DE102023000951A1 - Bus system and method for operating a bus system - Google Patents

Abstract

The invention relates to a bus system, comprising a feed module (10), a consumer module (20) and a data cable (30), which connects the feed module (10) to the consumer module (20), the data cable (30) having at least one first wire ( 31), a second wire (32), a third wire (33) and a fourth wire (34), and wherein the feed module (10) has at least one DC voltage source (105) which supplies a feed voltage (UE), whereby the The feed module (10) has a first switch (11), by means of which the feed voltage (UE) supplied by the DC voltage source (105) can be applied between the first wire (31) and the second wire (32), and the consumer module (20). has a detection unit (25) which monitors a first voltage (U1) present between the first wire (31) and the second wire (32), and the consumer module (20) has a control unit (27), in particular for controlling a drive, which can be supplied by a supply voltage source (29) which supplies a supply voltage (UV), and wherein the detection unit (25) has a controllable switching unit (23) which separates the control unit (27) from the supply voltage source (29) when the Detection unit (25) detects a switch-off signal when monitoring the first voltage (U1). The invention relates to a method for operating a bus system according to the invention.

Description

The invention relates to a bus system which includes a feed module, a consumer module and a data cable which connects the feed module to the consumer module, the data cable having several wires. The invention also relates to a method for operating a bus system according to the invention.

Today's automation systems have bus systems for transmitting data between feed modules and consumer modules. Consumer modules, which are also referred to as field devices, have, for example, a control unit with power electronics for controlling an electric drive. A feed module is connected to a consumer module using a data cable, which has several wires for transmitting data signals.

An example of a generic bus system is, among others, EtherCat. In addition to the transmission of data, such a bus system in the “Power Over EtherCAT” version also offers the option of providing two independent voltage sources for consumer modules.

An electric drive in such an automation system can be transferred to a safe operating state using a “Safe Torque Off” / STO function. Such an STO signal can be transmitted, for example, via separate signal lines and prevents the generation of torque on the electric drive, for example by deactivating the power supply to gate drivers of the power electronics in the control unit. The disadvantage here is additional and complex wiring of the signal lines.

Alternatively, an STO signal can be transmitted via the bus system as a secure data record. The STO signal is evaluated in the consumer module and generation of torque on the electric drive is safely deactivated. Such a solution reduces the wiring effort, but requires extensive drive development and commissioning according to safety guidelines.

From the document DE 10 2016 109 450 A1 a bus system is known which includes a feed module, a consumer module and a data cable connecting the feed module to the consumer module. The data cable has several wires for transmitting data signals and also allows the transmission of supply voltages.

From the DE 10 2015 116 800 B3 an input/output module for a bus system is known, which includes two DC voltage supplies. The DC voltage supplies are each connected to an electrical contact via an inductive assembly.

From the DE 10 2015 116 802 B3 A bus system is known which includes a data cable with two pairs of wires and an input/output module. The bus system includes two DC voltage supplies.

The invention is based on the object of developing a bus system and a method for operating a bus system.

The object is achieved according to the invention by a bus system with the features specified in claim 1. Advantageous refinements and further developments are the subject of the subclaims. The object is also achieved by a method for operating a bus system according to the invention with the features specified in claim 6. Advantageous refinements and further developments are the subject of the subclaims.

A bus system according to the invention comprises a feed module, a consumer module and a data cable which connects the feed module to the consumer module. The data cable has at least a first wire, a second wire, a third wire and a fourth wire, and the feed module has at least one DC voltage source which supplies a feed voltage. The feed module has a first switch, by means of which the feed voltage supplied by the DC voltage source can be applied between the first wire and the second wire. The consumer module has a detection unit which monitors a first voltage present between the first wire and the second wire. The consumer module has a control unit, in particular for controlling a drive, which can be supplied by a supply voltage source that supplies a supply voltage. The detection unit has a controllable switching unit which isolates the control unit from the supply voltage source when the detection unit detects a switch-off signal when monitoring the first voltage.

By means of the bus system according to the invention, an STO signal can be easily and safely transmitted as a switch-off signal from the feed module to the control unit of the consumer module, thereby reliably preventing the generation of torque on the electric drive. To transmit the switch-off signal, they are available The cores of the data cable are used, so there is no additional wiring required. Furthermore, development costs and installation costs are relatively low.

According to an advantageous development, the feed module has a second switch, by means of which the feed voltage supplied by the DC voltage source can be applied between the third wire and the fourth wire, and the detection unit monitors a second voltage present between the third wire and the fourth wire. The switching unit disconnects the control unit from the supply voltage source when the detection unit detects a switch-off signal while monitoring the second voltage.

During normal operation of the bus system, the first switch and the second switch are closed. The feed module thus comprises two independent voltage sources for supplying components of the consumer module. In the consumer module, the first voltage applied between the first wire and the second wire and the second voltage applied between the third wire and the fourth wire are available. A switch-off signal can be transmitted via both voltage sources. This redundancy advantageously increases security.

According to an advantageous development, the detection unit detects a switch-off signal when the first voltage falls below a lower limit and/or when the second voltage falls below a lower limit. When the first switch is opened, the first voltage drops. When the second switch is opened, the second voltage drops. Such a voltage drop can be detected relatively quickly and reliably.

According to a preferred embodiment, the feed module has a data interface which is connected to the first wire and the second wire via a transformer and at least one capacitor in order to send a differential data signal to the first wire and the second wire. Likewise, the data interface is connected to the third wire and the fourth wire via a transformer and at least one capacitor in order to receive a differential data signal from the third wire and the fourth wire. The feed module is therefore designed for data transmission in full duplex mode. The data interface is galvanically isolated from the wires of the data cable.

According to a preferred embodiment, the consumer module has a data interface which is connected to the first wire and the second wire via a transformer and at least one capacitor in order to receive a differential data signal from the first wire and the second wire. Likewise, the data interface is connected to the third wire and the fourth wire via a transformer and at least one capacitor in order to send a differential data signal to the third wire and the fourth wire. The consumer module is therefore designed for data transmission in full duplex mode. The data interface is galvanically isolated from the wires of the data cable.

According to a method according to the invention for operating a bus system according to the invention, a switch-off signal is sent from the feed module to the first wire and the second wire. The first voltage present between the first wire and the second wire is monitored by the detection unit. If the switch-off signal is detected when monitoring the first voltage, the switching unit is controlled in such a way that the control unit is separated from the supply voltage source. Using the method according to the invention, an STO signal is transmitted simply and safely from the feed module to the control unit of the consumer module as a switch-off signal. This reliably prevents the generation of torque on the electric drive.

According to an advantageous development, the feed module has a second switch, by means of which the feed voltage supplied by the DC voltage source can be applied between the third wire and the fourth wire. The feed module sends a switch-off signal to the third wire and the fourth wire. The second voltage present between the third wire and the fourth wire is monitored by the detection unit. If the switch-off signal is detected when monitoring the second voltage, the switching unit is controlled in such a way that the control unit is separated from the supply voltage source. A switch-off signal can therefore be transmitted to the detection unit of the consumer module via two voltage sources. This redundancy advantageously increases security.

According to an advantageous embodiment, a switch-off signal is sent to the first wire and the second wire by disconnecting the DC voltage source from the first wire and/or from the second wire by opening the first switch. A switch-off signal is detected by the detection unit when the first voltage falls below a lower limit value. According to an advantageous embodiment, a switch-off signal is sent to the third wire and the fourth wire by the DC voltage source is separated from the third wire and the fourth wire by opening the second switch. A switch-off signal is detected by the detection unit when the second voltage falls below a lower limit value.

During normal operation of the bus system, the first switch and the second switch are closed. When the first switch is opened, the first voltage drops. When the second switch is opened, the second voltage drops. Such a voltage drop is detected relatively quickly and reliably by the detection unit.

According to an advantageous embodiment, a switch-off signal is sent to the first wire and the second wire by coupling a signal with a defined signal frequency into the first wire and the second wire. A switch-off signal is detected by the detection unit when a signal with the signal frequency is detected in the first voltage. According to an advantageous embodiment, a switch-off signal is sent to the third wire and the fourth wire by coupling a signal with a defined signal frequency into the third wire and the fourth wire. A switch-off signal is detected by the detection unit when a signal with the signal frequency is detected in the second voltage.

By coupling the switch-off signal as a signal with a defined signal frequency, the first voltage and the second voltage continue to be available to supply components of the consumer module even after the switch-off signal has been sent. The consumer module has an electronic circuit, for example in the form of a bandpass, from which the signal with the defined signal frequency is recognized.

According to an advantageous embodiment, a switch-off signal is sent to the first wire and the second wire by briefly disconnecting the DC voltage source from the first wire and/or from the second wire by opening and closing the first switch. A switch-off signal is detected by the detection unit when a brief interruption in the first voltage is detected. According to an advantageous embodiment, a switch-off signal is sent to the third wire and the fourth wire by briefly disconnecting the DC voltage source from the third wire and/or from the fourth wire by opening and closing the second switch. A switch-off signal is detected by the detection unit when a brief interruption in the second voltage is detected.

By briefly opening and closing one of the switches, the first voltage and the second voltage continue to be available to supply components of the consumer module even after the switch-off signal has been sent. The consumer module has an electronic circuit, for example in the form of a high pass, which detects a brief interruption in the first voltage and the second voltage.

According to an advantageous development, the control unit has an evaluation unit which monitors the first voltage present between the first wire and the second wire and the second voltage present between the third wire and the fourth wire. If the switch-off signal is detected when monitoring the first voltage and/or when monitoring the second voltage, the control unit is disconnected from the supply voltage source. In addition to the detection unit, the control unit also monitors the voltages present between the wires and disconnects the control unit from the supply voltage source when the switch-off signal is detected. This additional redundancy further increases security.

The invention is not limited to the combination of features of the claims. For the person skilled in the art, further sensible combination options of claims and/or individual claim features and/or features of the description and/or the figures arise, in particular from the task and/or the task posed by comparison with the prior art.

• 1: eine schematische Darstellung eines Bussystems.

The invention will now be explained in more detail using illustrations. The invention is not limited to the exemplary embodiments shown in the figures. The illustrations only represent the subject matter of the invention schematically. It shows:

• 1 : a schematic representation of a bus system.

In the 1 A bus system is shown schematically. The automation system includes a feed module 10, a consumer module 20 and a data cable 30. The data cable 30 connects the feed module 10 to the consumer module 20. The bus system is designed, for example, as EtherCat or as Power over EtherCat.

The data cable 30 has a first wire 31, a second wire 32, a third wire 33 and a fourth wire 34. The first wire 31 and the second wire 32 form a first pair of wires via which differential data signals can be transmitted. The third wire 33 and the fourth wire 34 form a two th pair of wires via which differential data signals can also be transmitted.

The feed module 10 has a data interface 123. The data interface 123 is connected to the first wire 31 via a transformer 125 and a capacitor 127. The data interface 123 is connected to the second wire 32 via the transformer 125 and a further capacitor 127. The data interface 123 is set up to send a differential data signal to the first wire 31 and the second wire 32.

The data interface 123 of the feed module 10 is connected to the third wire 33 via a further transformer 125 and a further capacitor 127. The data interface 123 is connected to the fourth wire 34 via the transformer 125 and a further capacitor 127. The data interface 123 is set up to receive a differential data signal from the third wire 33 and the fourth wire 34.

The consumer module 20 also has a data interface 123. The data interface 123 is connected to the first wire 31 via a transformer 125 and a capacitor 127. The data interface 123 is connected to the second wire 32 via the transformer 125 and a further capacitor 127. The data interface 123 is set up to receive a differential data signal from the first wire 31 and the second wire 32.

The data interface 123 of the consumer module 20 is connected to the third wire 33 via a further transformer 125 and a further capacitor 127. The data interface 123 is connected to the fourth wire 34 via the transformer 125 and a further capacitor 127. The data interface 123 is set up to send a differential data signal to the third wire 33 and the fourth wire 34.

The feed module 10 has a DC voltage source 105, which supplies a feed voltage UE. The feed module 10 has a first switch 11. When the first switch 11 is closed, the DC voltage source 105 is connected to the first wire 31 via an inductor 121 and connected to the second wire 32 via a further inductor 121. When the first switch 11 is closed, the feed voltage UE supplied by the DC voltage source 105 is present as the first voltage U1 between the first wire 31 and the second wire 32.

The feed module 10 also has a second switch 12. When the second switch 12 is closed, the DC voltage source 105 is connected to the third wire 33 via an inductor 121 and connected to the fourth wire 34 via a further inductor 121. When the second switch 12 is closed, the feed voltage UE supplied by the DC voltage source 105 is present as the second voltage U2 between the third wire 33 and the fourth wire 34.

The consumer module 20 has a control unit 27. The control unit 27 is, for example, an inverter or a frequency converter and is used to control an electric drive. The control unit 27 is connected to a supply voltage source 29, which supplies a supply voltage UV, and can be supplied with electrical energy from the supply voltage source 29.

The consumer module 20 has a detection unit 25. The detection unit 25 is connected to the first wire 31 via an inductor 121 and connected to the second wire 32 via a further inductor 121. The detection unit 25 monitors the first voltage U1 present between the first wire 31 and the second wire 32.

The detection unit 25 is further connected to the third wire 33 via an inductor 121 and connected to the fourth wire 34 via a further inductor 121. The detection unit 25 monitors the second voltage U2 present between the third wire 33 and the fourth wire 34.

The detection unit 25 has a controllable switching unit 23. In the present case, the switching unit 23 comprises a first transistor 41 and a second transistor 42. In the present case, the transistors 41, 42 are designed as normally-off transistors, in particular as bipolar transistors. Alternatively, field effect transistors or relays, for example, are also conceivable.

A base of the first transistor 41 is connected to the first wire 31. An emitter of the first transistor 41 is connected to the second wire 32. A base of the second transistor 42 is connected to the third wire 33. An emitter of the second transistor 42 is connected to the fourth wire 34. If a voltage is present between the base and the emitter of a transistor 41, 42, the corresponding transistor 41, 42 is conductive. If there is no voltage between the base and the emitter of a transistor 41, 42, the corresponding transistor 41, 42 is blocking.

The transistors 41, 42 of the switching unit 23 are electrically connected in series and form a circuit with the control unit 27 and the supply voltage source 29. If the first transistor 41 and the second transistor 42 are conducting, the circuit in question is closed and the circuit from the Supply voltage UV supplied by supply voltage source 29 is present at control unit 27. If the first transistor 41 or the second transistor 42 is off, the circuit in question is interrupted and the supply voltage UV is not present at the control unit 27.

When the first switch 11 of the feed module 10 is closed, the feed voltage UE supplied by the DC voltage source 105 is present as the first voltage U1 between the base and the emitter of the first transistor 41. The first transistor 41 is therefore conductive. When the first switch 11 of the feed module 10 is open, there is no voltage between the base and the emitter of the first transistor 41. The first transistor 41 is therefore blocking.

When the second switch 12 of the feed module 10 is closed, the feed voltage UE supplied by the DC voltage source 105 is present as the second voltage U2 between the base and the emitter of the second transistor 42. The second transistor 42 is therefore conductive. When the second switch 12 of the feed module 10 is open, there is no voltage between the base and the emitter of the second transistor 42. The second transistor 42 is therefore blocking.

A turn-off signal is sent to the first wire 31 and the second wire 32 by opening the first switch 11. The switch-off signal is detected by the detection unit 25 as a voltage drop in the first voltage U1 as soon as the first voltage U1 falls below a lower limit value. The first transistor 41 then turns off. The switching unit 23 thus separates the control unit 27 from the supply voltage source 29 when the detection unit 25 detects the switch-off signal when monitoring the first voltage U1.

A turn-off signal is sent to the third wire 33 and the fourth wire 34 by opening the second switch 12. The switch-off signal is detected by the detection unit 25 as a voltage drop in the second voltage U2 as soon as the second voltage U2 falls below a lower limit value. The second transistor 42 then turns off. The switching unit 23 thus separates the control unit 27 from the supply voltage source 29 when the detection unit 25 detects the switch-off signal when monitoring the second voltage U2.

Reference symbol list

10

Feed module

11

first switch

12

second switch

20

Consumer module

23

Switching unit

25

Detection unit

27

Control unit

29

Supply voltage source

30

Data cable

31

first wire

32

second wire

33

third wire

34

fourth wire

41

first transistor

42

second transistor

105

DC voltage source

121

inductance

123

Data interface

125

transformer

127

capacitor

U.E

supply voltage

U1

first tension

U2

second voltage

UV

Supply voltage

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102016109450 A1 [0006]
• DE 102015116800 B3 [0007]
• DE 102015116802 B3 [0008]

Claims (11)

Bus system, comprising a feed module (10), a consumer module (20) and a data cable (30) which connects the feed module (10) to the consumer module (20), the data cable (30) having at least one first wire (31). second wire (32), a third wire (33) and a fourth wire (34), and wherein the feed module (10) has at least one DC voltage source (105) which supplies a feed voltage (UE), characterized in that the feed module (10) has a first switch (11), by means of which the feed voltage (UE) supplied by the DC voltage source (105) can be applied between the first wire (31) and the second wire (32), and that the consumer module (20) has a Detection unit (25) which monitors a first voltage (U1) present between the first wire (31) and the second wire (32), and that the consumer module (20) has a control unit (27), in particular for controlling a drive , which can be supplied by a supply voltage source (29) that supplies a supply voltage (UV), and that the detection unit (25) has a controllable switching unit (23) which separates the control unit (27) from the supply voltage source (29), if the detection unit (25) detects a switch-off signal when monitoring the first voltage (U1). bus system Claim 1 , characterized in that the feed module (10) has a second switch (12), by means of which the feed voltage (UE) supplied by the DC voltage source (105) can be applied between the third wire (33) and the fourth wire (34), and that the detection unit (25) monitors a second voltage (U2) present between the third wire (33) and the fourth wire (34), and that the switching unit (23) disconnects the control unit (27) from the supply voltage source (29), if the detection unit (25) detects a switch-off signal when monitoring the second voltage (U2). Bus system according to one of the preceding claims, characterized in that the detection unit (25) detects a switch-off signal when the first voltage (U1) falls below a lower limit and/or when the second voltage (U2) falls below a lower limit. Bus system according to one of the preceding claims, characterized in that the feed module (10) has a data interface (123) which has a transformer (125) and at least one capacitor (127) with the first wire (31) and the second wire (32 ) is connected to send a differential data signal to the first wire (31) and the second wire (32), and which is connected via a transformer (125) and at least one capacitor (127) to the third wire (33) and the fourth Wire (34) is connected to receive a differential data signal from the third wire (33) and the fourth wire (34). Bus system according to one of the preceding claims, characterized in that the consumer module (20) has a data interface (123) which is connected via a transformer (125) and at least one capacitor (127) to the first wire (31) and the second wire (32 ) is connected to receive a differential data signal from the first wire (31) and the second wire (32), and which is connected via a transformer (125) and at least one capacitor (127) to the third wire (33) and the fourth Wire (34) is connected to send a differential data signal to the third wire (33) and the fourth wire (34). Method for operating a bus system according to one of the preceding claims, characterized in that a switch-off signal is sent from the feed module (10) to the first wire (31) and the second wire (32); the first voltage (U1) present between the first wire (31) and the second wire (32) is monitored by the detection unit (25); and the switching unit (23) is controlled in such a way that the control unit (27) is separated from the supply voltage source (29) when the switch-off signal is detected when monitoring the first voltage (U1). Procedure according to Claim 6 , characterized in that the feed module (10) has a second switch (12), by means of which the feed voltage (UE) supplied by the DC voltage source (105) can be applied between the third wire (33) and the fourth wire (34), and that a switch-off signal is sent from the feed module (10) to the third wire (33) and the fourth wire (34); from the detection unit (25) between the third wire (33) and the fourth wire (34). second voltage (U2) is monitored; and the switching unit (23) is controlled in such a way that the control unit (27) is separated from the supply voltage source (29) when the switch-off signal is detected when monitoring the second voltage (U2). Procedure according to one of the Claims 6 until 7 , characterized in that a switch-off signal is sent to the first wire (31) and the second wire (32) by disconnecting the DC voltage source (105) from the first wire (31) and / or from the by opening the first switch (11). second wire (32) is separated, and that a switch-off signal is detected by the detection unit (25) when the first voltage (U1) falls below a lower limit value; and/or that a switch-off signal is sent to the third wire (33) and the fourth wire (34) by disconnecting the DC voltage source (105) from the third wire (33) and from the fourth wire (105) by opening the second switch (12). 34) is separated, and that a switch-off signal is detected by the detection unit (25) when the second voltage (U2) falls below a lower limit value. Procedure according to one of the Claims 6 until 8th , characterized in that a switch-off signal is sent to the first wire (31) and the second wire (32) by coupling a signal with a defined signal frequency into the first wire (31) and the second wire (32), and that A switch-off signal is detected by the detection unit (25) when a signal with the signal frequency is detected in the first voltage (U1); and/or that a switch-off signal is sent to the third wire (33) and the fourth wire (34) by coupling a signal with a defined signal frequency into the third wire (33) and the fourth wire (34), and that from the detection unit (25) detects a switch-off signal when a signal with the signal frequency is detected in the second voltage (U2); Procedure according to one of the Claims 6 until 9 , characterized in that a switch-off signal is sent to the first wire (31) and the second wire (32) by briefly disconnecting the direct voltage source (105) from the first wire (31) and/or by opening and closing the first switch (11). or is separated from the second wire (32), and that a switch-off signal is detected by the detection unit (25) when a brief interruption in the first voltage (U1) is detected; and/or that a switch-off signal is sent to the third wire (33) and the fourth wire (34) by briefly disconnecting the DC voltage source (105) from the third wire (33) and/or by opening and closing the second switch (12). is separated from the fourth wire (34), and that a switch-off signal is detected by the detection unit (25) when a brief interruption in the second voltage (U2) is detected. Procedure according to one of the Claims 6 until 10 , characterized in that the control unit (27) has an evaluation unit which has the first voltage (U1) present between the first wire (31) and the second wire (32) and that between the third wire (33) and the fourth wire ( 34) monitors the applied second voltage (U2), and that the control unit (27) is separated from the supply voltage source (29) if the switch-off signal is received when monitoring the first voltage (U1) and / or when monitoring the second voltage (U2). is detected.

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