unit, the first evaluation and control unit being configured to evaluate the current detected by the first current detection means;

c) at least one slave device connected to the current loop and comprising:
a second evaluation and control unit;
a second switching means connected into the current loop and actuable by the second evaluation and control unit, which is configured to open and close the current loop for transmitting data;
a third switching means-actuable by the second evaluation and control unit, which is configured to short-circuit the current loop when in its closed state; wherein the second evaluation and control unit is configured to temporarily close and then reopen the third switching means during a system configuration detection phase, and wherein the first evaluation and control unit is configured to detect when the at least one slave device is connected to the current loop;
a second current detection means connected into the current loop and connected to the second evaluation and control unit, the second evaluation and control unit being configured to evaluate the current detected

Assignees

• Phoenix Contact Gmbh & Co

Inventors

• Teutenberg Juergen
• Peter Henry
• Oster Viktor
• Säck Klaus-Peter

Classifications

• H04L12/403

  with centralised control, e.g. polling · CPC title

• G06F13/362

  with centralised access control · CPC title

• H04B3/54

  Systems for transmission via power distribution lines · CPC title

• G06F13/4022 Primary

  using switching circuits, e.g. switching matrix, connection or expansion network (G06F13/4009 takes precedence) · CPC title

• H04B14/026

  using pulse time characteristics modulation, e.g. width, position, interval · CPC title