DE202012100754U1 - Universal control unit with BUS and WEB connection - Google Patents

Abstract

Universal control unit (UCU) with at least one interface for connection to another UCU and / or to a BUS line and / or to a control terminal

Description

The invention relates to a universal control unit (Universal Control Unit UCU) according to the preamble of patent claim 1.

It is known to form bus systems with a bus line and a plurality of bus devices connected thereto. The bus is used for data transmission and replaces parallel wiring of the individual bus devices with a single bus line, which connects the bus devices in serial cabling. Both digital and analog data and / or control signals can be transmitted via the bus.

It is also known to connect bus systems at a central location with a power supply that feeds power to supply the individual bus users in the bus. Such a bus supply is usually a DC voltage supply, which converts the usual mains voltage of 230 V, 50 H into a DC voltage depending on the bus type between 5 V and 30 V. The output of the DC power supply is connected directly to the bus line.

To couple the individual bus devices to the bus line, also referred to below as the fieldbus, a bus coupler is used to process digital input and output signals. The task of a bus coupler is to bundle a multiplicity of different signals and forward them via a uniform bus signal to a central controller controlling the bus system or to pass on commands from this central control unit to the bus devices connected to the bus coupler. Bus couplers can be designed with their own intelligence and so decentralized, so small control tasks. without intervention of the central control unit, hereinafter referred to as master, take over. A Bus Coupler thus represents a Busanschalteinheit, which is equipped with an interface to a fieldbus.

Such bus systems are used, inter alia, in building automation. The bus subscribers connected to the fieldbus can in this case be formed by sensors, actuators or operating units. For example, can be used as sensors temperature or light sensors, as actuators, for example, motors for blinds or blinds, actuators for heating valves or decentralized pumps for radiators and operating units as switches, dimmers, buttons, room thermostats or complex room control units. Each assigned to a room bus subscribers are connected according to the prior art directly to the fieldbus via a bus coupler. The bus coupler contains a decoupling unit in the manner of a filter, with which the power supply transmitted via the fieldbus is disconnected from the data transmission.

It is not uncommon for the line to be damaged by a bus user as a result of subsequent installation work within a room. For example, by attaching mounting means for a picture to be suspended, the bus line may be damaged so as to cause a short circuit in the line supplying the bus user. This fault has the consequence that the entire bus system is impaired in its function or even completely collapses. In the worst case, an irreversible damage of the bus voltage supply and / or other bus subscribers may take place, so that the entire bus system fails completely and individual devices or device components must be replaced.

Furthermore, in automation technology, in particular in process automation technology, field devices are used which serve to determine and monitor process variables. As a rule, field devices in modern automation systems are connected via communication networks such as HART multidrop, point-to-point connection, Profibus or Foundation Fieldbus to a superordinated unit, which is referred to as a control system or control room. This higher-level unit is used for process monitoring and commissioning and for operating the field devices. Additional components necessary for the operation of fieldbus systems, which are directly connected to a fieldbus and which in particular serve for communication with the higher-level units, are often referred to as field devices. These additional components are e.g. to remote I / Os, to gateways, to linking devices or to controllers.

The share of software in field devices is rising steadily. The advantage of using microcontroller-controlled field devices is that application-specific software programs can be used to implement a multiplicity of different functionalities in a field device. Also, program changes are relatively easy to perform. On the other hand, the high flexibility of the program-controlled field devices is offset by a relatively low processing speed and thus a correspondingly low measuring rate as a result of the sequential program execution.

In order to increase the processing speed, ASICs - Application Specific Integrated Circuits - are used in the field devices whenever it makes sense. Due to the application-specific configuration, these blocks can process data and signals much faster than a software program can do that. ASICs are particularly suitable for compute-intensive applications.

A disadvantage of the application of ASICs is that the functionality of these blocks is fixed. A subsequent change in functionality is not readily possible with these blocks. Furthermore, the use of ASICs pays off only in relatively large quantities, since the development effort and the associated costs are high.

To circumvent the malady of the fixed functionality is out of the WO 03/098154 a configurable field device is known in which a reconfigurable logic device is provided in the form of an FPGA. In this known solution, the logic module with at least one microcontroller, which is also referred to as an embedded controller, configured at system start. After the configuration is completed, the required software is loaded into the microcontroller. The reconfigurable logic device required for this must have sufficient resources, namely logic, wiring and memory resources, to fulfill the desired functionalities. Logic modules with many resources require a lot of energy, which in turn makes their use in process automation unrestricted from a functional point of view. A disadvantage in the use of logic devices with few resources and thus with low energy consumption is the significant limitation in the functionality of the corresponding field device.

WO 96/12993 describes a device for accessing field devices in a distributed control system with a redundant wireless access to field devices.

DE 10 2007 003 196 A1 discloses a communication system for exchanging data in an automation system for communication between central and peripheral devices.

In the communication path between the central and peripheral devices is connected a converter for wired communication with the central device and for wireless communication with the peripheral devices. Such a converter may e.g. a fieldbus coupler or a repeater.

The invention has for its object to provide a BUS and WEB-capable UCU (Universal Control Unit) available that can be used both as a central unit and as a fieldbus node for various devices, in particular for defined applications of building automation.

The design and construction of the UCU should be designed on the hardware side so that they can be used both as stand-alone devices and for networked devices by simply plugging them onto a function-related motherboard. As a result, depending on the product or product group, only the development of the motherboard with appropriate signal conditioning and peripheral connections to the UCU and the "application firmware" to be developed individually are necessary. This firmware is also to be integrated into the UCU and thus enables the use of the UCU as the central unit for the handling of the control and control processes intended for the product. As a further firmware package, the functionality of the web server is to be implemented, which enables communication with human-machine interfaces (PC, HMI, etc.) for remote monitoring and service via network services across product or groups.

The solution of the problem arises from the features of claim 1. Advantageous developments are the subject of the dependent claims.

• 1. Eine hoch integrierte Mikro-Controller-Unit, welche beim Einsatz der UCU als Feldbusknoten eine Verarbeitung, Verifizierung und Koordination der Bus-Daten sowie die Weitergabe an ein SUB-Bussystem zur Peripherie-Steuerung in Echtzeit erlaubt. Bei der Verwendung der UCU als Stand-Alone-Zentraleinheit können darüber Funktionsports für digitale, analoge und zeitdiskret-modulierte Signale zur nativen Steuerung der darauf aufgesetzten Applikation bereitgestellt werden;
• 2. Zwei voneinander unabhängige Bus-Schnittstellen, welche zusammen mit der vorhergehend genannten Mikro-Controller-Unit als Innovation die Implementierung eines aktiven Bus-Repeaters zur intelligenten Verwaltung der daran angeschlossenen und registrierten Feldbusknoten durch die Funktion der gezielten Weiterleitung von Bus-Daten an die UCU-Einheiten, gleich der Funktion eines Switches in anderen Netzwerkarten, gestattet;
• 3. Galvanische Trennung der Steuerkomponenten gegenüber Bus-Schnittstellen sowie zwischen den Bus-Schnittstellen. Weiter soll der Schutz gegen ESD und differenzielle Transienten sichergestellt sein, um eine höchstmögliche Betriebssicherheit zu gewährleisten;
• 4. Feldbus, welcher nach der weit verbreiteten EIA-485-Norm ausgeführt werden kann, um eine hohe Toleranz gegenüber elektromagnetischen Störungen, kostenminimierte Busverdrahtung durch Standard-Steuerleitungen sowie schnelle Datenübertragungsraten über große Entfernungen (> 1 km) zu gewährleisten. Als Kommunikationsprotokoll findet das Modbus-Protokoll im RTU-Modus nach genormter Spezifikation Verwendung. Aufgrund der Tatsache, dass der „Modbus“ den De-facto-Standard in der Industrie- und Gebäudeautomation darstellt, wird eine hohe Kompatibilität mit den meisten in diesem Bereich tätigen Herstellern von Komponenten und Geräten gewährleistet. Das Modbus-Protokoll soll mit einem Datentransport-Protokoll überlagert werden können, welches die Nutzung der innovativen integrierten Repeater/Switch-Funktion erst ermöglicht, ohne dabei die beschriebene Kompatibilität zu beeinträchtigen.
• 5. Für den Einsatz der UCU als Stand-Alone-Gerät werden genügend Speicher und Rechenleistungs-Ressourcen vorgehalten, um neben den nativen Steuer- und Regelprozessen der konkreten Applikation über eine Anbindung an Netzwerktechnik (LAN) Applikation überwachen und steuern zu können. Dadurch können die üblicherweise notwendigen externen Schnittstellenbausteine entfallen. Für die Anbindung und Aufschaltung von externer Sensorik und Aktorik sowie von abgesetzten Bedieneinheiten sollen auch im Stand-Alone-Betrieb die Vorteile, wie für den vernetzten Betrieb bereits genannt, genutzt werden können.

The hardware platform formed according to the invention is composed of the following important functional units and characteristics:

• 1. A highly integrated micro-controller unit, which allows processing, verification and coordination of the bus data and the transmission to a SUB bus system for peripheral control in real time when using the UCU as a fieldbus node. By using the UCU as a stand-alone central unit, functional ports for digital, analog and time-discrete-modulated signals can be provided for the native control of the application placed thereon;
• 2. Two independent bus interfaces, which together with the aforementioned micro-controller unit as an innovation, the implementation of an active bus repeater for the intelligent management of the connected and registered fieldbus node through the function of targeted forwarding of bus data to the UCU units, similar to the function of a switch in other types of network allowed;
• 3. Galvanic isolation of the control components against bus interfaces and between the bus interfaces. Furthermore, the protection against ESD and differential transients should be ensured in order to ensure the highest possible operational safety;
• 4th fieldbus, which after the widespread EIA-485 standard can be performed to a high tolerance To ensure electromagnetic interference, cost-minimized bus wiring through standard control lines and fast data transmission over long distances (> 1 km). As a communication protocol, the Modbus protocol is used in RTU mode according to standardized specifications. Due to the fact that the "Modbus" represents the de facto standard in the industry and building automation, a high compatibility is ensured with most manufacturers of components and devices active in this area. The Modbus protocol should be superimposed with a data transport protocol, which allows the use of the innovative integrated repeater / switch function, without compromising the described compatibility.
• 5. For the use of the UCU as a stand-alone device, sufficient memory and computing power resources are kept available in order to be able to monitor and control the application in addition to the native control and regulation processes of the specific application via a connection to the network technology (LAN) application. As a result, the usually required external interface modules can be omitted. For the connection and connection of external sensors and actuators as well as remote control units, the advantages, as already mentioned for networked operation, should also be able to be used in stand-alone operation.

Although such bus master-controlled busses are typically easier to control because they have a single master, if that bus master should be disabled (eg, because it is held in reset or has failed), full access to the system resources behind the bus master is not longer available. For example, the manageability subsystem might not discover or update the state of the system resources behind the bus master.

Previously known field bus devices contain - in contrast to the present invention - no bus repeater, which per line only a limited number of participants is possible, the star line starting from a central unit per line, must be arranged. In order to increase the number of participants, these networks must always integrate external repeaters / hubs - which only behave in a passive manner and incur additional equipment and costs - with them.

For safety-related applications, fieldbus nodes are often used in ring topology - series connection - but this leads to low transmission rates, which are disadvantageous in time-critical applications. Furthermore, in the case of conventional fieldbus systems, one must pay close attention to whether and to what extent the grounding of the supply networks is carried out, because different types of grounding can impair bus communication until complete failure.

Depending on the application, the field devices must meet a wide variety of security requirements. To the respective safety requirements, eg the SIL standard - Security / Safety Integrity Level - according to IEC 61 508 suffice, the field devices must be redundant and / or diversified.

Redundancy means increased safety through double or multiple design of all safety-related hardware and software components. Diversity means that the hardware components located in the different measurement paths, e.g. a microprocessor, from different manufacturers and / or that they are of different types. In the case of software components, diversity requires that the software stored in the microprocessors be from different sources, i. H. from different manufacturers or programmers. All these measures are intended to ensure that a safety-critical failure of the measuring device as well as the simultaneous occurrence of systematic errors in the provision of the measured value is highly likely to be ruled out. It is also known, in addition to design individual hardware and software components of the evaluation redundant and / or diversified. Due to the redundant and diverse design of individual hardware and software components, the degree of security can be increased even more.

• • Bei der erfindungsgemäßen UCU handelt es sich um ein modulares System;
• • Durch den integrierten Busrepeater sind beliebige Bustopologien (Stern-, Baum-, Linien- oder Ringstruktur) mit unbegrenzt vielen Busteilnehmern ohne zusätzliche externe Repeater oder Hubs möglich;
• • Die Adresszuordnung erfolgt für den Errichter einfachst über Dezimal-Codiersteller am UCU;
• • Der aktive Repeater mit zusätzlicher Switch-Funktion weist sowohl eine permanent hohe Datenübertragungsgeschwindigkeit als auch Redundanz – im Sinne von hoher Sicherheit – auf, wofür eine Signalrichtungserkennung und -ausrichtung erforderlich ist;
• • Desweiteren ist dadurch bei sicherheitsgerichteten Ringbusformen die Erkennung und Abkopplung von gestörten Busleitungen oder Busteilnehmern möglich;
• • Durch die galvanische Trennung der Busschnittstellen auf der UCU muss nicht auf die Erdungsform der Versorgung Rücksicht genommen werden.

The following advantages are associated with the invention:

• • The UCU according to the invention is a modular system;
• • The integrated bus repeater allows any bus topology (star, tree, line or ring structure) with an unlimited number of bus users without additional external repeaters or hubs;
• • The address assignment is carried out for the installer simply via decimal coder at the UCU;
• • The active repeater with additional switch function has both a permanently high data transfer rate and redundancy - for the sake of high security - which requires signal direction detection and alignment;
• • Furthermore, with safety-related ring bus forms, the detection and decoupling of faulty bus lines or bus users is possible;
• • Due to the galvanic isolation of the bus interfaces on the UCU, it is not necessary to consider the earthing form of the supply.

The combination of integrated repeater / switch, input and output isolation and physical / unencrypted address assignment brings the installer significant advantages over existing systems that allow him to install and put into operation such systems without much training and special knowledge.

Ultimately, it is thus possible to offer the user not only a cost advantage through standardized volume devices but also an added benefit.

The field bus devices known from the prior art, in contrast to the present invention do not include a bus repeater, whereby per line only a limited number of participants is possible - which must be arranged star-shaped outgoing from a central unit. In order to increase the number of participants, these networks must always integrate external repeaters / hubs - which only behave in a passive manner and incur additional equipment and costs - with them. All components of the controller communicate with each other via an RS 485 bus system. The structure of the network corresponds to a line structure - a star or ring circuit is not allowed.

In the field of safety-related applications, field bus nodes in ring topology - series connection - are often used, but this leads to low transmission rates, which are to be regarded as disadvantageous especially in time-critical applications. Furthermore, in conventional fieldbus systems, it must be carefully considered whether and to what extent the grounding of the supply networks is carried out, because different types of grounding can affect the bus communication until complete failure.

The UCU according to the invention is a modular system with minimized component diversity, even for safety-relevant applications. Thanks to the integrated bus repeater, any bus topologies (star, tree, line or ring structure) with an unlimited number of bus subscribers without additional external repeaters or hubs are possible. The address assignment is carried out for the installer simply via decimal coder at the UCU. The active repeater with additional switch function should have both a permanently high data transfer rate and redundancy - in the sense of high security - for which signal direction detection and alignment is required. Furthermore, the detection and decoupling of faulty bus lines or bus subscribers is possible in the case of safety-related ring bus forms.

Due to the galvanic isolation of the bus interfaces on the UCU, it is not necessary to consider the earthing form of the supply. Ultimately, this makes it possible to offer the user a cost advantage through standardized volume devices.

The invention is illustrated below with reference to some drawings. These show in

1 a UCU as a fieldbus controller for displaying the repeater functionality in the "tree" topology,

2 a detail of the bus structure of 1 with multiple feeders both grounded and ungrounded,

3 a UCU functional block diagram with both fieldbus node central unit and with stand-alone central unit with network access and

4 Combinations of different bus topologies.

In 1 a bus coupler with integrated repeater is shown, with the result that no external repeater or hub is necessary. The integrated repeater function allows a freely expandable topology.

2 shows a detail of the bus structure with multiple network feeds. The bus nodes are galvanically isolated and assume a repeater function. In the low voltages of different classes grounding is allowed.

The upper area of 3 shows the use of a UCU as a fieldbus node central unit (dot-dashed boundary), while in the lower area (dashed lines) the use of the UCU is shown as a stand-alone central unit with network access.

In 4 shows the possible combination of different bus topologies - ring, line and tree.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been 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

• WO 03/098154 [0011]
• WO 96/12993 [0012]
• DE 102007003196 A1 [0013]

Cited non-patent literature

• EIA-485 standard [0018]
• SIL standard - Security / Safety Integrity Level - according to IEC 61 508 [0022]

Claims (2)

Universal control unit (UCU) with at least one interface for connection to another UCU and / or to a bus line and / or to a control terminal. Universal control unit according to claim 1, characterized by a BUS coupler with integrated repeater.

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