GB2198569A

GB2198569A - Network for data-and energy transmission

Info

Publication number: GB2198569A
Application number: GB08721735A
Authority: GB
Inventors: Siegfried Schwarz
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-09-16
Filing date: 1987-09-16
Publication date: 1988-06-15
Also published as: DE3631477C3; GB8721735D0; DE3631477C2; FR2604047A1; DE3631477A1

Abstract

The transmission of data and energy takes place via separate or the same lines 10, and the users 24 of the network do not themselves supply any energy into the network. For transmission, the users successively modulate the supplied energy. The energy consumption of the users is minimised through the data transmission procedure, in which the users are successively set into operating state and after completion of the required action automatically return into the "ready for operation" state with lower energy consumption. <IMAGE>

Description

NETWORK FOR DATA- AND ENERGY TRANSMISSION The invention relates to a network for the transmission of data and energy via separate or the same lines, whereby in particular the data of apparatus in measurement, control and regulation technology are transmitted and their energy supply is ensured.

In such networks, the data and the energy from distant sensors, actuators, apparatus and computers are exchanged and supplied via the network.

It is known, to transmit data in measurement, control and regulation technology of sensors, actuators, apparatus and computers via 4 to 20 mAinterfaces in an analog manner. It is also known, to transmit these data digitally via the serial interfaces RS 232, V 24. Thereby, frequently energy is transmitted to the remote apparatus in both cases with additional lines.

It is also known, to transmit the data and the energy of sensors in areas protected against explosion according to NAMUR, via the same lines. In all cases, the data are only transmitted between two points. In the networks which have become known for measurement, control and regulation technology (cf. DE-OS 34 27 350, DE-OS 33 33 847, DE-OS 33 13 240) the network drivers during transmission supply energy into the network.

They are therefore less suitable for the transmission of data and energy, because they require a high degree of energy for transmission. In addition, they do not contain any elements, which permit the minimization of energy in the network and the allocation of different energies.

The invention is based on the problem of improving the transmission of data and energy with networks of control, measurement and regulation technology.

The problem is solved according to the invention in that at least one central supply apparatus supplies the users of the network and their network drivers with energy and all users of the network within the scope of their access authorisation successively modulate this energy for data transmission, without themselves supplying energy into the network.

A remarkable advantage lies in that even computers in areas at risk of explosion are able to operate without their own voltage supply. In these endangered areas, network- or supply apparatus can be dispensed with, because the supply takes place via the network of the networked computers.

In order to minimize the energy of the network, the users must differentiate at least three states, to reduce the energy taken up by them, namely in operation, ready for operation and out of operation with storage of the operation data. The received energy from the users is modulated for a data transmission and distributed to all users.

The advantages achieved by the invention lie in particular in that with a single BUS, ring or tree network a plurality of users can be connected and thereby not only is the transmission of data between them made possible, but also the supply of energy of the apparatus can take place (via this network).

Advantageously, the supply of energy takes place in the centre of the network.

The possibility of data transmission in the network is further improved in that the network driver contains a transmission collision detector.

The flexibility of the data transmission via the network is increased in that the network driver contains a device, which undertakes an automatic switchover of access as a function of the network load.

Preferably, the users have interface circuits, which are known in the art as UART or respectively USART. These interface circuits are then coupled via the network driver with the network.

In a preferred form of embodiment of the network according to the invention, the users may be CMOS-single chip computers, preferably of the type

INTEL/8051 with serial interface UART.

In such a network, one and the same protocol can be used for data and energy transmission or only for data transmission, whereby only levels 1 of the ISO model are adapted such that for the transmission of data and every another network driver is used.

Preferred embodiments of the user according to the invention are disclosed in the subclaims.

Further characteristics and advantages of the user according to the invention and its coupling to the network can be seen from the following description of the embodiments by means of the drawings.

Figures 1A and 1B are a schematical logical list of instructions for use of the computer.

These minutes as in Figure 1A of the request, of the storage 1 and the reply, storage 5 is identical and thus symmetrical. In principle the minutes/list of instructions as shown in Figure 1B can also be asymmetrical. In this case, the requesting master waits for the reply from the slave.

Figure 2 is a schematical drawing of an embodiment of a network with users according to the invention.

In the known network drivers, the data from and to the user immediately passes the network driver. In order to be able to eliminate the processor in the network, as is the case in the present invention, the network driver has to take over various tasks. These tasks are explained in Figure 1 by a simple print-out.

The tasks are performed in the following order: 1. Storage of the destination address in the user memory and comparison with its address.

2. Storage in the memory of the data which follows the valid destination address and starting the request and/or command 2, if necessary.

3. Execution of command 3 by means of which data security of 1 becomes valid.

Transmitting the source address and subsequently the destination address of memory 5 as a reply of the user whereby the access priority of the requesting or of the commanding user is taken over.

Latest termination of request 4 and adding of the request data to the reply, memory 5 of the user.

Formation of data-security of the reply, memory 5, from destination address, source address and the data of request, and addition of the data-security to the user reply.

The aforementioned tasks do not depend on the access method used in the network. Network access may take place according to the master-slave principle, the CSMA/CD or the token passing method. Then the token passing method is used, the network driver has to accomplish a further task: Redirection of the token to the requesting, commanding user on completion of the reply.

In the described method the user always functions as a slave. Its access to the network is established by a request or a command by a second user which is a master. The user may, however, establish network access itself and transmit the reply.

As an example, a sensor is named here which establishes network access itself when its admissable limit values are exceeded.

The print-out (Figure 1) of the request, memory 1, and of the reply, memory 5, are identical and thus symmetric. In general, the print-out, as shown in Figure 2, may also be unsymmetrical. In this case the requesting master waits for the reply by the slave.

Figure 2 shows a user 24 with computer 20 with connection to a network 10. The figure shows the following elements of the user 24 : a transmitter 12, a network driver 14, an address switch 16, an energy storage unit 18, the computer 20 and a sensor 22.

The transmission of data and energy takes place via the network 10 and the transmitters 12; thereby the network 10 is supplied centrally by at least one source of alternating-current voltage. On transmission of a user 24, the latter modulates, for example the amplitude of the alternating-current voltage in the NRZ code.

The network driver 14 supplies the user 24 with at least one stabilised direct-current voltage 31,36.

Thereby a condenser 18 and/or an accumulator serve as energy stores for this direct-current voltage. The maximum current to each user 18 is limited in the network driver 14 so that in the case of a shortcircuit of one or more users 24, the transmission of data and energy to the other users 24 is not disturbed.

The network driver 14 only passes on to its user 24 the data which are intended for the latter. For this, the network driver 14 contains the address switch 16.

If the destination address of a message coincides with the address of a user 24, then this user 24 is transferred from the "ready for operation" state into the "in operation" state. This takes place through the address-interrupt command, e.g. via line 32. The computer 20 performs the required operation through initiating the address-interrupt, and thereafter automatically switches back into the "ready for operation" state, with reduced energy consumption. The control of the sensor 22 is effected through the computer 20, in parallel or in series. The sensor 22 may monitor a random magnitude, which is applied to the computer as a signal.

If the network 10 fails, then the operational parameters of the computer 20 are maintained through the stored energy in the energy storage unit, namely the accumulator 18. In order that this energy is sufficient for a long period of time, the computer 20 is switched by the network driver 14 with the command "power down", for instance on line 33, into the "out of operation" stage, until a new address is transmitted.

In the "out of operation" state, the computer 20 takes up the least possible energy.

The data transmission between the network driver 14 and the computer 20 may take place in series or in parallel. In the simplest case, the data in the figure are transmitted in series as transmission data, e.g.

via line 35 and as receiving data e.g. via line 34.

In the case of a user 24 without computer 20, the sensor 22 is connected directly with the network driver 14. The network driver 14 must thereby take over the control of the sensor 22.

Claims

CLAIMS:

1. Network for control, measurement and regulation technology for the transmission of data and energy via separate or the same supply and return lines, characterised in that at least one central supply apparatus supplies the users of the network and their network drivers with energy and all users of the network within the scope of their access authorisation successively modulate this energy for data transmission, without themselves supplying energy into the network.

2. Network according to Claim 1, characterised in that the supply of the users takes place with alternating current voltage.

3. Network according to Claim 2, characterised in that the users are separated with transformers galvanically from the network.

4. Network according to Claim 2 or 3, characterised in that the half-wave cycle of the alternating-current voltage serves to supply the users and also serves for the synchronization of the data and their cycle.

5. Network according to one of Claims 2 to 4, characterised in that from the alternating-current voltage at least one regulated direct-current voltage is produced, the maximum current of which is limited such that the short-circuit of one or more users of the network does not endanger the data transmission of the remaining users of the network.

6. Network according to one of Claims 1 to 5, characterised in that the users differentiate at least three stages to reduce their consumed energy, namely "in operation ", "ready for operation" and "out of operation" on storage of the operation data, and the energy taken up by a user is controlled throughout the data transmission and the energy is distributed to all users.

7. Network according to one of Claims 1 to 6, characterised in that each network driver to reduce the energy of its user checks, acting for its user, whether the destination address of a message is valid for its user and only then converts its user from the "ready for operation" state into the" in operation" state, when the destination address coincides with the address of the user, whereby the user takes over the message, performs the required operation and after its completion automatically returns into the "ready for operation" state with a lower energy consumption.

8. Network according to one of Claims 1 to 7, characterised in that on failure of the central supply apparatus each user is converted by its network driver into the "out of operation" state with lowest energy consumption, whereby the operation data are maintained owing to its accumulator, until the network driver converts the user back into the "ready for operation" state after receipt of a destination address.

9. Network according to one of Claims 1 to 8, characterised in that the supply of energy takes place in the centre of the network.

10. Network according to one of Claims 1 to 9, characterised in that the network driver contains a transmission-collision detector, which controls the access to the network.

11. Network according to one of Claims 1 to 10, characterised in that the network driver contains a device, which undertakes an automatic switchover of access as a function of the network load.

12. Network according to one of Claims 1 to 11, characterised in that the users are coupled with their UART, USART via the network driver with the network.

13. Network according to one of Claims 1 to 12, characterised in that the users contain a CMOS-sinqle

chip computer with serial UART, e.g. the INTEL/8051.

14. Network according to one of Claims 1 to 13, characterised in that for a network for data and energy transmission or only for data transmission one and the same protocol is used, whereby only levels 1 of the ISO model are adapted, in that for the transmission of data and energy a different network driver is used.

15. Network according to one of Claims 1 to 14, characterised in that the network driver not only undertakes the address recognition and passes the data on to its user, but also automatically to transmit data to an enquiry without intercalation of the computer responds with received data, and appends this to the enquiring telegram.

16. User in a network which replies to a second requesting and/or commanding user via a network driver as a slave characterised in that the network driver itself controls and/or questions the request and/or command units and redirects the requested reply, without having a processor.

17. User according to Claim 16 characterised in that the user as a salve adds its reply to the request or the command of a second, calling user by taking over its access priority to the network.

18. User according to Claim 16 or 17 characterised in that the network driver stores the destination address which is called and compares it with the user address.

19. User according to Claim 18 characterised in that the network driver stores the incoming data on receipt of a valid destination address and initiates the request to be carried out and/or the command.

20. User according to Claim 19 characterised in that the network driver carries out the command on the basis of the data if the data security is valid.

21. User according to Claims 16 to 20 characterised in that the network driver transmits the reply either at first the source address stored and then the destination address, thereby taking over the access priority of the requesting, commanding user, or it starts transmission of the reply without address.

22. User according to any of the preceding Claims 16 to 21 characterised in that the network driver terminates the request and adds the request data to the reply.

23. User according to any of the preceding Claims 16 to 22 characterised in that the network driver forms the data-security from the transmitted reply and adds it to the reply as a termination.

24. User ac cording to any of the preceding Claims 16 to 23 characterised in that the second user which calls in the network driver, can establish network access according to the central master principle, according to the CSMA/CD method or according to the token passing method.

25. User according to Claim 24 characterised in that in the token passing method as network access, the network driver returns the access priority, the token, to the requesting, commanding user after its reply.

26. User according to any of the preceding Claims 16 to 25 characterised in that the network driver itself comprises all components required in order to be able to receive the request and/or command of the second user, to carry out the command, to form the request data and to redirect the request data as a reply to the second user.

27. User according to any of the preceding Claims 16 to 26 characterised in that the user functions as a sensor and/or actuator.

28. Network substantially as hereinbefore described with reference to the accompanying drawings.