WO1995012260A1

WO1995012260A1 - Circuit and construction arrangement for bidirectional contactless, wireless transmission of information across rotating/stationary axes between the various units of industrial actuating and process control equipment

Info

Publication number: WO1995012260A1
Application number: PCT/HU1994/000047
Authority: WO
Inventors: László BECK; Tibor FRAKNÓI; János P. HORVÁTH; Zoltán NÉMETH; László TÁRNOK; István VARGA; Kálmánné DÓSA; László RUMPLER; József SZTANKÓ; László FANCSALI; Gábor KOVÁCS
Original assignee: Hns Müszaki Fejlesztö Kft
Priority date: 1993-10-27
Filing date: 1994-10-27
Publication date: 1995-05-04
Also published as: HU9303047D0; HU216214B; HUT70226A; AU1074795A

Abstract

The invention relates to a circuit and a construction arrangement for bidirectional wireless transmission of information, through rotating/stationary axes between different units of industrial actuating and process control equipment said arrangement incorporating two information forwarding, transmitting and converting main units (IA, IB) preferably of identical design, each consisting of a power supply unit (1A, IB), an optical receiver unit (2A, 2B), a direction coupling unit (3A, 3B), and an optical transmitter unit (4A, 4B), where the optical transmitter unit (4A) located in one of the two information forwarding and converting main units (i.e. IA) constitutes a transmission channel with the optical receiver unit (2B) located in the other information forwarding and converting main unit (IB) while the optical transmitter unit (4B) located in the other information forwarding and converting main unit (IB) constitutes a transmission channel with the optical receiver unit (2A) located in said one of the two information forwarding and converting main units (i.e. IA).

Description

CIRCUIT AND CONSTRUCTION ARRANGEMENT FOR BIDIRECTIONAL CONTACTLESS, WIRELESS TRANSMISSION OF INFORMATION ACROSS ROTATING/STATIONARY AXES BETWEEN THE VARIOUS UNITS OF INDUSTRIAL ACTUATING AND PROCESS CONTROL EQUIPMENT

Field of the invention

The invention relates to the circuitry and con¬ structional arrangement for bidirectional contactless transmission of information across rotating/stationary axes between the various units of industrial actuating and process control equipment.

The circuit arrangement and construction complying with the invention can advantageuosly be applied in automatic manufacturing machines, multi-axle machine tools, industrial robots, where information is to be transmitted between the stationary actuating and process control equipment and the peripheral units switching and sensing elements rotating with respect to said equipment around a given axis.

Prior art of the invention

The need for transmitting a considerable number of information between parts rotating with respect to each other often arises in control and regulating engineering. Between the various units of up-to-date programmable logic control equipments, such as between those of the product of GE-FANUC, ALLIAN-BRADLEY (A-B) , AIG-MODICON, SIEMENS, etc. information transmission takes place through a bus system, and since all inter- connected units are coupled to the same line of trans¬ mission, the exchange of information betwen any two units can be accomplished through that line.

From that it follows that at any point of the line information can pass in either direction at a high trans- mission speed (at frequencies approaching the MHz level) rendering very high-speed forwarding of information possible.

In control engineering systems representing the present state of the art the transmission of information takes place through devices establishing physical contacts. The contacts between units rotating with respect to each other are realized by means of brush contacting with rotary-slip rings.

The disadvantage of the above arrangements is that mechanical contacts may become uncertain, especially when a large amount of information is to be transmitted to which a very large number of contacts have to be established, further at higher frequencies considerable nois levels are produced. Mechanical wear of contacts and their contamination impede reliable flow of current through these contacts.

In addition to all this, the connection through contacts require frequent cleaning, whereby the maintenance costs are increased. There are several known arrangements and equipments for contactless data transmission as well.

Such an arrangement has been described in DE OS 30 1370 5 "Anordnung zur ϋbertragung von Daten zwischen einem mobilen Datenenfassungsgerat und einem Daten- verarbeitungsgerat".

Essentially, here the data are recorded in a mobile data recording device without establishing electrical connection between the data recording device and data processing device. This is accomplished by arranging-the data, trans¬ mitting part of an adapter and of a data recording device in close vicinity to each other and placing translucent disks are placed so that both in the movable data re¬ cording device and in the adapter, behind the translucent disks, a transmitter diode and a receiver diode both working in infrared range, are arranged in such a way that the infrared transmitter diode of an equipment is placed opposite to the receiver diode of the other equipment. The disadvantage of this arrangment lies in that this optical connection can not be used for bidirectional contactless, wireless transmission of in¬ formation.

A similar solution is described in DE OS 3623666 "Verfahren zur bidirektionalen Datenϋbertragung und danach arbeitendes elektronisches schloss-Syste ".

Here, the bidirectional data transmission i.e. the data forwarding in opposed direction between the key and lock is accmplished by means of semiconductor diodes operating mainly in the infrared range and constituting a transmissinon channel between light emitter and light receiver.

For economical reasons, the data transmission in both directions between key and lock system through the same channel is solved by suitable and programmed switching of the transmitter and receiver. Each electronic circuit, i.e. that of the key, just as that of the lock, comprises a single semiconducor diode only, where both circuit are switched over through a micro¬ processor to form a transmitter or receiver circuit, res- pectively, and offering the advantage of having identical circuit arrangement.

This arrangement exhibits the deficiency of being incapable of permitting bidirectional contactless transmission through a rotating shaft. Generally, by the infrared data transmission sys¬ tems different modulation methods are used, where the in¬ formation to be transmitted are, first, converted to a digital signal in order to minimize or eliminate the ef¬ fects of external interfering radiations. A method of that kind has been disclosed in Hungarian patent application No. 585/91 "Constructional arrangement for bidirectional wireless transmission of electric signals through optical means", where electric signals, especially acoustic signals, digital signals, measurement data or moving television pictures are bidirectionally transmitted through contactless optical paths, each device comprising a single-frequency oscillator, by the modulated frequency of which, on the one hand, the output of the optical transmitter is controlled and, on the other hand, this frequency is led to the mixing stage of the second device.

The frequency oscillator of the two devices has two different intermediate frequencies. The signal pro¬ vided by the optical receiver is mixed in the mixing stage to the modulated frequency signal of the frequency oscillator of the second device, then demodulating by means of a frequency modulator the sum frequency obtained through mixing the received frequency with the modulated oscillator frequency the received signal is extracted from the resultant signal.

Summary of the invention

The deficiency of this arrangement just as that of similar modulation methods lies in the considerable limitation by the modulation imposed by the modulation techniques on the field of application of infrared data transmission devices.

The aim of the invention is to eliminate the deficiencies of the solutions known so far by developing a circuitry and constructional arrangement for a wireless, contactless, bidirectional transmission of information between the various actuating and switching units of industrial process control equipments where said units are rotating with respect to each other around an axis by providing means for transmitting information without any kind of modulation, by way of analogue methods, permitting the use of any system of coding and without requiring establishment of mechanical contacts, rendering possible easy, quick eliable and durable accomplishment of the set aim.

The arrangement complying with the invention is based on the recognition that when two information trans¬ mitting and converting main units of expediently identical design - each consisting of a power supply unit, an optical receiver, an optical transmitter and a direction coupling unit - are arranged in the same axis of rotation, but opposite to and rotatably with respect to, each other, with the centre of each receiver unit placed in the same axis of rotation, but opposite to each other, and arranging each transmitter unit concentrically around the receiver pertaining to the other direction of transmission but permitting the light beam emitted by each transmitter to strike to opposite optical receiver only, and preventing from getting into the encircling re- ceiver located in the same side but belonging the other direction, further on either side a direction selecting unit is included in the setup serving for separating the flow of information of the two directions and for controlling the main unit, performing the task of information forwarding and converting moreover, and applying analogue signal transmission such a construction arrangement can be realized by means of which a bidirectional, analogue, wireless transmission of information can be realized without resorting to odula- tion, and permitting the use of any type of coding, without contacts for circuit closing and opening, through simple, quick, reliable and economical setup of long service life.

Thus, the present invention relates to a constructional arrangement and circuitry for bi- directional wireless transmission of information between the various units of industrial actuating and process control equipments across rotating/stationary shafts.

The circuit arrangement cuplying with the invention consists of two information forwarding and converting main units optionally of same design, each comprising a power supply unit, an optical receiver, an optical trans¬ mitter and a direction coupling unit.

The optical transmitter of one of the information transmitting and converting main units constitutes a transmission channel with the optical receiver of the other information transmitting and converting main unit, while the optical transmitter in the other information forwarding and converting main unit forms a transmission channel with the optical receiver of the main unit mentioned first.

Characteristic of the circuit arrangement complying with the invention is that the two information forwarding and converting main unit are accommodated in the same axis of rotation facing each other and in an angularly displaceable way, so rotating with respect to each other. The input of each directional coupling unit com¬ prised by each information forwarding and converting main unit is connected to the output of the corresponding optical transmitter, while the output of the latter is coupled to the bus system of the external unit.

The constructional arrangement complying with the invention comprises two information forwarding and converting main units, expediently of identical setup, consisting of two - power supply units, two optical receivers, two optical transmitters, and two directional coupling units.

The optical transmitter of one of the information forwarding and converting main units constitutes a trans- mission channel with the optical receiver of the other information forwarding and converting main unit, while the optical transmitter in the other information for¬ warding and converting main unit forms a transmission channel with the optical receiver of the main unit men- tioned first.

Characteristic of the constructional arrangement complying with the invention is that the centre of the sensor in one information forwarding and converting main unit and the centre of the sensor in the other informa- tion forwarding and converting main unit are arranged in the same axis of rotation facing each other and in an angularly displaceable way, such as being rotatable with respect to each other.

Concentrically around each optical receiver on optical transmitter is arranged so that the light beam emitted by the optical transmitter is permitted to act on the corresponding optical receiver facing it, preventing the beam from getting into the optical receiver arranged around it. Characteristic of the circuit arrangement is that - in an expedient embodiment - the directional coupling unit of each information forwarding and converting main unit is a hibrid transformer, one terminal of which is connected to one end of the terminating impedance, its other terminal to the other end of the terminating impedance, its third terminal to one end of the first resistor, its fourth terminal to one end of the second resistor, its fifth terminal to one end of the third resistor, finally the other ends of the first and second resistors joined together are earthed-

The ends of the terminating impedance constitue also the I/O terminals of the directional coupling unit, one end of the first resistor the output of the directional coupling unit, and the other end of the third resistor the input of the directional coupling unit. A further characterictic oof the circuit arrange¬ ment in another expedient embodiment of the direction coupling units of the two information forwarding main units, that it comprises a direction separating unit con- sisting of a bus matching circuit, a receiver timing unit, a transmitter timing unit and direction selecting unit, where the I/O terminal of the bus adjusting circuit forms the I/O terminal of the direction cupling unit, with its output being connected to the input of the receiver timing unit and its input to the output of the transmitter timing unit.

The I/O input-output of the receiver timing unit is connected to one of the I/O terminals of the direction selecting circuit, while the I/O of the transmitter timing unit to the other I/O terminal of said direction selecting unit, and the output of the receiver timing unit constitutes also the output of the direction timing unit, and the input of the transmitter unit is also the input of the direction coupling unit.- Characteristic feature of the setup of the direc¬ tion coupling unit incorporating a hibrid transformer is that the value of the first and third resistors are equal, whereas the resistance of the second resistor is half of the value of the first or third resistor, and the value of the terminationg impedance is equal to the impedance of the connected bus line.

Characteristic of the constructional arrangement is, further, that each optical transmitter unit has at least one, advantageously three light emitting diodes arranged optionally equally spaced along the periphery of a circle, with its centre lying in the axis of rotation, so as to make the light beam strike the centre of the sensor of the optical receiver unit arranged opposite to the corresponding transmitter. Each optical receiver unit is provided with a sensor consisting of a single light-sensor diode, the centre of which is arranged rotatably in the axis of rotation, opposite to the other rece _wer unit.

It is an expedient embodiment in which the optical transmitter units and the optical receiver units are operated in the infrared range.

A further characteristic feature of the circuitry and constructional arrangement complying with the inven¬ tion that each information transmission and converting main unit is accommodated in the axis of rotation and is mounted into a closed enclosure, protected against instrusion of external light beam.

The circuitry and constructional arrangement complying with the invention is described in detail with reference to the following drawings.

Figure 1 is the block diagram of the circuit arrangement complying with the invention, Figure 2 is the principle diagram of the construction arrangement complying with the invention, Figure 3 is an embodiment of the direction cupling unit, Figure 4 is a second embodiment of the direction coupling unit, Figure 5 shows the principle arrangement of the optical transmitter unit and optical receiver unit.

In Figure 1 the block diagram of the circuit arrangement complying with the invention is shown, having two information transmission and converting main units IA, IB, each consisting of a power supply unit IA, IB (preferably^" of identical design) _f of an optical receiver unit 2A, 2B, of an optical transmitter units 4A, 4B and of direction coupling unit 3A, 3B, respectively.

The optical transmitter unit 4A arranged in the in¬ formation transmitting and converting unit IA constitutes a transmission channel with the optical receiver unit 3B arranged in the other information transmitting and con¬ verting unit IB, whereas the optical transmission unit 4B arranged in the information forwarding and converting unit IB constitutes a transmission channel with the optical receiver unit 2A in said information forwarding and converting unit IA.

It is characteristic of the circuit arrangement that the two information transmitting and converting units IA, IB are arranged in the axis of rotation F, opposite and rotatably with respect to each other.

The inputs of the direction coupling units 3A, 3B separating the flows of information of the two directions and accommodated in the two information forwarding and converting unit IA, IB, are connected to the respective outputs of the optical receiver units 2A, 2B. Whereas their outputs are connected to the respective inputs of the optical transmitter 4A, 4B, finally their In-OutA and In-OutB input/output terminals are linked up with the buslines of the external unit. In Figure 2 the principle diagram of the construction arrangement complying with the invention is shown, having two information forwarding and converting main units IA, IB, each consisting of a power supply unit IA, IB (preferably of identical design) , of an optical receiver unit 2A, 2B, and a directional coupling unit 3A, 3B, respectively.

The optical transmission unit 4A arranged in the information forwarding and converting unit IA constitutes a transmission channel with the optical receiver unit 3B arranged in the other information forwarding and convert¬ ing unit IB, whereas the optical transmission unit 4B arranted in the information forwarding and converting unit IB constitutes a transmission channel with the optical receiver unit 2A in said information forwarding and converting unit IA. - li ¬

lt is characteristic of the construction arrange¬ ment that the centres of the sensors in the optical receiver unit 2A, 2B, respectively, mounted in one information transmitting and converting main unit IA and in the other information transmitting and converting main unit IB, are accommodated in the axis of rotation F, opposite and rotatably with Trespect to-each other.

Around each optical receiver unit 2A, 2B an optical transmitter unit 4A, 4B is concentrically arranged so that the light ray emitted by said optical transmitter units 4A, 4B gets only to the respective opposite optical receiver unit 2B, 2A, and is prevented from hitting the optical receiver unit 2A, 2B, arranged beside it.

In Figure 3 an expedient implementation of the direction coupling unit 3A, 3B is illustrated, where the first outlet 311 of the hybrid transformer 31 is connect¬ ed to one end of terminating impedance Z, its second out¬ let 312 is connected to the other end of terminating impedance Z, its third outlet 311 is coupled to one end of the first resistor Rl, its fourth outlet 314 to one end of the second resistor R2, its fifth outlet 315 to one end of the third resistor R3, while the connected other ends of first resistor Rl and second resistor R2 are earthed. The ends of the terminating impedance Z constitute, at the same time, the input-output terminals of the direction coupling units 3A, 3B, the third outlet 313 of the hybrid transformer 31 forms the output of direction coupling unit 3A, 3B whereas the other end of the third resistor R3 constitutes the input of the direction coupling unit 3A, 3B.

Characteristic of the realization of the direction coupling unit 3A, 3B with hybrid transformer 31 is that the values of first Resistor Rl and third resistor are equal, while the value of the second resistor R2 is half of the value of the first resistor Rl and of the third resistor R3, and the value of the terminating Z is equal to the impedance of the connected busline.

In Figure 4 another expedient embodiment of the direction coupling unit is shown, where the direction coupling unit 3A, 3B is a direction separating unit con¬ sisting of a bus matching circuit 32, a receiver timer 33, a transmitter timer 34 and a circuit selecting circuit 35. The input-output 321 of the bus matching unit 32 is, at the same time, the I/O of the direction coupling unit 3A, 3B, with its output 30 2 connected to the input of receiver timer 33, and its I/O to the output 341 of transmitter timer 34. The I/O 342 of transmitter timer 34 is connected to the other I/O 352 of the direction separating unit 35, the output 332 of the receiver timer forming at the same time the output of direction coupling unit 34, 35 whereas the input 343 of transmission timer constitutes, at the same time, the I/O of directional coupling unit 34, 38.

Figure 5 shows the principle arrangement of the optical transmitter unit 4A, 4B and of the optical receiver unit, characteristic of which beinng, that each optical transmitter unit comprises at least one, but pre- ferably three LEDs 41, 42, 43 advantageous spaced at equal angles apart along the circumference of a circle of radiant with its centre lying in the centre of the axis of rotation, arranged so that the axis of the light beam hits the centre of the sensor of optical receiver unit 24, 28 located opposite.

Each optical receiver unit 2A, 2B comprises a single light-sensor diode 21, the centre of which is arranged rotatably, in the axis of rotation F opposite to the other similer diode. Operation of the arrangement complying with the in- vention is as follows:

After having arranged in the axis of rotation F the information transmitting converting main units IA and IB of identical design, facing each other, the information carrying signal arriving from the busline gets to the I/O terminals of one of the direction coupling units 3A.

This signal is separated by the direction coupling unit 3A and passed to the input of optical transmitter unit 4A. The high-speed signal is sent ay the optical trans¬ mitter unit 4A by means of a light beam toward the opti¬ cal receiver unit 2B accommodated in the other informa¬ tion forwarding and converting main unit IB capable of rotating with respect to it so that the light beam is directed from several sides onto the centre of the opti¬ cal receiver unit arranged 2B o: site to it. Since the three LEDs 41, 42, 43 are locate -. equal distances from the axle of rotation F, the li_a..ε beam emitted by the LEDs will always precisely strike the centre of the sensor of the optical receiver unit 2B.

The optical receiver unit 2B is sensing the in¬ cident light rays and converts them into an electric signal.

After amplification the converted electric sit nal gets from the output of optical receiver unit 2B to the input of the other direction coupling unit 3B.

This signal is matched by the direction coupling unit 3B to the I/O of In-Out B and, in this way, its drive with an output corresponding to the busline of the other external unit can be ensured.

In the case of signals carrying the information arriving from the ther external unit the operation takes place in a similar way.

In the arrangement complying with the invention the setup of the direction coupling unit 3A, 3B is of determining importance.

Namely, in industrial actuating and process-control equipment, information is represented by electric signals flowing in the pair of conductors. However, for the transmission of signals through a pair of conductors and for their amplification a single amplifier is not sufficient. ^{. ~} - _

Either direction has to be amplified independently and it has to be ensured that - on the one hand - the signal arriving from a direction be fed to the input of the respective amplifier and be forwarded in the respec¬ tive direction and - on the other hand - the output signal of the amplifier has to be prevented from gettinng on the inpuut of the other amplifier. A further requirement is to terminate the connect¬ ing busline in a reflection-free way. These requirements can be satisfied by properly dimensioning the direction coupling unit 3A, 3B.

In an advantageous embodiment of the arrangement complying with the invention the direction coupling unit 3A, 3B is a hybrid transformer 31 comprising three wind¬ ings, where the first winding is conncted to the two ends of the terminating impedance Z, the second winding is connected across one end of the first resistor Rl and one end of the second resistor R2, fnally the third winding is linked up with one end of the second resistor R2 and with one end of the third resistor R3, and the number of turns of the second and third windings is equal.

Each optical transmitter unit 4A, 4B consists of a transistorized amplifier and a driving stage connected to the input of the respective direction coupling unit 3A, 3, to which three LEDs are advantageously coupled.

Each optical receiver unit 2A, 2B contains a light- sensor diode 21, to the output of which a wide-band high- gain amplifier stage is connected. At the output of each directional coupling unit 3A, 3B a signal appears only in the case, when a signal arrives from output of the respective I/O terminal In-Out A, In-Out B of said directioon coupling unit. The signal arriving to the input of the direction coupling unit 3A, 3B does not get to the output of the output Out of said direction coupling unit 3A, 3B, it is only forarded toward the I/O terminal In-Out.

In this way, the two-direction signal arriving to the I/O terminal of In-Out A, In-Out B is separated according to its direction and is passed toward the input In and output Out of the respective direction coupling unit 3A, 3B, ensuring thereby that the transmission of information can take place in both directions. In another advantageous embodiment of the arrange¬ ment complying with the invention each direction coupling unit 3A, 3B is a direction separating unit conisting of a bus matching circuit 32, a receiver timer 33, a trans¬ mitter timer 34 and a direction selecting circuit 355, the operation of which is as follows.

The direction selecting unit 35 controls through its other I/O terminal the I/O 342 of the transmitter timer 34, i the consequence of which the bus matching circuit 32 gets in rceive state, and remains in that state until transmission takes place.

In the case of transmission, this receive state is suspended by the receiver timer 33 and, in this case, forwarding of information takes place through output ter¬ minal 332 of the receiver timer 33 to the output terminal out of the direction coupling unit 3A, 3B.

After the elapse of the adjusted time the original state is restored.

The circuits are fed from 24-volt supply units IA, IB. The aim set has been accomplished by the arrange- ment complying with the invention because by means of it transmission of information can be accomplished bi¬ directional between different units of industrial actuate- ing and process control equipment facing and rotating with respect to each other, without modulation, by means of analogue method, with arbitrary coding, without mechanical contacts quickly, reliably, -ensuring long service life and economically.

Advantage of the solution complying with the inven- tion is its suitability for continuous 24-hour operation, the accomplished transmission of information is of long service life, requires no maintenance, because it does not contain moving parts.

Claims

1. Circuit arrangement for bi-directional wireless transmission of information, through rotating/stationary axes between different units of industrial,actuating and process control equipment said arrangement incorporating two information forwarding, transmitting and converting main units (IA, IB) preferably of identical design, each consisting of a power supply unit (IA, IB), an optical receiver unit (2A, 2B) a direction coupling unit (3A, 3B) , and an optical transmitter unit (4A, 4B) , where the optical transmitter unit (4A) located in one of the two information frwarding and converting main units (i.e. IA) constitutes a transmission channel with the optical re- ceiver unit (2B) located in the other information for¬ warding and converting main unit (IB) while the optical transmitter unit (4B) located in the other information forwarding and converting main unit (IB) constitutes a transmission channel with the optical receiver unit (2A) located in said one of the two information forwarding and converting main units (i.e. IA) c h a r a c t e r i z ¬ e d b y the two information forwarding and converting units (IA, IB) being arranged in the axis of rotation (F) and rotatably with respect to each other, and the input of the direction coupling unit (3A, 3B) comprised by the two information forwarding and converting main units (IA, IB) and separated the bi-directional flow of information being connected to the output of the optical receiver unit (2A, 2B) , and the output of said direction coupling unit (3A, 3B) being connected to the input of the optical transmitter unit (4A,.4B) and its I&O (In-out A, In-Out B) being connected to the buslines of an external unit.

2. Construction arrangement for bi-directional wireless transmission of information, through rotating stationary axes between different units of industrial actuating and process control equipment said arrangement incorporatng two information forwarding and converting main units (IA, IB) preferably of identical desing, each consisting of a power supply unit (IA, IB) , an optical receiver unit (2A, 2B) a direction coupling unit (3A, 3B) , and an optiral transmitter unit (4A, 4B) , where the optical transmitter^" unit (4A) ^"Tocafed in^"one^" of^"the in¬ formation forwarding and converting main units (i.e. IA) constitutes a transmission channel with the optical receiver unit (2B) located in the other information for¬ warding and converting main unit (IB) , while the optical transmitter unit (4B) located in the other information forwarding and converting main unit (IB) constitutes a transmission channel with the optical receiver unit (2A) located in sadi one of the two information forwarding and converting main units (i.e. IA) c h a r a c t e r i z ¬ e d b y the two information forwarding and converting units (IA, IB) characterized by the sensor of the optical receiver unit (2A) located in one of the two information forwarding and converting main units (i.e. IA) and the sensor of the optical receiver unit (2B) located in the other information forwarding and converting main unit (IB) being arranged placed with their centres facing each other and rotatably in the axis of rotation, and around each optical receiver unit (2A, 2B) an optical trans¬ mitter unit (4A, 4B) is concentrically accommodated, so that the light beam emitted by each optical transmitter unit (4A, 4B) can only reach the respective optical receiver unit (2B, 2A) arranged to opposite to it, and the beam is prevented from itting the optical receiver unit (2A, 2B) arranged beside it.

3. Circuit arrangement as claimed in Claim 1, c h a r a c t e r i z e d b y the direction coupling unit (3A, 3B) in each information forwarding and coupling unit (IA, IB) is a hybrid transformer (31) , connected with its first outlet (311) to one end of the terminating impedance (Z) , with its second outlet (312) to the other end of said terminating impedance (Z) , with its third outlet to one end of the first resistor (Rl) , with its fourth outlet (314) to one end of the second resistoor (R2) , with its fifths outlet to one end of the third resistor (R3) , and the other ends of said first and second resistors (Rl, R2) are connected to the earth, and the ends of said terminating impedance (Z) constitute, impedance (Z) at the same time, the I/O (In-Out) of the direction coupling unit (3A, 3B) , the first outlet (311) of the hybrid transformer (31) constitutes the output terminal (Out) of said direction coupling unit (3A, 3B) , and the other end of the third resistor (R3) is linked up with the input (In) terminal of said direction coupling unit (3A, 3B) .

4. Circuit arrangement as claimed in Claim 1, where each of the two direction coupling units (3A, 3B) of the information forwarding and converting main units (IA, IB) is direction separating units consisting of a bus matching circuit (32) , a receiver timer (33) and a trans¬ mitter timer (34) , where the I/O terminal of said bus matching circuit (32) is at the same time, the I/O (In- Out) terminal of the direction coupling unit (3A, 3B) , its output (22) being connected to the input (331) of receiver timer (33) , its input (323) to the output (341) to transmitter timer (34) the I/O (333) of the receiver timer (33) is connected to one I/O (351) of the direction selecting circuit (35), and the I/O (342) of the trans- mitter timer (34) is linked up with the other I/O (352) of the direction selecting circuit (35) , the output (332) of the receiver timer (33) constituting, at the same time, the output (Out) of the direction coupling unit (3A, 3B) , while the input (343) of transmitter timer (34) is at the same time, the input (In) of the direction coupling unit (3A, 3B) .

5. Circuit arrangement as claimed in Claim 3, c h a r a c t e r i z e d i n that in the direction coupling units (3A, 3B) the values of the first and third resistors (Rl, R3) being equal, whereas the value of the second resistor (R2) is half of the value of first resistor (Rl) and half of the value of third resistor (R3) , and the value of the terminating impedance (Z) is equal to the impedance of the connected busline.

6. Constructional arrangement as claimed in Claim 2, characterized by the optical transmitter units (4A, 4B) and the optical receiver units (2A, 2B) being operated in the infrared band, and each optical trans¬ mitter unit being (4A, 4B) provided with at least one, but advantageously with three diodes (41, 42, 43) ex¬ pediently arranged uniformly spaced apart along the periphery of a circle with its centre located in the centre of the axis of rotation (F) , so that the axis of the light beam hits the centre of the sensor of the op- tical receiver unit (2A, 2B) arranged opposite to the transmitter, each optical receiver unit (2A, 2B) being provided with a single light sensor diode having its centre located in the axis of rotation (F) rotatably with respect to the transmitter.

7. Circuitry and constructional arrangement as claimed in Claims 1 to 6, c h a r a c t e r i z e d b y the information forwarding and converting main units (IA, IB) being mounted in the totally enclosed housings axis of rotation (F) , is placed in enclosures, totally preventing light beams from intrusion.