SPE-BASED DEVICE ADAPTER FOR CONNECTING A NON-ETHERNET-COMPATIBLE FIELD DEVICE TO AN ETHERNET-BASED PROCESS CONTROL SYSTEM

An SPE-based device adapter for connecting a non-Ethernet-capable field device to an Ethernet-based process control system, includes: a first SPE-based communication interface which is adapted for receiving and transmitting Ethernet data frames via a two-wire Ethernet cable; a second communication interface which is adapted for receiving and transmitting data, according to a first communication protocol from and to a non-Ethernet-capable field device, wherein the first communication protocol is not an Ethernet-based communication protocol; and a first conversion unit which is adapted for converting data received via the second communication interface into Ethernet data frames for transmission via the first SPE-based communication interface, and to convert Ethernet data frames received via the first SPE-based communication interface into data for transmission via the second communication interface according to the first communication protocol.

FIELD

The invention relates to an SPE-based device adapter for connecting a non-Ethernet-capable field device to an Ethernet-based process control system which may in particular form part of an industrial automation system.

BACKGROUND

A process control system includes field devices such as sensors and actuators which communicate with a higher-level control device via a communication network. By now, Ethernet technology has been gaining more and more acceptance in industrial automation technology. So far, four-wire or eight-wire Ethernet cables have been used in communication networks to connect field devices to a higher-level Ethernet-capable control device. If non-Ethernet-capable field devices, such as, e.g., IO-Link-based field devices, are to be connected to a four-wire or eight-wire Ethernet cable, appropriate IO modules are used, which allow to connect non-Ethernet-capable field devices to the four-wire or eight-wire cable. More recently, it has become increasingly apparent in automation technology that single-pair Ethernet (SPE) technology will be employed, at least at the network level, according to which network subscribers are wired to one another via two-wire Ethernet cables. The SPE technology not only enables data exchange, but also power supply for the connected network subscribers, which is also known as Power over Dataline (PoDL).

SUMMARY

The present invention is based on the object to provide an SPE-based device adapter which allows to connect a non-Ethernet-capable field device to an Ethernet-based process control system via a two-wire Ethernet cable in a simple and cost-effective manner.

The above stated technical object is achieved by the features of claim1.

Accordingly, an SPE-based device adapter is provided for connecting a non-Ethernet-capable field device to an Ethernet-based process control system, the SPE-based device adapter having the following features:

a first SPE-based communication interface adapted for receiving and transmitting Ethernet data frames via a two-wire Ethernet cable;
a second communication interface adapted for receiving and transmitting data according to a first communication protocol from and to a non-Ethernet-capable field device, with the first communication protocol not being an Ethernet-based communication protocol;
a first conversion unit which is adapted for converting data received via the second communication interface into Ethernet data frames for transmission via the first SPE-based communication interface, and for converting Ethernet data frames received via the first SPE-based communication interface into data for transmission over the second communication interface according to the first communication protocol.

It should be noted that the SPE-based device adapter may in particular be in the form of a plug-in connector. In the context of the invention, the feature “Ethernet data frame” can be understood to mean, for example, that data can be transmitted according to an Ethernet communication protocol in Ethernet data frames via an SPE-based communication interface and a two-wire Ethernet cable.

In order to obtain a compact and flexible SPE-based device adapter, a third communication interface can be provided, which is adapted for receiving and transmitting data according to a second communication protocol from and to a non-Ethernet-capable field device. Again, the second communication protocol is not an Ethernet communication protocol. Furthermore, the second communication protocol is different from the first communication protocol. In addition, a second conversion unit is provided, which is adapted for converting data received via the third communication interface into Ethernet data frames for transmission via the first SPE-based communication interface, and for converting Ethernet data frames received via the first SPE-based communication interface into data for transmission via the third communication interface according to the second communication protocol. Furthermore, a control and/or evaluation device may be provided, which is adapted for detecting whether a non-Ethernet-capable field device is connected to the second or third communication interface. It is also adapted to connect the first or second conversion unit to the first SPE-based communication interface in response thereto.

According to an alternative embodiment, the SPE-based device adapter may have a third communication interface which is adapted for receiving and transmitting data according to a second communication protocol from and to a non-Ethernet-capable field device. The second communication protocol is not an Ethernet communication protocol and moreover differs from the first communication protocol. In addition, a fourth SPE-based communication interface is provided, which is adapted for receiving and transmitting Ethernet data frames via a two-wire Ethernet cable. Furthermore, a second conversion unit is provided, which is adapted for converting data received via the third communication interface into Ethernet data frames for transmission via the fourth SPE-based communication interface, and for converting Ethernet data frames received via the fourth SPE-based communication interface into data for transmission via the third communication interface according to the second communication protocol.

It should be noted here, that the first and second conversion units preferably are communication protocol conversion units which convert data according to an Ethernet communication protocol, i.e. Ethernet data frames, into data according to the first and/or second communication protocols, and vice versa.

Preferably, the second communication interface can be any of an IO-Link, HART, CAN, Profibus, RS-232, or RS-485 interface, and the first communication protocol can be any of an IO-Link, HART, CAN, Profibus, RS-232, or RS-485 communication protocol. However, any other non-Ethernet-based communication interfaces and non-Ethernet-based communication protocols are possible. Furthermore, the second communication interface may be any of a digital, analog, or optical communication interface.

Similarly, the third communication interface can be any of an IO-Link, HART, CAN, Profibus, RS-232, or RS-485 interface, and the second communication protocol can be any of an IO-Link, HART, CAN, Profibus, RS-232, or RS-485 communication protocol, with the second and third communication interfaces of the SPE-based device adapter being different from one another, as are the applied first and second communication protocols.

For powering the electronic components of the SPE-based device adapter, in particular the conversion units and the evaluation and/or control device, it is possible to employ the so-called Power over Data Line (PoDL) technology, in which case the SPE-based device adapter will be powered via a two-wire Ethernet cable, for example by enabling to connect, to the two-wire Ethernet cable, a network coupling element or a control device that provides the respective power.

The above-stated technical object is also achieved by the features of claim7.

Accordingly, an Ethernet-based process control system is provided, comprising the following features:

an SPE-based device adapter according to any one of claims1to6, to which a non-Ethernet-capable field device is connected;
a network coupling element, comprising:a port that is adapted for connecting a four-wire or eight-wire Ethernet cable;at least one SPE-based port that is adapted for connecting a two-wire Ethernet cable; anda conversion unit that is adapted for converting data arriving at the at least one SPE-based port into data for transmission via the port, and for converting data arriving at the port into data for transmission via the at least one SPE-based port; and
a higher-level control device that can be connected to the network coupling element via a four-wire or eight-wire Ethernet cable,
wherein the network coupling element is connectable to the SPE-based device adapter via a two-wire Ethernet cable.

DETAILED DESCRIPTION

FIG.1shows a single-pair Ethernet-based device adapter10, referred to as an SPE device adapter for short, which allows to connect at least one non-Ethernet-capable field device20to an Ethernet-based process control system1. The exemplary SPE-based device adapter10is preferably in the form of a plug-in connector which has a first SPE-based communication interface11that is adapted for receiving and transmitting Ethernet data frames via a two-wire Ethernet cable40. It should be noted that an Ethernet data frame is based on an Ethernet communication protocol. The SPE-based device adapter10can preferably be connected to a network coupling element50via the two-wire Ethernet cable40, i.e. an SPE cable. The network coupling element50is preferably a layer 2 Ethernet switch which may have a plurality of SPE-based ports51.1-51.n. In the illustrated example, the two-wire Ethernet cable40is connected to SPE-based port51.1. The network coupling element50furthermore has an Ethernet-based interface52to which either a four-wire or an eight-wire Ethernet cable60can be connected. In the present example it is assumed that the cable60is an eight-wire Ethernet cable. The eight-wire cable60can be used to connect the network coupling element50to a higher-level control device70, which is an Ethernet-capable programmable logic controller (PLC), for example. If the higher-level control device70has an SPE-based interface, the SPE-based device adapter10may as well be directly connected to the higher-level control device70via the two-wire Ethernet cable40. The exemplary network coupling element50preferably comprises a conversion unit55which is adapted for converting data arriving at the SPE-based port51.1, for example, into data for transmission via the eight-wire Ethernet port52, and vice versa.

Advantageously, the Ethernet-based process control system1may comprise the higher-level control device70, the SPE-based device adapter10or80, the network coupling element50, and non-Ethernet-capable field devices20,30.

The SPE-based device adapter10has a second communication interface12which is adapted for receiving and transmitting data from and to the non-Ethernet-capable field device20according to a first communication protocol. The non-Ethernet-capable field device20can be a sensor and an actuator having a communication interface21, for example. The second communication interface12and communication interface21of the non-Ethernet-capable field device20each support a first communication protocol that is not an Ethernet-based communication protocol. For example, the second communication interface12and the communication interface21of field device20may be any of an IO-Link, HART, CAN, Profibus, RS-232, or RS-485 interface. In the present case, the second communication interface12and the interface21of field device20are an IO-Link interface by way of example, which are interconnected via a corresponding cable90in the illustrated example. Thus, the non-Ethernet-capable field device20is a field device which uses the IO-Link communication protocol. In order to be able to connect the non-Ethernet-capable field device20to the Ethernet-based process control system1, the SPE-based device adapter includes a conversion unit15which preferably is in the form of a communication protocol converter. Accordingly, the conversion unit15is adapted for converting data received from the field device20via the second communication interface12which is implemented as an IO-Link interface, for example, into Ethernet data frames for transmission via the first SPE-based communication interface11, and to convert Ethernet data frames received via the first SPE-based communication interface11from the network coupling element50or from the higher-level control device70into data for transmission via the second communication interface12according to the first communication protocol, here the IO-Link communication protocol.

In order to expand the field of application and the flexibility of the SPE-based device adapter10and to achieve scalability, a third communication interface13can be provided, which is adapted for receiving and transmitting data according to a second communication protocol from and to a non-Ethernet-capable field device30, the second communication protocol not being an Ethernet communication protocol, and with the first and second communication protocols being different from each other. For example, the third communication interface may support the Profibus communication protocol as the second communication protocol, in which case the non-Ethernet-capable field device30is in the form of a Profibus-capable field device30having a Profibus-based communication interface31. Field device30can be connected to the third communication interface13via the Profibus-based communication interface31using a Profibus-based connection cable91. The SPE-based device adapter10may furthermore have a fourth SPE-based communication interface14. In addition, a second conversion unit may be implemented in the SPE-based device adapter10, which is adapted for converting data received from the field device30via the third communication interface into Ethernet data frames for transmission via the fourth SPE-based communication interface14, and for converting Ethernet data frames received via the fourth SPE-based communication interface14into data for transmission via the third communication interface13according to the second communication protocol, i.e. the Profibus communication protocol in the present example.

If, for example, the device adapter10comprises the fourth SPE-based communication interface, the second conversion unit16and the third communication interface13, in practice, only one field device, e.g. field device20or field device30, will preferably be connected to the Ethernet-based process control system1or to the network coupling element50via the device adapter10, for example via the two-wire Ethernet cable40. However, it is also conceivable to simultaneously connect both field devices20and30to the network coupling element50via the SPE-based device adapter10, for example. For this purpose, a further two-wire Ethernet cable (not shown) can be used to connect the fourth SPE-based communication interface14to the SPE-based port51.2of network coupling element50, for example.

FIG.2shows an alternative SPE-based device adapter80which, similar to SPE device adapter10, can have the following features: a first SPE-based communication interface81which is adapted for receiving and transmitting Ethernet data frames via a two-wire Ethernet cable, for example cable40; a communication interface82which is adapted for receiving and transmitting data according to a first communication protocol from and to a non-Ethernet-capable field device, for example field device20, with the first communication protocol not being an Ethernet-based communication protocol; a first conversion unit86which is adapted for converting data received via the second communication interface82into Ethernet data frames for transmission via the first SPE-based communication interface81, and for converting Ethernet data frames received via the first SPE-based communication interface81into data for transmission via the second communication interface82according to the first communication protocol. In the present example, the first communication protocol may again be the IO-Link communication protocol. In the exemplary SPE-based device adapter80, the second communication interface82will thus be adapted to receive and transmit data according to the IO-Link communication protocol.

According to an advantageous embodiment, the SPE-based device adapter80can also be used to connect at least two different non-Ethernet-capable field devices to the Ethernet-based process control system1.

For this purpose, the SPE-based device adapter80furthermore has a third communication interface83which is adapted for receiving and transmitting data according to a second communication protocol from and to a non-Ethernet-capable field device, for example field device30. The second communication protocol may be the Profibus communication protocol, for example, in which case the field device30can be connected to the third communication interface83via connection cable91, for example. The second communication protocol is not an Ethernet communication protocol and is different from the first communication protocol. The SPE-based device adapter80may comprise a second conversion unit85which is adapted for converting data received via the third communication interface83into Ethernet data frames for transmission via the first SPE-based communication interface81, and for converting Ethernet data frames received via the first SPE-based communication interface into data for transmission over the third communication interface83according to the second communication protocol. Thus, the SPE-based device adapter80acts as a kind of gateway, i.e. as a protocol converter. Furthermore, the SPE-based device adapter80may comprise a control and/or evaluation device84, for example in the form of a microcontroller. The control and/or evaluation device84is adapted to detect whether a non-Ethernet-capable field device is connected to the second communication interface82or to the third communication interface. The control and/or evaluation device84is furthermore adapted to connect the first conversion unit86or the second conversion unit85to the first SPE-based communication interface81, depending on whether a non-Ethernet-capable field device is connected to the second or to the third communication interface. For this purpose, the control and/or evaluation device84may drive a switching element87accordingly.

For powering in particular the conversion unit15and, if provided, the conversion unit16, it is possible to use what is known as the Power over Data Line technology. For example, if the network coupling element50has its own power supply unit, PoDL technology makes it possible to power the SPE-based device adapter10via the two-wire Ethernet cable40. Similarly, the SPE-based device adapter80and in particular the control and/or evaluation device84and the two conversion units85and86can also be powered via the power supply unit of the network coupling element50, for example.

Some exemplary aspects of the invention are summarized again below.

Accordingly, a process control system1is provided, which is shown inFIG.1by way of example and which can have the following features:

an SPE-based device adapter10or80as discussed above by way of example, to which a non-Ethernet-capable field device20and/or30is connected;
a network coupling element50which has:a port52, adapted for connecting a four-wire or eight-wire Ethernet cable60;at least one SPE-based port51.1-51.n, adapted for connecting a two-wire Ethernet cable40; anda conversion unit which is adapted for converting data arriving at the at least one SPE-based port51.1-51.ninto data for transmission via port52, and for converting data arriving at port52into data for transmission via the at least one SPE-based port51.1-51.n; and
a higher-level control device70that can be connected to the network coupling element50via a four-wire or eight-wire Ethernet cable60;
wherein the network coupling element50can be connected to the SPE-based device adapter10,80via a two-wire Ethernet cable40.

LIST OF REFERENCE NUMERALS

1Process control system
10SPE-based device adapter
11First SPE-based communication interface
12Second communication interface
13Third communication interface
14Fourth SPE-based communication interface
15First conversion unit, in particular for communication protocol conversion,
16Second conversion unit, in particular for communication protocol conversion
20Non-Ethernet-capable field device, in particular sensor or actuator
21Communication interface
30Non-Ethernet-capable field device, in particular sensor or actuator
31Communication interface
40Two-wire Ethernet cable
50Network coupling element, in particular layer 2 Ethernet switch
51.1-nSPE-based port
52Port for connecting a four-wire or eight-wire Ethernet cable
55Conversion unit
60Four-wire or eight-wire Ethernet cable
70Higher-level control device, e.g. Ethernet-capable PLC
80SPE-based device adapter
81First SPE-based communication interface
82Second communication interface
83Third communication interface
84Evaluation and/or control device, e.g. microcontroller
85First conversion unit, in particular for communication protocol conversion,
86Second conversion unit, in particular for communication protocol conversion
87Controllable switching element
90Connection cable
91Connection cable