Electrical transmission or interconnection systems – Electromagnet or highly inductive systems
Reexamination Certificate
1999-11-09
2002-11-05
Fleming, Fritz (Department: 2836)
Electrical transmission or interconnection systems
Electromagnet or highly inductive systems
C340S315000, C439S950000
Reexamination Certificate
active
06476520
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
not applicable
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH AND
DEVELOPMENT
not applicable
REFERENCE TO A “MICROFICHE APPENDIX”
not applicable
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a plug connection for a hazardous location for energy and data transmission between at least one electrical load and a bus system, having a primary part and secondary part constructed as transmitters, the primary part and secondary part being separable and connectable and with a converter associated with the primary part, and to an energy and data transmission method for hazardous locations, in which energy and data can be transmitted by means of a bus system to a primary part of at least one such plug connection and which energy and data are transmittable from a secondary part of the plug connection to at least one load.
A comparable plug connection for energy and data transmission is known from DE 40 33 052 C2. The known plug connection has a transmitter with a primary and a secondary part, which are separable and usable in combination. The primary part also has a converter means for the demodulation of data transmitted from the load cell as a sensor to the evaluating unit. However, this known plug connection is not intended for a hazardous location and is also not designed for such, because e.g. there are no limiting means for the electrical quantities to be transmitted.
It is necessary in numerous applications to transmit energy and data to loads in hazardous locations. In the present sense loads generally means sensors and actuators. Reference is made in exemplified manner to level gauges for oil or liquefied petroleum gas tanks.
2. Description of the Related Art
Numerous transponder methods are known, in which receivers located in hazardous locations are activated in an intrinsically safe manner by radio data and energy transmission. The energy necessary for transmitting back a response of the receiver, is also transmitted by means of the RF transmitted power. For this purpose the receiver has corresponding antenna. However, the transmitted power is so low that in general no sensors or actuators can be operated.
Therefore proposals have already been made for carrying out the energy and data transmission to such sensors or actuators using bus systems. A lecture by Mr. Cramer Nielsen at the “2nd International Conference on P-NET Field Bus Systems” on Nov. 30, 1992 and Dec. 1, 1992 in Deggendorf disclosed a field bus system for intrinsically safe, explosion-proof loads. The overall bus system corresponds to the requirements of “IS-16, intrinsically safe P-NET bus”. It is therfore completely constructed in the type of protection “intrinsically safe”. Energy and data are jointly transmitted by means of a two-wire bus line. The associated plug connection operates inductively and has two facing coils in cup cores. However, as a result of the construction in the type of protection “intrinsically safe” the efficiency of this bus system is not very high. As this type of protection only allows an extremely low electric power, it is only possible to connect a relatively small number of loads to the bus system. It is in particular impossible with this bus line system to supply loads with a type of protection other than “intrinsically safe” or with no type of protection and correspondingly increased power consumption data in addition to loads constructed in intrinsically safe and explosion-proof form. Therefore the flexibility of this transmission system is very low. As energy and data are transmitted on the same line, the maximum information density of the bus system is also reduced. As a result of dispersion in lines or electronic components there is also a mixing of signals. This can only be obviated by reducing the number of bus nodes to be supplied or reducing the data transmission rate. However, both measures are highly undesired.
DE-43 44 071 A1 discloses a transmission system for hazardous locations. In this system the bus system is once again constructed in an intrinsically safe, explosion-proof manner and consequently has the same disadvantages as described in the preceding paragraph.
EP 0 666 631 A2 discloses a supply system for a field bus in hazardous process engineering installations. Energy and data are transmitted via the same pair of wires. On the way from a waiting bus to the terminals for intrinsically safe, explosion-proof loads, current and voltage limiting means are arranged in spatially separated manner. One of the limiting means is located in a distributor immediately upstream of the connections for the loads. Optionally said limiting means can be obviated or modified, so that also loads, which are constructed in a type of protection other than “intrinsically safe” or with no type of protection can be connected. However, it is disadvantageous that for each connection the maximum transmittable electric power is fixed and also either the current or the voltage is highly limited even for the not intrinsically safe connections.
DE 27 52 783 B1 discloses a plug connection for medical equipment, e.g. for transmitting ECG signals to an evaluating unit. In this plug connection the energy transmission from the equipment takes place with a corresponding energy supply part via an inductive transmitter to the secondary part. In said equipment data transmission takes place by means of an optoelectronic line, e.g. from the ECG, via the secondary part to the primary part. However, this equipment neither has limiting devices, particularly for the energy transmission, nor is there a bidirectional data transmission. Thus, this equipment is unsuitable for hazardous locations.
The document “der elektromeister+deutsches elektrohandwerk, 1985, No. 6 pp 349 to 352” discloses requirements for installations in hazardous locations. However, the barriers provided therein solely constitute wired-in current-voltage barriers, which can only be used to a limited extent for data transmission. It provides no teaching as to how a plug-in data and energy transmission device should be designed for hazardous locations.
DE 36 44 868 A1 relates to a connection for a subscriber to a local network. However, this document only discloses a two-wire line by means of which energy and data are transmitted, so that this leads to a considerable limitation when transmitting energy and data. In addition, the corresponding connection is not of the plug-in type, so that the desired flexibility for an easy adaptation for the power requirement of different sensors or actuators does not exist.
BRIEF SUMMARY OF THE INVENTION
Therefore the object of the invention is to overcome the preceding disadvantages and provide a plug connection for energy and data transmission for loads such as sensors and actuators in hazardous locations, in which a high efficiency and flexibility are provided by said plug connection. In addition, an energy and data transmission method for hazardous locations is to be provided, with which a high reliability can be achieved.
According to the invention, this object is achieved with a plug connection for a hazardous location for energy and data transmission between at least one electrical load and a bus system, having a primary part and secondary part constructed as transmitters, the primary part and secondary part being separable and connectable and with a converter associated with the primary part, as a result of its having the features of the bus system being connected to the plug connection in each case via separate energy and data supply lines, at least in the primary part limiting means being provided for the electrical quantities to be transmitted, and at least the secondary part being associatable with the hazardous location. In the case of an energy and data transmission method for hazardous locations, the object is achieved by the features that in the primary part the type of protection of the connected load is determined and that the electrical quantities to be transmitted are limited to maximum values corresponding t
Barlian Reihhold A.
Böhm Alfred
Lang Rainer
BARTEC Componenten und Systeme GmbH
Fleming Fritz
Jacobson & Holman PLLC
Rios Roberto J.
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