MODULE UNIT FOR CONNECTING A DATA BUS PARTICIPANT

Description

1. Field of the invention

[0001] The present invention relates to a module unit for connecting a data bus subscriber to a local bus, in particular during operation of the local bus. 2. State of the art

[0002] Modular units for connecting a data bus device to a local bus are typically used in automation systems. Automation systems are primarily used to control industrial plants, buildings, and means of transport. Controlling an automation system usually requires several sensors and actuators. These monitor and control the process executed by the system. The various sensors and actuators in an automation system are often referred to as automation devices.

[0003] These automation devices can either be connected directly to a controller of the automation system or can first be connected to input and output modules, often referred to as I / O modules. These can then be connected directly to the controller. The automation devices can either be integrated directly into the I / O modules or can be connected to them via cable or wirelessly.

[0004] The control of an automation system is usually accomplished with the help of one or more programmable logic controllers (PLCs). The PLCs can be arranged hierarchically or decentrally within an automation system. PLCs come in different performance classes, so that they can perform different control and regulation functions depending on their computing and memory capacity. In the simplest case, a PLC has inputs, outputs, an operating system (firmware), and an interface through which a user program can be loaded. The user program specifies how the outputs are to be switched depending on the inputs. The inputs and outputs can be connected to the automation devices and / or the I / O modules, and the process carried out by the automation system can be monitored and controlled based on the logic stored in the user program.The process is monitored by sensors, and controlled by actuators. The controller can also be referred to as a central controller or central processing unit and is responsible for controlling at least one automation device or I / O module connected to the controller.

[0005] However, directly connecting the automation devices to the at least one controller or the I / O modules to the at least one controller using parallel wiring—i.e., a separate cable is routed from each automation device or each I / O module to the higher-level controller—is very complex. Especially with increasing levels of automation in an automation system, the cabling effort required for parallel wiring increases. This entails considerable effort during configuration, installation, commissioning, and maintenance.

[0006] Therefore, bus systems are commonly used in automation technology today to connect automation devices or I / O modules to the controller. To further simplify the connection of individual automation devices or I / O modules to the bus system, individual groups of automation devices or I / O modules are often first connected to each other using a specialized local bus to form a local bus system. Subsequently, at least one participant of this local bus is connected to the bus system connected to the controller. The local bus system may differ from the bus system used to establish the connection to the controller.

[0007] The participant in a group of local bus participants that is connected to the controller's bus system is often referred to as the local bus master. Alternatively, the term head station of the local bus system is also used. This local bus master can contain additional logic, circuits or functionalities than other local bus participants that are necessary for connecting to the controller's bus system. The local bus master itself can also contain a PLC. This participant can also have logic and circuits for converting between the two bus systems. The local bus master can therefore also be designed as a gateway or bus converter and ensures that data in the format of one bus system is converted into the format of the local bus system and vice versa. In most cases, but not necessarily, the local bus master is specialized in connecting the local bus to the higher-level bus.

[0008] The local buses used are usually tailored to the specific application requirements of the automation devices or I / O modules or take their specific hardware design into account. The groups of automation devices or I / O modules of the local bus system usually form a subgroup of the automation system for executing a specific task within the process executed by the automation system. The data exchanged on the buses for the process is also frequently referred to as local bus data or process data, because this data contains information for regulating or controlling the process executed by the automation system. This data can include, among other things, measurement data, control data, status data, and / or other information. Depending on the bus protocol used, other data can be prefixed to this data. (English) header) or appended (English)Tail). This other data can contain information about the data itself, or information about internal communication on the local bus. A variety of different information is known which can be prefixed to or appended to the process data depending on the bus protocol used. The local bus nodes connected to a local bus can also be referred to as data bus nodes because they exchange data on the local bus. A data bus node can be used to control or monitor a process, in particular by outputting control signals, e.g. to actuators, and / or by receiving measurement signals, e.g. from sensors. The data bus node converts the control signals and / or measurement signals into process data for the local bus or vice versa. The data bus nodes can also be referred to as local bus nodes.

[0009] An example of a local bus is a ring bus, which is a specialized form of local bus, as known, for example, from US 5,472,347 A. In a ring bus, the data bus devices, for example the automation devices or I / O modules, are each connected to their directly adjacent data bus devices, and data is forwarded sequentially from one data bus device to the next. Data is therefore not sent to all data bus devices at the same time, but rather sequentially, with each data bus device receiving data from its upstream data bus device and forwarding it to its downstream data bus device. Between receiving the data and forwarding it, the data bus device can process the received data. When the data has reached the last data bus device in the series, the last data bus device returns the data sequentially to the first data bus device.The return can occur either through all data bus nodes or bypass them using a bypass line. The ring bus thus has a downstream and upstream data stream. Data in a ring bus is usually transmitted in the form of data packets that pass through all data bus nodes.

[0010] In a closed ring bus arrangement, each slot on the local bus must be occupied by a data bus device so that data can be forwarded sequentially from one data bus device to the next. If a slot is not occupied by a data bus device, the bus, or rather the downstream and / or upstream data flow, is interrupted, and forwarding or redirecting of data is no longer possible. Removing a correspondingly plugged data bus device during operation would also immediately interrupt the bus.

[0011] Patent DE 10 2013 100603 B3 discloses a circuit arrangement for connecting a bus device to a bus, in particular a system for connecting a data bus device to a local ring bus. Another prior art network with a ring topology is described in patent application US 2005 / 111372 A1.

[0012] Based on this, it is the object of the present invention to provide an improved module unit which enables a local bus to continue operating even when one or more data bus participants are removed, rather than being interrupted. 3. Summary of the invention

[0013] This object is achieved with a modular unit according to the independent claim. Advantageous embodiments are described in the subclaims.

[0014] The modular unit according to the invention for connecting a data bus subscriber to a local ring bus has a first input interface and a first output interface that can be connected to the local bus. This means that the first input interface and a first output interface are adapted to be connected to the local bus. The modular unit according to the invention further has a first data connection interface that can be connected to the data bus subscriber. This means that the data connection interface is adapted to be connected to the data bus subscriber.Furthermore, the module unit according to the invention has a first switching means which is adapted to assume a first or a second switching state depending on a control input from the data bus participant, wherein in the first assumed switching state the first input interface is connected to the first output interface and in the second assumed switching state the first data connection interface is connected to the first output interface.Depending on the switching state of the switching device, either the first input interface is connected to the first output interface and data is only passed through the module unit, whereas in the other switching state, data present at the first input interface is not passed directly to the first output interface, but rather the data at the first output interface depends on the first data connection interface, for example, on the data that the data bus participant provides at this first data connection interface. For example, the switching device can be adapted to determine the respective switching states depending on whether a data bus participant is connected to the module unit or not.In the event that no data bus participant is connected to the module unit, the switching means can, for example, establish the first switching state, whereas in the event that a data bus participant is connected to the module unit, the switching means can establish the second switching state.

[0015] The modular unit according to the invention allows a data bus device to be removed from the local bus or a data bus device to be added without interrupting the local bus for an extended period of time. A particularly advantageous feature of the modular unit according to the invention is that the downstream data flow is not interrupted even when a data bus device is added or removed, because in this case, the modular unit still establishes a connection between the first input interface and the output interface.

[0016] In a preferred embodiment of the modular unit according to the invention, said unit has a second data connection interface which is connectable to the data bus subscriber - i.e. is adapted to be connected to the data bus subscriber -, wherein the first switching means is further adapted to connect the second data connection interface to the first input interface. This means that the data present at the first input interface are passed to a second data connection interface so that they can be passed to the data bus subscriber, which can then process them. The data bus subscriber can then output the processed data to the first data connection interface, which is connected to the first output interface, so that the processed data can be forwarded to the next modular unit or the next data bus subscriber.The switching means can establish the connection between the second data connection interface and the first input interface in the same switching state in which the first data connection interface is connected to the first output interface. However, it is also conceivable for the connection between the second data connection interface and the first input interface to be established in a switching state upstream or downstream of the first switching state. This means that the connection between the first data connection interface and the first output interface can be established at the same time as the connection between the second data connection interface and the first input interface, or the corresponding connections can be established one after the other. The data sent on the local bus can be transmitted in the form of data packets. The data packets can also be referred to as telegrams.For example, a data packet has a header, payload and, advantageously, a checksum.

[0017] In a further preferred embodiment of the module unit according to the invention, the first input interface is adapted to receive data, whereas the first output interface is adapted to send data. The first input interface receives data from an upstream data bus subscriber or an upstream module unit or the local bus master. The output interface sends data to a downstream data bus subscriber or a downstream module unit. Receiving and sending can be passive or active. This means that receiving can, for example, consist exclusively in a signal being present at the first input interface, but no signal processing taking place. In this case, it can be referred to as passive receiving. If, for example, signal processing takes place, it can be referred to as active receiving.The same applies to sending. If no signal processing is carried out, i.e. the signal is simply made available at the first output interface, this can be referred to as passive sending, whereas if signal processing is carried out, it can be referred to as active sending. The first input interface and the first output interface can both be passive or active, i.e. they can carry out no signal processing or some signal processing, or one of the two interfaces can be active while the other is passive, i.e. one carries out signal processing while the other does not. A person skilled in the art will be aware that the term signal processing can refer to any processing of a signal, for example coding, decoding, applying modulation or demodulation, converting to or from one transmission format to another format, etc.This also includes the corresponding signal processing for converting wired signals to wireless signals. In a ring bus, data is sent in the form of data packets that pass through all data bus nodes. Data packets are sent from the local bus master to the data bus nodes within a cycle frame.

[0018] A cycle frame can be defined, for example, as a recurring (cyclic), preferably equidistant, time interval in which data can be transmitted on the local bus. The cycle frame has, for example, at least one start identifier (SOC) and a time range for data transmission. Several start identifiers (SOC) of consecutive cycle frames are advantageously equidistant from one another. This time range is intended for the transmission of the data packets. The start identifier (SOC) and the data packets are transmitted via the local bus and pass through all data bus participants. The start identifier (SOC) can be transmitted separately, i.e., as an independent symbol, or advantageously contained in a start data packet (SOC packet).

[0019] Within the time range of the cycle frame, zero, one, or several data packets are transmitted. Advantageously, idle data is inserted into a cycle frame, in particular adjacent to at least one data packet. Advantageously, the transmission of the data packets and / or the idle data results in an uninterrupted signal on the local bus. This signal enables the data bus participants to synchronize their time with it. Advantageously, the cycle frame also has a trailer. The trailer has a variable length and follows the time range for data transmission, preferably up to the following start identifier (SOC) of the next cycle frame. Advantageously, the trailer contains idle data.

[0020] The data packets transmitted in the cycle frame are preferably originally generated by the local bus master and sent to the data bus devices via the ring bus. During generation, the local bus master can insert process data received from the controller, e.g. a PLC, into a data packet. However, the data packet can also contain process data from the local bus master itself and / or the controller. The data packet and thus the process data it contains then pass step by step through the individual data bus devices of the ring bus. The data packet can have a large number of symbols, with each symbol having a certain number of bits, for example 8 bits or 1 byte. The data packet accordingly passes through the data bus devices unit by unit, piece by piece, or in parts, e.g. in the form of symbols. The data bus devices therefore only have part of the data packet at any given time.When we talk about data here, this can also mean a symbol of the data packet that is currently passing through the ring bus. A data packet that carries process data can also be referred to as a process data packet. The process data packet contains the process data that is sent and / or received by the data bus participants on the local bus. Advantageously, the process data packet does not have an address for transmitting the process data to or from a data bus participant on the local bus. The process data is arranged in the process data packet in such a way that data bus participants can recognize the process data belonging to the respective data bus participant based on the respective position of the process data in the process data packet, for example one or more bits within an assigned contiguous data block (1 byte).Advantageously, the process data packet has an identifier (IDE) that is assigned to the type of data packet, i.e. the process data packet, and is identifiable by the data bus participant.

[0021] However, a data packet can also be a communication data packet that does not contain any process data and is used in particular for programming and / or controlling and / or monitoring and / or identifying at least one data bus participant. Advantageously, the communication data packet has an address assigned to at least one data bus participant. The data bus participant is preferably configured to evaluate the address and process the communication data packet accordingly.

[0022] In a further preferred embodiment of the module unit according to the invention, the first input interface has at least one detachable electrical contact for connection to the local bus and / or the first output interface has at least one detachable electrical contact for connection to the local bus. Signals from the upstream data bus participant or the upstream module unit can be received via the one electrical contact of the first input interface, and signals can be sent to the downstream data bus participant or the downstream module unit via the one electrical contact of the first output interface. Sending and receiving can be passive or active. Those skilled in the art will also be aware that the interfaces can also have a different number of contacts and that the number depends only on the specific design of the local bus.Those skilled in the art will also be aware that the contacts can be designed as plug-in, cutting, or other contacts that can establish an electrically conductive connection. It is also conceivable that an optical connection is established. The fact that the contacts are detachable means that they do not form a permanent connection, but can be separated again by applying a certain force.

[0023] The first data connection interface and / or the second data connection interface each have at least one detachable electrical contact for connection to the data bus participant. The second data connection interface can be adapted to send signals to the data bus participant via the contact, whereby this sending can occur passively or actively, and the first data connection interface can be adapted to receive signals from the data bus participant, whereby this receiving can occur passively or actively. The person skilled in the art is also aware that the interfaces can also have a different number of contacts and that the number depends only on the specific design of the data bus participants. The person skilled in the art is also aware that the contacts can be designed as plug-in, cutting or other contacts with which an electrically conductive connection can be established.It is also conceivable that an optical connection is established.

[0024] Each module unit has at least one connecting element for connecting to another module unit, wherein the first output interface of the module unit is electrically connected to a first input interface of the other module unit, or the first input interface of the module unit is electrically connected to a first output interface of the other module unit. The connecting element establishes a mechanical connection between the two module units, wherein the connection can only be released by applying a certain force. Accordingly, it can also be said that the connecting element is a mechanical connecting element.The mechanical connecting element is formed by the modular units having locking hooks on one side and recesses or undercuts on the opposite side. When two modular units are arranged next to one another, the locking hooks of one modular unit engage in the recesses or undercuts of the other modular unit, allowing them to be mechanically but detachably connected. When connecting the modular units, the connecting element is designed in such a way that an electrical connection of the interfaces is also established when the modular units are connected. The first output interface of one modular unit is electrically connected to the first input interface of the other downstream modular unit.The connecting element then ensures that the module units can only be separated from one another by applying a certain force that exceeds the holding force of the connecting element, thus breaking the electrical connections. The module units can also be adapted so that they can be arranged side by side on a DIN rail, and the connecting element can be designed to fix the module unit to the DIN rail, so that a further module unit can be attached directly to the module unit already fixed to the DIN rail with its connecting element. This allows several module units to be lined up and fixed to the DIN rail.In this case, the at least one contact of the first output interface of one module unit can be brought into contact with the first input interface of the downstream, directly adjacent module unit in order to establish an electrical connection.

[0025] In a further preferred embodiment of the modular unit according to the invention, it has at least one connecting element for connecting to a data bus subscriber, wherein the first data connection interface and / or the second data connection interface are electrically connected to the data bus subscriber. The connecting element can at least be designed in such a way that it allows a detachable mechanical connection of the data bus subscriber to the modular unit. For example, this can be achieved by suitable plug-in or clamp-type connecting elements on the modular unit and on the data bus subscriber, so that the data bus subscriber can only be detached from the modular unit when a holding force provided by these elements is applied. It is also conceivable to use securing elements to prevent accidental detachment of the data bus subscribers, for example in the event of strong vibrations.These locking elements can, for example, only be released with a tool or provide additional holding force. If the data bus device is connected to the module unit, the first and / or second data connection interface is also connected to the data bus device, which has corresponding complementary contacts. This can be achieved with appropriate plug-in or clamp-on contacts.

[0026] In a further preferred embodiment of the module unit according to the invention, it has a second input interface and a second output interface for connecting to the local bus. These interfaces form the uplink of the local bus and allow signals received by a downstream data bus subscriber or a downstream module unit at the second input interface to be sent to an upstream data bus subscriber or module unit via the second output interface. Sending and receiving can be passive or active. In a simple embodiment, the module unit can have a direct electrically or optically conductive connection between the second input interface and the second output interface. This means that in this embodiment, the data is only passed through the module unit in the uplink direction.Alternatively, the module unit can also have a third and a fourth data connection interface for connecting to the data bus subscriber, and a second switching means which is adapted to assume a first or a second switching state depending on the control input from the data bus subscriber, and to connect the second input interface to the second output interface in the first switching state and to connect the third data connection interface to the second input interface and / or to connect the fourth data connection interface to the second output interface in the second switching state. This means that in this embodiment, signals coming in the upstream direction from the downstream data bus subscriber or the downstream module unit can also be processed by the data bus subscriber.This has the advantage, particularly in a ring bus, that the symbols of the data packet passing through the data bus subscriber can be processed twice, namely once when they are sent in the downstream direction and the second time when they are sent in the upstream direction.

[0027] In a further preferred embodiment of the modular unit according to the invention, the first and / or second switching means are electrically controllable. This means that the control input is an electrical signal, and in accordance with the electrical signal, the first and / or second control means assume a corresponding switching state. The phrase "the first and / or second switching means" means that at least one of the switching means is configured in this way. If there is only a first switching means, it is configured in this way. If the modular unit has multiple switching means, at least one switching means is configured in this way, but preferably all switching means are configured in this way. Both switching means can be supplied with the same control signal, so that both switching means are controlled simultaneously, or the switching means can be supplied with different control signals.The control signal can, for example, be generated by the data bus device itself and only be generated when a specific condition is met. For example, both switching devices can initially be in the first switching state, thus providing the transmission of signals in both the downstream and upstream directions. When the data bus device is connected to the module unit, it can, for example, immediately provide a control signal, which causes the switching devices to switch to the second switching state, so that the signals are no longer bypassed by the data bus device but can be processed by it.However, it is also possible that the data bus participant initially needs a certain amount of time before it is ready for communication or processing, and a control signal is only sent to the module unit after this time, so that the data is only sent to the data bus participant when it is ready for communication or processing. The control signal itself can be any signal that is capable of transporting information from the data bus participant to the switching device. For example, this information can be transported using an electrical or optical signal. The control signal can, for example, be a binary signal that only indicates whether or not a switching state should be assumed. The first and / or the second switching device can be at least one electromechanical switch.For example, the first and / or second switching means can be a relay with an electromagnet, which is designed such that the electrical control signal can actuate the relay. The electromechanical switch can be located in or on the module unit. Alternatively, the first and / or second switching means can also be an electronic switch. The switch can be implemented in the form of a semiconductor component, such as a field-effect transistor, bipolar transistor, or a diode circuit. The electronic switch can be switched using the electrical control signal. Electronic switches advantageously have a shorter switching time than electromechanical switches and are also bounce-free and wear-free. The electronic switch can also be located in or on the module unit.

[0028] In a further preferred embodiment of the modular unit according to the invention, the first and / or second switching means are mechanically controllable. This means that the control input is a mechanical input and, in accordance with the input, the first and / or second control means assume a corresponding switching state. This means that the switching means are mechanically transferred from the first to the second switching state. For example, this can be done by a geometry arranged on the data bus participant which, when the data bus participant is arranged on the modular unit, switches the switching means or the switching means from a first switching state to a second switching state. If the data bus participant with the corresponding geometry is then removed again, the switching means or the switching means can be transferred back from the second switching state to the first switching state.For this purpose, the geometry can, for example, be designed in a pin-shaped manner in order to change the switching state in a correspondingly designed switching device.

[0029] In a further preferred embodiment of the modular unit according to the invention, the first and / or second switching means are optically controllable. This means that the control input is an optical signal, and depending on the signal, the first and / or second control means assume a corresponding switching state.

[0030] In a further preferred embodiment of the module unit according to the invention, the first switching means and / or the second switching means are adapted to assume the first switching state when no control input is present, in particular when no data bus participant is connected to the module unit. This means that when no data bus participant is connected to the module unit, no control signal is present or there is no geometry that causes a switching state. In this case, the first switching state is preferred, which allows the signals on the local bus to be passed through in the downward and upward directions. In this case, the module unit provides a pass-through. For example, this can be done by creating a low-impedance path or a conductive path between the input and output interfaces.

[0031] In a further preferred embodiment of the modular unit according to the invention, the first switching means and / or the second switching means are adapted in the first switching state to connect the second data connection interface and / or the third data connection interface to a fixed potential. This means that a reference potential is created.

[0032] In a further preferred embodiment of the modular unit according to the invention, it can have a housing made of plastic or another non-conductive material, so that the interfaces are electrically isolated from the environment. The housing can, for example, be adapted to support the data bus device. Furthermore, the housing can be adapted to fix the modular unit to a top-hat rail.

[0033] In a further preferred embodiment of the modular unit according to the invention, the modular unit has a voltage connection interface for connecting a voltage source to the data bus device. The voltage connection interface can be designed similarly to the data connection interfaces, allowing a detachable connection of the data bus device to the modular unit. The voltage connection interface supplies the data bus device with mains voltage, allowing the data bus device to be operated. The associated voltage source can be located in or on the modular unit, or can be arranged outside the modular unit.

[0034] In yet another preferred embodiment of the modular unit according to the invention, the modular unit has a control input interface for receiving the control input from the data bus participant. The control input interface can also be configured similarly to the data connection interfaces and the voltage connection interface, so that it enables a detachable connection of the data bus participant to the modular unit. 4. Brief description of the drawings

[0035] The invention is explained in more detail below using exemplary embodiments and the accompanying drawings. Further details, features, and advantages of the subject matter of the invention will become apparent from the described exemplary embodiments. They show: Fig. 1 shows a schematic block diagram of an exemplary automation system with a programmable logic controller, a higher-level bus, an exemplary embodiment of the modular unit according to the invention, and an exemplary ring bus; Fig. 2 shows a schematic circuit diagram of an exemplary embodiment of the modular unit according to the invention without a data bus participant arranged thereon, with the switching means in the first switching state; and Fig. 3 shows a schematic circuit diagram of an exemplary embodiment of the modular unit according to the invention with a data bus participant arranged thereon, with the switching means in the second switching state. 5. Description of preferred embodiments

[0036] Figure 1shows a schematic block diagram of an automation system. It will be understood by those skilled in the art that the automation system shown is only an example, and all elements, modules, components, participants, and units belonging to the automation system may be designed differently but can nevertheless fulfill the basic functionalities described here.

[0037] The Figure 1The automation system shown has a higher-level controller 1, which can be implemented, for example, with a programmable logic controller (PLC). Such a PLC 1 is basically used to control and regulate the process carried out by the automation system. Nowadays, however, PLCs 1 in automation systems also perform more advanced functions, such as visualization, alarm generation, and recording of all process-related data, and as such, the PLC 1 functions as a human-machine interface. PLC 1s are available in different performance classes, each with different resources (computing capacity, memory capacity, number and type of inputs and outputs, and interfaces), which enable the PLC 1 to control and regulate the process of the automation system. A PLC 1 usually has a modular design and consists of individual components, each of which performs a different task.Typically, a PLC 1 consists of a central processing unit (with one or more main processors and memory modules) and several modules with inputs and outputs. Such modular PLC 1s can be easily expanded by adding modules. The modules that must be integrated into the PLC 1 depend on the complexity of the process and the complexity of the automation system's design. In today's automation systems, the PLC 1 is usually no longer an independent system; instead, the PLC 1 is connected to the internet or intranet via appropriate interfaces (not shown here). This means that the PLC 1 is part of a network through or from which the PLC 1 can receive information, instructions, programming, etc.For example, PLC 1 can receive information about the materials fed into the process via a connection to a computer on the intranet or internet, so that the process can be optimally controlled, for example based on knowledge of their quantity or nature. It is also conceivable for PLC 1 to be controlled by a user via the intranet or internet. For example, a user can access PLC 1 with the help of a computer, also called a master computer, and check, change, or correct its user programming. Accordingly, access to PLC 1 is possible from one or more remote control rooms or control centers. The master computers can, if necessary, have visualization devices for displaying process sequences.

[0038] To control the process of the automation system, the PLC 1 is connected to automation devices. To keep the wiring effort to a minimum, bus systems are used for these connections. Figure 1 In the embodiment shown, the PLC 1 is connected to a local bus master 3 of a subordinate local bus system via a higher-level bus 2, which in the embodiment shown here can be a fieldbus. However, not only a local bus master 3 of a local bus can be connected to the higher-level bus 2, as in the embodiment shown here, but also any other devices (not shown here) that are designed to communicate with the PLC 1.

[0039] In the embodiment shown here, the higher-level bus 2 is connected to the local bus master 3. For this purpose, the local bus master 3 has a first interface 4 which is designed such that it can be connected to the higher-level bus 2. For this purpose, the interface 4 can, for example, have a receptacle in the form of a socket, and the higher-level bus 2 can have a plug that can be received in the socket. The plug and the socket can, for example, be a modular plug and a modular socket, i.e. each wire of the higher-level bus 2 is electrically or optically connected to a connection in the modular socket. However, those skilled in the art will also be aware of other possibilities for designing an interface 4 so that the local bus master 3 can be electrically or optically connected to the higher-level bus 2.Those skilled in the art are familiar with screw, twist, click, or plug-in connections that can be used to establish an electrical or optical connection. In these cases, a male connector is usually received by a female counterpart. This connector not only establishes the electrical or optical connection but also ensures that the two parts are mechanically coupled and can only be separated again with the application of a certain force. However, it is also conceivable that the higher-level bus 2 is hard-wired to the interface 4.

[0040] The local bus master 3 in the embodiment shown here has a further second interface for connecting the local bus master 3 to the local bus. The local bus is configured as a ring bus 6. In this case, the second interface is divided into a first part 5a and a second part 5b. The first part 5a of the second interface establishes the downlink in the ring bus 6, and the second part 5b of the second interface establishes the uplink in the ring bus 6.

[0041] The ring bus 6, whose data transmission direction is indicated by arrows in the Figure 1 shown embodiment, has in the embodiment shown here several module units 8a, 8b, ..., 8n for connection to data bus participants 20a, 20b, ..., 20n.

[0042] A data packet sent from the local bus master 3 to the local bus 6 passes through all module units 8a, 8b, ..., 8n and the data bus nodes 20a, 20b, ..., 2n connected to them. A data bus node 20a, 20b, ..., 20n always receives only a portion of the data packet from its upstream data bus node 20a, 20b, ..., 20n or a module unit 8a, 8b, ..., 8n. After a period of time in which the data contained in this portion can be processed by the data bus node 20a, 20b, ..., 20n, the portion is forwarded to the downstream data bus node 20a, 20b, ..., 20n, and simultaneously, a new portion of the data packet is received by the upstream data bus node 20a, 20b, ..., 20n or module unit 8a, 8b, ..., 8n. In this way, all portions of the data packet pass sequentially through all data bus nodes 20a, 20b, ..., 20n or module units 8a, 8b, ..., 8n.The local bus is advantageously designed in a ring-shaped structure. Such local buses can also be referred to as a ring bus 6. The local bus can alternatively be designed in a strand-shaped or star-shaped configuration, or in a combination or hybrid form of the aforementioned. The module units 8a, 8b, ..., 8n can also be referred to as the basic elements of the ring bus 6. The ring bus infrastructure is constructed by the module units 8a, 8b, ..., 8n, and the data bus devices 20a, 20b, ..., 20n are interchangeable, so that the ring bus 6 can be configured with any desired data bus devices 20a, 20b, ..., 20n. With the help of the module units 8a, 8b, ..., 8n it is also ensured that even if a data bus participant 20a, 20b, ..., 20n is removed, the communication between the remaining data bus participants 20a, 20b, ..., 20n is not interrupted because the communication takes place via the still existing module units 8a, 8b, ..., 8n.

[0043] In the exemplary embodiment shown here, the module units 8a, 8b, ..., 8n each have a first input interface 9 for receiving data from an upstream or preceding participant on the ring bus 6, for example an upstream module unit, a data bus participant, or a local bus master 3. Reception can be active or passive, i.e., signal processing can or can not take place. In the case of the module unit 8a shown, it receives data from the upstream local bus master 3 via the first input interface 9. Furthermore, the module units 8a, 8b, ..., 8n in the exemplary embodiment shown here each have a first output interface 10 for forwarding data to a downstream or subsequent module unit and / or data bus participant.In the case of module unit 8a, this sends data to the downstream module unit 8b with the attached data bus subscriber 20b via the first output interface 10. Sending can be active or passive, i.e., signal processing can take place or not. The first input interface 9 and the first output interface 10 serve to propagate data in the downstream direction of the ring bus 6, i.e., away from the local bus master 3. Furthermore, the module units 8a, 8b, ..., 8n also have a second input interface 11 and a second output interface 12, which serve to propagate data in the upstream direction of the ring bus 6, i.e., toward the local bus master 3.In the case of module unit 8a, the second input interface 11 is designed to receive data from the downstream or subsequent module unit 8b, with or without the data bus subscriber 20b arranged thereon, and the second output interface 12 is designed to forward data to the upstream or preceding module unit and / or data bus subscriber, here the local bus master 3. It can thus be said that the output interfaces 10 and 12 are transmitter interfaces, whereas the input interfaces 9 and 11 are receiver interfaces.

[0044] Even though the local bus master 3 and the individual module units 8a, 8b, ..., 8n, with or without attached data bus participants 20a, 20b, ..., 20n, are shown spaced apart from one another in the exemplary embodiment shown here, the local bus master 3 can also be arranged decentrally from the module units 8a, 8b, ..., 8n. As those skilled in the art will know, the module units 8a, 8b, ..., 8n and the local bus master 3—which also represents a data bus participant of the ring bus 6—can also be connected directly to one another. The contacts of one module unit 8a, 8b, ..., 8n engage in corresponding receptacles or receiving contacts of a directly adjacent module unit 8a, 8b, ..., 8n, thus establishing an electrical or optical connection between the module units 8a, 8b, ..., 8n so that data can be sent in the downlink and uplink directions. For example, the module units 8a, 8b, ..., 8n have receptacles on the side facing away from the master and contacts on the side facing the master. If the module units 8a, 8b, ..., 8n are then arranged in a row accordingly, the contacts of one module unit 8a, 8b, ..., 8n each engage in the receptacles of the other module unit 8a, 8b, ..., 8n and an electrical or optical connection can be created. The local bus master 3 then has corresponding contacts on the side which engage in the receptacles of the first module unit 8a in order to create an electrical or optical connection between the interfaces 5a and 9 or the interfaces 5b and 12. However, those skilled in the art will also be aware of other possibilities, e.g. pressure contacts, knife and fork contacts, for how two module units 8a, 8b, ..., 8n arranged directly next to one another can establish an electrical or optical connection. The contacts shown in . Figure 1separately shown module units 8a, 8b, ..., 8n are arranged in a common housing, so that their respective first and second input and output interfaces 9 to 11 are permanently interconnected within the housing, for example by means of conductor tracks.

[0045] It is intended that the module units 8a, 8b, ..., 8n and the local bus master 3 are directly connected to one another. These also have corresponding mechanical mounts or mechanical connecting elements with which the individual module units 8a, 8b, ..., 8n and the local bus master 3 can be connected to one another. In this case, a module unit 8a, 8b, ..., 8n has a projection in the form of a locking hook on one side and an undercut on the other side. If the module units 8a, 8b, ..., 8n are then lined up next to one another, a projection engages with an undercut of the other module unit 8a, 8b, ..., 8n, thus creating a mechanical coupling. For easy arranging of the module units 8a, 8b, ..., 8n, they can also be arranged on a common mount, for example a top-hat rail. The module units 8a, 8b, ..., 8n can be provided with appropriate fastening means for fastening on the DIN rail.Alternatively or additionally, the module units 8a, 8b, ..., 8n can also have, for example, detachably connectable fastening means with which the module units 8a, 8b, ..., 8n can be attached either to the top-hat rail or to another mounting. For this purpose, the detachably connectable fastening means can be interchangeable, and a corresponding fastening means for the desired mounting can be connected to the module units 8a, 8b, ..., 8n so that they can be attached to the desired mounting.

[0046] The data bus participants 20a, 20b, 20n that can be attached or plugged onto the module units 8a, 8b, ..., 8n, connect via data connection interfaces 13a, 14a, 15a, 16a to corresponding data connection interfaces 13b, 14b, 15b, 16b on the module units 8a, 8b, ..., 8n.

[0047] The data connection interfaces 13b, 14b, 15b, 16b on the module units 8a, 8b, ..., 8n are in turn connected to the first and second input and output interfaces 9, 10, 11, 12. The data bus participants 20a, 20b, 20n have, for example, an arithmetic-logic unit or another type of processing core with the aid of which data can be processed. This processing unit can be a processor, a microcontroller, or a computing circuit, which can in particular be formed from gate elements of an integrated circuit. The computing circuit can be designed as digital logic, which in particular is designed as at least part of a semiconductor chip. The circuits can be implemented in an application-specific integrated circuit (English) ASIC) or in a field programmable (logic) gate arrangement (English)FPGA). The data bus participants 20a, 20b, 20n can be designed to process data received from the ring bus 6 and to output data. The data to be processed can be received either from an upstream data bus participant 20a, 20b, 20n, the local bus master 3, or from participant inputs 21 of the data bus participant 20a, 20b, 20n. The participant inputs 21 of the data bus participant 20b can be connected to sensors that send, for example, measurement data, status data, etc. Processed data can be output either to a downstream data bus participant 20n or to the participant outputs 22 of the data bus participant 20b. The participant outputs 22 of the data bus participant 20b can be connected to actuators that, for example, perform a specific action with the help of the data addressed to them.

[0048] The data bus devices 20a, 20b, 20n shown in this embodiment are also often referred to as I / O modules due to their inputs and outputs 21, 22, which can be connected to sensors or actuators. Although the data bus devices 20a, 20b, 20n are depicted as spatially separated from the sensors or actuators in the embodiment shown here, the sensors or actuators can also be integrated into the data bus devices 20a, 20b, 20n.

[0049] The different interfaces 9 to 19 on the module units 8a, 8b 8n, which are used in connection with Figure 2can, for example, have a receptacle in the form of a socket, and the respective connecting elements, such as the connecting lines 7 of the ring bus 6, can each have a plug that can be received by the socket. However, those skilled in the art will also be aware of other possibilities as to how the interfaces 9 to 19 can be designed so that the respective connecting elements can be connected electrically or optically to the interfaces 9 to 19. Those skilled in the art will be aware of screw, twist, click, or plug-in connections, with the aid of which an electrical or optical connection can be established. In this case, a male plug is usually received by a female counterpart.This receptacle usually not only establishes the electrical or optical connection, but also ensures that the two parts are mechanically connected and can only be separated again with the application of a certain force. Furthermore, those skilled in the art will know that not all interfaces 9 to 19 need to be of the same type. For example, some of the interfaces 9 to 19 may be designed as plug connections, while others may be designed as screw connections.

[0050] The different interfaces 9 to 19 on the module units 8a, 8b, 8n, as in Figure 1shown as an example for the module unit 8a, can be arranged in any position and in any order on the housing of the module unit 8a. Further interfaces, not shown here, can also be attached to the module units 8a, 8b, 8n, by means of which further data can be exchanged between the module units 8a, 8b, 8n and the data bus participants 20b, 20n arranged thereon. Furthermore, further interfaces can also be attached to the module units 8a, 8b, 8n in order to exchange data between the module units 8a, 8b, 8n, such as, for example, a status signal looped through all module units 8a, 8b, 8n.

[0051] In the Figure 2 An embodiment of a module unit without a data bus subscriber arranged thereon is shown with the switching means 23, 24 in the first switching state. Figure 2 The module unit 8a shown is the one in Figure 1 shown module unit 8a. The Figure 2 However, the module unit 8a shown can also be any of the other module units 8a, 8b, ..., 8n from Figure 1 As in Figure 1As shown, the module unit 8a is connected to the local bus master 3 via the first input interface 9 and to the module unit 8b via the first output interface 10. This direction forms the downward direction for the data in the ring bus 6, i.e., the direction away from the local bus master 3. The second input interface 11 of the module unit 8a is connected to the module unit 8b, and the second output interface 12 is connected to the local bus master 3. This direction forms the upward direction for data in the ring bus 6, i.e., in the direction toward the local bus master 3. The data in the downward and upward directions are routed in the ring bus 6 from a participant - a participant can be a module unit 8a, 8b, ... 8n with or without a data bus participant 20a, 20b, ..., 20n arranged thereon, or just a data bus participant 20a, 20b, ..., 20n - to an upstream or downstream participant. As already mentioned with regard to Figure 1As described above, in order to ensure that the ring bus 6 is not interrupted, the data must be able to be passed from one participant to another. To ensure the functionality of the ring bus 6, the data must be looped through the module units 8a, 8b, ..., 8n in the uplink and downlink directions, or forwarded without interruption, even if, for example, no data bus participant 20a is mounted on the module unit 8a. For this purpose, the module unit 8a has a first switching means 23 for the downlink direction and a second optional switching means 24 for the uplink direction. As shown in Figure 2 As shown, the first switching means 23 switches the downward direction and the second switching means 24 switches the upward direction. The first switching means 23 switches the downward direction in such a way that in the Figure 2In the first switching state shown, the first input interface 9 of the module unit 8a is electrically or optically connected to the first output interface 10. The data originating from the local bus master 3 are accordingly passed directly in the downward direction through the module unit 8a to the module unit 8b. The second switching means 24, optionally shown here, switches the upward direction such that in the Figure 2 In the first switching state shown, the second input interface 11 of the module unit 8a is electrically connected to the second output interface 12. The data coming from the module unit 8b is accordingly forwarded directly to the local bus master 3. As an alternative to the second switching means 24, a direct connection can also be present between the second input interface 11 and the second output interface 12.

[0052] In the embodiment shown here, the first and second switching means 23, 24 are either electronic switches or electromechanical switches. Those skilled in the art will appreciate that the respective switching means 23, 24 can be constructed from one or more electronic switches or electromechanical switches. For example, the respective switching means 23, 24 can be constructed from a relay with multiple relay contacts, such as multiple normally closed and normally closed contacts. The switching means 23, 24 can consist of either semiconductor elements or relays and can be controlled by the control input in the form of an electrical control signal.However, it is also known to the person skilled in the art that the first and second switching means 23, 24 can also be mechanical switches - not shown here - which can switch between the first and the second switching state depending on a mechanical control input, such as a pin-shaped geometry attached to the data bus participant 20a.

[0053] As in Figure 2 As shown, the module unit 8a has a control input interface 19b for receiving the control input, for example a control signal, from a data bus user 20a and / or for forwarding the control input to the switching means 23, 24. In the Figure 2In the example shown, the control input controls all the switching devices 23, 24 shown simultaneously. This means that all switches in the switching devices 23, 24 switch simultaneously depending on the control input, so that the switching devices 23, 24 each assume either the defined first switching state or the defined second switching state depending on the control input. However, the switching devices 23, 24 can also be switched sequentially. In the example shown in Figure 2In the embodiment shown, the switching means 23, 24 are in the first switching state. The switching means 23, 24 can assume this first switching state, for example, when there is no control input, for example when no data bus participant 20a is connected to the module unit 8a. As already described above, the ring bus 6 is not interrupted if a data bus participant 20a is missing, or if there is no control input from the data bus participant 20a. This means that in the event of a fault in the data bus participant 20a, for example, the first switching state can be assumed because a corresponding control input is missing. This fault case can be that the data bus participant 20a is no longer able to process the signals, or the data bus participant 20a no longer provides correct outputs, or has mechanically detached itself at least partially from the module unit 8a, so that not all contacts are still present.

[0054] The switching means 23, 24 can be integrated in the module unit 8a or located outside the module unit 8a. Furthermore, Figure 2 that at least one data connection interface 13b, 15b per switching means 23, 24 is connected to ground in the first switching state. This enables a defined zero signal to be present at least at the two data connection interfaces 13b, 15b in the first switching state. However, it is known to the person skilled in the art that the switching means 23, 24 also function according to the invention without grounding the data connection interfaces 13b, 15b in the first switching state. The data connection interfaces 14b and 16b are in the Figure 2 shown embodiment is not wired.

[0055] Figure 2also shows that the module unit 8a further comprises a voltage connection interface 17b, 18b for connecting a voltage source to the data bus device 20a. The voltage connection interface 17b, 18b can be designed similarly to the other interfaces on the module unit 8a, so that a detachable connection of the data bus device 20a to the module unit 8a is possible. If a data bus device 20a is arranged on the module unit 8a, the voltage connection interface 17a, 18a can supply the data bus device 20a with mains voltage so that the data bus device 20a can be operated. It is known to those skilled in the art that the respective voltage source can be located in the module unit 8a or can be arranged outside the module unit 8a.

[0056] Figure 3shows a schematic circuit diagram of an embodiment of a module unit 8b with a data bus subscriber 20b attached thereto with the switching means 23, 24 in the second switching state. Figure 3 The module unit 8b shown is the one already shown in Figure 1 shown module unit 8b with a data bus participant 20b arranged thereon. However, the shown module unit 8b can also be the module already shown in Figure 2 shown module unit 8a with a data bus participant 20a attached to it, or for example the one shown in Figure 1 shown module unit 8n.

[0057] As already mentioned regarding Figure 1 As described above, the different interfaces 9 to 19 on the module unit 8b can be designed differently. Figure 3In the embodiment shown, the interfaces 13b to 19b, which connect the data bus participant 20b to the module unit 8b, can be designed as plug-in connections, so that the data bus participant 20b can be easily plugged onto the module unit 8b by hand without the use of tools. For this purpose, the data bus participant 20b can have interfaces that correspond to the interfaces 13b to 19b of the module unit 8b and that can be connected to the interfaces 13b to 19b.

[0058] The advantage of the module unit 8b is that the data bus participant 20b can be arranged on the module unit 8b during ongoing operation of the bus. As already described above, this can be done by plugging the data bus participant 20b onto the module unit 8b. After all interfaces 13b to 19b are connected and the data bus participant 20b is supplied with voltage, for example via the voltage connection interface 17b, 18b, the data bus participant 20b can immediately transmit a control input in the form of an electrical signal to the module unit 8b via the control input interface 19b so that the switching means 23, 24 switch from the first switching state to the second switching state. However, the data bus participant 20b can also transmit the control input at a later time via the control input interface 19b. For example, after it has been initialized, or an input of the data bus participant 20b, as with respect to Figure 1 described, wired, etc.

[0059] In the Figure 3 In the embodiment shown, the control input in the form of an electrical signal is present at the control input interface 19b as long as the data bus participant 20b is connected to the module unit 8b. Alternatively, a suitable electronic circuit can also be used, which enables the switches 23, 24 to switch back and forth between the first and second switching states in response to short switching pulses emanating from the module unit 18b.

[0060] In the Figure 3In the second switching state shown, the first data connection interface 13b is connected to the first input interface 9 and the second data connection interface 14b is connected to the first output interface 10, the third data connection interface 15b is connected to the second input interface 11 and the fourth data connection interface 16b is connected to the second output interface 12. A direct connection in the module unit 8b between the respective input and output interfaces takes place in the second switching state, as in Figure 3shown, does not take place. Instead, the uplink and downlink of the ring bus 6 is looped through the data connection interfaces 13b to 16b by the data bus participant 20b. The data bus participant 20b can process the looped data in the uplink and / or downlink directions before forwarding it to the corresponding output interface 10 or 12.

[0061] In the last module unit 8n arranged in the ring bus 6, the second switching means 24 can also Figure 3 Use the switching state shown to loop data coming from the downstream direction through the data bus device 20n and then send it back to the upstream direction. In this case, no bridge unit is required on the last module unit 8n, which would otherwise connect the first output interface 10 to the second input interface 11.

[0062] The module unit 8b also allows the data bus device 20b to be removed during operation. After the data bus device 20b has been removed from the module unit 8b and the connection of the data bus device 20b has been disconnected from the control input interface 19b, the control input is also removed, or the control signal is set to zero. This results in the switching means 23, 24 returning to the first switching state, as shown in Figure 2 is shown and a transmission takes place in both downward and upward directions. List of reference symbols

[0063] 1 Programmable logic controller (PLC) 2 Higher-level bus 3 Local bus master 4 First interface 5a, b Second interface 6 Ring bus 7 Connecting lines 8a, b, n Module units 9 First input interface 10 First output interface 11 Second input interface 12 Second output interface 13a, b Second data connection interface 14a, b First data connection interface 15a, b Third data connection interface 16a, b Fourth data connection interface 17a, b, 18a, b Voltage connection interface 19a, b Control input interface 20a, b, n Data bus participants 21 Participant input 22 Participant output 23 First switching device 24 Second switching device

Claims

1. A system for connecting a data bus subscriber (20a, 20b, ..., 20n) to a local ring bus (6, 7), the system comprising: a plurality of module units (8a, 8b, 8n), each of the module units (8a, 8b, 8n) comprising: an upstream connection (6) with the local ring bus (6, 7), a downstream connection (7) with the local ring bus (6, 7), wherein the upstream connection (6) and the downstream connection (7) form the local ring bus (6, 7) which interconnects the module units (8a, 8b, 8n); an internal switch (23, 24); and a plurality of first data connection interfaces (13b, 14b, 15b, 16b); and a plurality of data bus subscribers (20a, 20b, ..., 20n), each of the data bus subscribers (20a, 20b, ..., 20n) comprising: an interface (21, 22) connected to sensors or actuators; and a plurality of second data connection interfaces (13a, 14a, 15a, 16a), wherein each of the first data connection interfaces (13b, 14b, 15b, 16b) is correspondingly connected to each of the second data connection interfaces (13a, 14a, 15a, 16a) via a releasable mechanical coupling, the system being characterized in that the module units (8a, 8b, 8n) comprise a mechanical connection element comprising latching hooks that engage recesses or undercuts of an adjacent module unit (8a, 8b, 8n).

2. The system according to claim 1, wherein each of the data bus subscribers (20a, 20b, ..., 20n) communicates by transmitting data via the first data connection interfaces (13b, 14b, 15b, 16b) and the second data connection interfaces (13a, 14a, 15a, 16a) and via the upstream connection (6) and the downstream connection (7) between each of the module units (8a, 8b, 8n) corresponding to the data bus subscribers (20a, 20b, ..., 20n).

3. The system according to claim 2, wherein the internal switch (23, 24) in each of the module units (8a, 8b, 8n) controls connections between the data bus subscribers (20a, 20b, ..., 20n) and the local ring bus (6, 7).

4. The system according to claim 1, wherein the data bus subscribers (20a, 20b, ..., 20n) convert control signals or measurement signals into process data for the local ring bus (6, 7).

5. The system according to claim 1, wherein the local ring bus (6, 7) is configured to transmit an uninterrupted signal, preferably wherein the data bus subscribers (20a, 20b, ..., 20n) are configured to synchronize based on the uninterrupted signal.

6. The system according to claim 1, wherein one or more of the data bus subscribers (20a, 20b, ..., 20n) process data packets transmitted on the upstream connection (6) and the downstream connection (7).

7. The system according to claim 1, wherein one or more of the module units (8a, 8b, 8n) are configured to pass signals along the local ring bus (6, 7) without a connected data bus subscriber (20a, 20b, ..., 20n) or without a control signal of the data bus subscriber (20a, 20b, ..., 20n).

8. The system according to claim 1, wherein one or more of the data bus subscribers (20a, 20b, ..., 20n) is powered by a corresponding module unit (8a, 8b, 8n) of the module units (8a, 8b, 8n).

9. The system according to claim 1, wherein the module units (8a, 8b, 8n) are arranged in a common housing.

10. The system according to claim 1, wherein the module units (8a, 8b, 8n) monitor a control input from a corresponding data bus subscriber (20a, 20b, ..., 20n) of the data bus subscribers (20a, 20b, ..., 20n) for an electrical signal that indicates that the corresponding data bus subscriber (20a, 20b, ..., 20n) is connected.

11. The system according to claim 1, further comprising a local bus master (3) connected to the data bus subscribers (20a, 20b, ..., 20n) and the module units (8a, 8b, 8n).

12. The system according to claim 11, wherein the local bus master (3) defines a cycle frame of the local ring bus (6, 7) by transmitting a data start identifier, SOC, the data start identifier being an independent symbol.

13. The system according to claim 11, wherein the local bus master (3) transmits idle data to ensure an uninterrupted signal to the local ring bus (6, 7), and wherein the data bus subscribers (20a, 20b, ..., 20n) are configured to synchronize based on the uninterrupted signal.