WO2009124560A1

WO2009124560A1 - Communication device and network

Info

Publication number: WO2009124560A1
Application number: PCT/EP2008/002775
Authority: WO
Inventors: Stefan Klehr
Original assignee: Siemens Aktiengesellschaft
Priority date: 2008-04-08
Filing date: 2008-04-08
Publication date: 2009-10-15

Abstract

The invention relates to a communication device (401) comprising a network connection (420). In order to couple data output signals of an interface module (320) to the network connection (420), the interface module (320) is connected to a primary winding (14), comprising several windings, of a transformer (10, 360) and the network connection (420) is connected to a secondary winding (16), comprising several windings, of the transformer (10, 360). The primary and the secondary windings (14, 16) have a common core (12) and to increase the safety in a explosion-prone area, the windings of the primary winding (14) are at a minimum distance from the windings of the secondary windings (16).

Description

description

Coordination device and network

The invention relates to a communication device with a network connection, wherein for transmitting data output signals of an interface module to the network connection of the interface module having a multi-turn primary winding of a transformer and the network connection with a multi-turn secondary winding of the transformer is connected to the. Furthermore, the invention relates to a network with a plurality of communication devices.

Communication devices can be combined to form a network, for example via Twisted Pair Ethernet lines, which are connected via an Ethernet connection. In order to make such a network suitable for use in potentially explosive atmospheres, it is necessary to consider all possible circuits which may arise in the entire network, for example by superposing possible voltages and / or currents. Due to the multitude of combinations, this approach presents the network's observer responsible for the explosion protection with a computationally intensive and non-economic error consideration of such a network. This holistic view of all electrical circuits and thus all interconnected devices with a coordinated limitation of the overall performance has proven to be very complex.

Another prior art solution, such as e.g. An optical fiber-based Ethernet, ie a network with fiber optic galvanic isolation, has the disadvantage that the communication devices and the necessary optical waveguides are very cost-intensive.

It is therefore the object of the invention to provide a network which is in an explosive environment can be used and the effort for the error consideration of the network is reduced.

According to the invention the object is achieved in that for a network which is to be operated in a hazardous environment, a communication device having the features of claim 1 is used. In the communication device with a network connection, wherein for transmitting data output signals of an interface module to the network port, the interface module is connected to a primary winding of a transformer and a secondary winding of the transformer is connected to the network connection, wherein the primary and secondary windings have a common core To increase safety in a potentially explosive environment, the turns of the primary winding to the turns of the secondary winding are arranged in a minimum distance. This minimum distance may preferably be 160 μm, preferably more than 167 μm, in particular more than 180 μm, in particular more than 200 μm, in particular more than 500 μm. So there should be a defined minimum distance between the times, this is to be accomplished for example by insulation material. The turns of the primary winding should preferably have an insulating material with a thickness of 180 microns. If several communication devices are connected to each other via so-called intrinsically safe network connections in a potentially explosive environment, a safety-related consideration must be carried out. This means that all possible circuits, which can arise via connecting lines between the communication devices, are evaluated for their ignitability. Even if each network connection itself is intrinsically safe in voltage and current limited, but it can come through the interconnection of multiple communication devices to critical circuit overlays. Such circuit overlays can be avoided by means of a safe electrical isolation, as it is realized by the primary winding and the secondary winding of the transformer. The following is for the handyness transformer the term transformer module introduced. A transformer module is a module with several transformers, eg a combination of individual transformers for a transmission path and a combination of several individual transformers for a reception path. The transformer module can be regarded as an exchangeable, complex part, which forms a closed functional unit. The transmission module can also combine several transmitters for several network connections. The data output signals of the interface module are electrically isolated from the network connection by the transformer module. Preferably, each communication device which is present in the network has a transformer module for galvanic isolation. By using a transformer module, in which the turns of the primary winding and the secondary winding do not fall below the predetermined minimum distance, the transformer or the transformer module can be regarded as a component with a countable error for error consideration. With the communication device configured in this way, error consideration for individual network segments can now be carried out. The time-consuming and computationally intensive overall view of the complete network is greatly simplified by the galvanic separation and the resulting split into individually viewable link segments. It is also advantageous that for the consideration of such a link segment under "worst-case" conditions, for example, with a maximum segment length of 100 m, a maximum inductance of the cable of, for example, 0.2 microns / 100 m, so you can perform an exemplary safety assessment and transfer the result to additional link segments. A network constructed with such link segments can then be considered secure.

Since the circuits within the link segment also have to be "enabled" by suitable measures for intrinsic safety, in an advantageous embodiment, a longitudinal switch between the interface module and the transformer module is required. derstand arranged in a series circuit. For the consideration of inductances occurring in a transmission path, for example, a four-wire Ethernet cable is arranged as the connection of two communication devices to form a link segment. Each communication device has a network connection, so that the Ethernet signals carry the following transmission path: Interface module - transmitter module - network connection - Ethernet cable - network connection - transmitter module - interface module. In the signal path described above, which represents a circuit, an inductance of the transformer module decreases with increasing current. As a result, the effective inductance in the safety-relevant circuit is just then low when safety-related currents flow. This effect allows the use of larger ignition limit curves for inductive circuits. Thanks to the higher ignition limit curves, it is preferable for series resistors having a resistance value in the range of a few ohms to be sufficient. These series resistors are advantageously connected to a TX or RX output of the interface module and connect the TX or RX line to the transmitter module.

In a further advantageous embodiment, a limiting means is arranged for limiting the current and voltage of data input signals for the interface module. Such limitation means, which are also called barriers, limit at all device-side terminals of the interface module the incoming currents in the interface module and voltages to certain maximum values, such as 240 mA and 4 V. This can be an intrinsically safe communication device as defined in current and voltage limited Unit, which is also galvanically isolated from other communication devices. In a link segment formed by a plurality of communication devices connected in series, however, the devices connected in the link segment are nevertheless not galvanically connected to one another, for example in the case of a short-circuit of a transformer module, since the link corresponding to the short-circuited transformer module. transmitter module maintains galvanic isolation. Circuit overlays due to a faulty interconnection of two communication devices via an Ethernet cable can therefore not occur because at least one of the two transformer modules is safely galvanically isolated.

Furthermore, it is advantageous that a communication device is equipped with a limitation of a supply voltage for the interface module. Advantageously, a current limiter is connected in a supply line of the supply voltage for the interface module. Also conceivable is an electronic current and voltage limitation with a rectangular characteristic or a trapezoidal characteristic.

Furthermore, it is advantageous that the communication device has a transformer module with a transmission bandwidth of 0.1 to 100 MHz. Especially for networks with large amounts of data, a large transmission bandwidth is an advantage.

It is also advantageous for the transmission characteristics of the transformer module if the electrical conductor of the primary winding or that of the secondary winding has a solid insulating material. In order to establish the necessary distances between the turns of the secondary winding and the primary winding, it may be advantageous to use a material made of Teflon. A material made of Teflon or a Teflon-like material favors the high-frequency properties of a transformer module and keeps the losses low. In the standard EN 60079-11 a "solid" insulation material is required for transformers, preferably a "solid" insulation material with Teflon can be realized.

A powerful communication network, which permits high transmission data, is used to advantage in a potentially explosive environment. This network has communication devices with the aforementioned advantages. Preferably, at least two communication devices are interconnected via Ethernet lines and form an independent intrinsically safe segment.

Further advantageous embodiments of the communication device and the network are explained in the drawings and the associated descriptions. Show it:

FIG. 1 shows a transformer module, FIG. 2 shows minimum distances of different windings to the transformer module, FIG. 3 shows a transmission path, and FIG. 4 shows a network with communication devices.

According to FIG. 1, a transformer 10 for the galvanic isolation of output signals of an interface module 320 explained in greater detail in FIG. 3 is represented by a wired network. On a designed as a ring core 12, a primary winding 14 and a secondary winding 16 are applied. The primary winding 14 is shown as a somewhat thicker conductor than the conductor of the secondary winding 16. The primary winding 14 and the secondary winding 16 are wound as a bundle around the annular core 12 of the transformer 10. In the winding geometry shown here, the conductors of the primary winding 14 and the secondary winding 16 on crossing points. At these crossing points, a minimum distance of about 0.2 mm to the conductor of the primary winding is maintained by an insulating layer applied to the conductor of the primary winding. This minimum distance is maintained by the insulating layer also to the core 12, so that meets the

Transformer 10 the condition that for a safety-related consideration according to the standard EN 60079-11, the transformer may be considered as a component with a "countable" error. The core 12 has a highly permeable core material.

FIG. 2 is a schematic representation of the arrangement of a first embodiment of the primary winding 14 and the secondary winding 16 of FIG. 1 to illustrate the minimum distance between the two conductors. th winding wire 22 to a second winding wire 24. The first winding wire 22 corresponds to the conductor of the primary winding 14 and the second winding wire 24 corresponds to the conductor of the secondary winding 16, wherein in this embodiment, an insulation 26 of the same thickness for both winding wires 22 and 24 has been selected. The distances x, y and z in this case represent the layer thicknesses of the insulating material. In order to set the desired transmission properties of the transformer module, the layer thicknesses x, y and z can be configured in various variations and combinations.

According to FIG. 3, a transmission path 300 is shown. The transmission path 300 shows the path of a connection, starting from an interface module 320 of a communication device 400, as shown in detail in FIG. 4, to another communication device 401, wherein only the transmitter module 360 of the further communication device 401 is shown in this illustration. The interface module 320 provides data output signals via its TX + and TX- ports. These

Data output signals are fed to the transmitter module 360 via series resistors 330. The series resistors 330 have a value of 2.5 ohms. The transformer module 360 is configured in this embodiment of several transformers according to FIG. A transmitter for a transmission direction TX and a transmitter for a reception direction RX. To connect the transmitter module 360 of the first communication device 401 to the transmitter module 360 'of the further communication device 400, a cable route 370 is connected to the respective network connection sides of the transmission module 360 or 360'. This cable route 370 is designed as a twisted pair Ethernet cable in a four-wire version.

For a corresponding signal conditioning at the data outputs TX + to RX- of the interface module 320 additionally provide Pullupwiderstände 340. These pull-up resistors 340 are each connected to the supply voltage VCC. As data input signals, the interface module 320 receives data input signals via a seven-wire RMII bus 380. These data input signals are limited by a limiting means 310 in current and voltage. Via the interface module 320, the limiting means 310 prevents critical currents and voltages from entering the signal path between two communication devices. A possible ignition by possibly skipping discharge sparks in a hazardous area is thus avoided. A voltage limiter 305 limits the supply voltage VCC necessary for the communication device.

By means of the two transformer modules 360,360 ', one each for a communication device, the communication devices are galvanically isolated from each other. By this galvanic

Separation, the transmission path for fail-safe viewing can be considered as a link segment.

4 shows a network 410 with Ethernet cables 430 for operation in a potentially explosive environment. To a switch 400, a first communication device 401, a second communication device 402, a third communication device 403 and a fourth communication device 404 are connected in a star shape via the Ethernet cable 430. The fourth communication device 404 has in this example two network ports 420, which are designed as Ethernet ports. This dual version of the Ethernet ports allows networking as a line structure. For networking as a line structure, it is crucial that the fourth communication device 404 has a transmitter module 360 for each signal path. By means of these transformer modules 360, the galvanic separations of the individual link segments 440 are ensured.

The internal structure of the communication devices 401 to 404 will be explained using the example of the first communication device 401. The first communication device 401 has the interface module 320 already described with FIG Barrier for the power supply 310a, the supply voltage applied to the interface module 320 is limited to current and voltage. Another barrier to the data supply 310b limits the currents and voltages associated with the data input signals to the interface device 320 with respect to their maximum currents and voltages. The data output signals of the interface module 320 can thus be fed to the network connection 420 via the transmitter module 360 with intrinsically safe current and voltage values.

In the figures, the same parts are provided with the same functions in different devices with the same reference numerals.

Claims

claims

Communication device (401) with a network connection (420), wherein for transmitting data output signals of an interface module (320) to the network connection (420), the interface module (320) with a primary winding (14) of a transformer (10, 360) and the Network connection (420) to a secondary winding (16) of the transformer (10, 360) is connected, wherein the primary and the secondary winding (14, 16) have a common core (12), wherein to increase the safety in a hazardous Environment the turns of the primary winding (14) to the turns of the secondary winding (16) have a minimum distance.

2. Communication device (401) according to claim 1, wherein between the interface module (320) and the transformer (10, 360), a series resistor (330) is arranged in a series circuit.

3. Communication device (401) according to claim 1 or 2, wherein for limiting the current and voltage of data input signals for the interface module (320) a limiting means (310) is arranged.

4. Communication device (401) according to one of claims 1 to

3, wherein for limiting a supply voltage (VCC) for the interface module (320) a voltage limiter (305) is present.

5. Communication device (401) according to one of claims 1 to

4, wherein the transmitter (10, 360) is designed for a transmission bandwidth of 0.1 to 100 MHz.

6. Communication device (401) according to one of claims 1 to 5, wherein the electrical conductor of the primary winding (14) and the secondary winding (16) has a solid insulating material.

7. Network (410) for use in a potentially explosive environment with a communication device (401) according to one of claims 1 to 6.

The network (410) of claim 7, wherein at least two communication devices (400, ..., 404) are interconnected via Ethernet lines (430) and form an independent intrinsically safe segment (440).