Electrical system for controlling at least one gate or door or similar element of the type moved electrically

The invention relates to an electric system for controlling at least one gate or door or the like electrically movable by means of at least one suitable electric motor.

In electrical systems for controlling the entrance gate and / or garage door of a residential house, various units are usually placed to form a system where it is necessary to connect them by electric wires.

In a residential house, they can be installed, for example: motor for one gate leaf, motor for the second gate leaf, garage door motor, radio receiver for receiving gate and door movement requests from remote controls, key-operated selectors and / or command key blocks for gate or door actuation, various systems photoelectric security (such a photoelectric system is composed of a transmitter and a receiver) and light and acoustic devices to signal the movement of the gate and door.

Until recently, the number of devices installed was relatively small (four or five) and these devices, for simplicity, were placed very close to each other, for example next to a gate.

Recently, international security regulations on the one hand and user requirements on the other hand have resulted in a significant increase in installed devices (often ten or similar or even more) and prevented them from being placed close together, and this trend continues.

The specific sector of garage doors and gates for commercial and industrial premises is regulated at European level by the CEN standard prEN 13241.

Installed devices of this kind are electrically connected to the electric control system, and more precisely usually these devices are connected directly and locally to peripherals of the electric control system, which devices are connected directly, by means of electric wires, to the central unit of the electric control system, "heart". "System.

In these systems, therefore, a lot of electrical wiring is required.

Due to the type of application, there are many such electrical cables and they are often very long (many tens of meters and in some cases even hundreds of meters), so their cost is usually quite high, moreover, the cost of their installation (usually underground, preferably in protective tubes).

Again, due to the nature of the application, these electric cables are placed outside the house, underground and in a distributed manner (as there are essentially no space restrictions) and therefore the danger of cutting one of them, for example when working in the garden, is quite possible.

Moreover, the many electrical wiring associated with the various devices to be installed results in a complex electrical system and easily introduces an increase in connection errors during installation (both regarding the polarity of the wires and regarding the cooperation between the wires and connectors), even on the part of qualified personnel.

EP 0624541 describes a door control unit, in particular for elevator doors and / or other sliding doors, which meets a high safety standard and improves the ease of operation by an increased degree of automation. The door control unit includes a programmable microcontroller to which programmable control units and operating units that are at a higher level than the sensor elements may be connected. The microcontroller is efficiently coupled to the drive motor of the door or more doors and is characterized by a switching device with a selection of at least two operating modes.

The solution to the above-mentioned problems, which is interesting from a practical point of view, must be simple (both in terms of connections and in terms of the device), relatively inexpensive and must not require any other special knowledge or training on the part of the installation personnel system.

The object of the present invention is to provide a solution to the above-mentioned problems.

This object is substantially achieved by the electric control system of the present invention.

The electrical system according to the invention is characterized in that each peripheral device comprises a polarity adapter circuit having two inputs and two outputs, the two inputs being connected to its two terminals, respectively, and a voltage detection circuit whose inputs

The PL 213 980 B1 are connected correspondingly to the outputs of the polarity adapter circuit. The central control unit comprises a current sensing system, the input of which is connected to one of the two terminals of the central control unit, the at least one peripheral being electrically connected to a safety device for gates or doors.

Preferably, a central control unit connected to at least one peripheral device via a network bus comprises a voltage generator circuit having an output connected to one of the two terminals of the central control unit, and a modulation circuit connected between said output and said terminal.

Preferably, at least one peripheral device is electrically connected to the device for requesting movement of the gate or door.

Preferably, at least one peripheral device is electrically connected to the electric motor.

Preferably, each of the peripheral devices includes a power circuit, the inputs of which are connected to the outputs of the polarity adapter circuit respectively.

Preferably, each of the peripheral devices includes a load circuit whose outputs are connected to the outputs of the polarity adapter circuit respectively.

Preferably, each of the peripheral devices, at least one of which is connected to the security device, comprises a memory unit storing its own device identification code.

Preferably, a security device consisting of a transmitting section and a receiving section is connected to peripheral devices, one peripheral device being electrically connected to the transmitting section of the security device and / or another peripheral device being electrically connected to the receiving section of said security device.

Preferably, a security device consisting of a transmitting section and a receiving section is connected to peripheral devices, one peripheral device being electrically connected to the transmitting section of the security device and / or another peripheral device being electrically connected to the receiving section of said security device.

Preferably, the security device is a photoelectric system or an edge sensing system or a frosted presence detector or a radar presence detector.

The basic idea of ​​the present invention is to use an electrical network consisting of only two electrical conductors for the entire system that is adapted to distribute both DC power and digital information, and to limit the connections between system devices and the system network.

The invention will become clearer from the following description, taken together with the accompanying drawings, in which:

Fig. 1 is a diagram of a rather complicated system according to the present invention, Fig. 2 - a conceptual diagram of a system according to the present invention, Fig. 3 - a block diagram of a central unit of a system according to the present invention, Fig. 4 - a block diagram of a system peripheral according to the present invention, Fig. 5 is a schematic diagram of the central unit of the system according to the present invention, divided into three parts (Figs. 5-A, Figs. 5-B, Figs. 5-C), 6 - an electrical diagram of a system peripheral according to the present invention, Fig. 7 - an electrical diagram of another system peripheral according to the present invention, and Fig. 8 - an arrangement of two photoelectric circuits and a connection diagram with the individual peripherals of the system according to the present invention.

With reference (not limiting) to Fig. 2, the electric control system of the present invention is intended to control at least one gate or door or the like (hereinafter, reference will often be made to a gate for simplicity of description) of the sliding type by means of at least one suitable motor. electric, and the system includes:

a) NTWRK electric network consisting of two electric wires adapted to distribute power and digital information,

b) a central control unit UC having two terminals T1, T2 adapted to be connected individually but directly to two wires of the NTWRK network for the purpose of transmitting DC power and transmitting and receiving digital information,

PL 213 980 B1

c) a plurality of peripheral devices UP, each having two terminals T1, T2 adapted to be connected individually but directly to two lines of the NTWRK network for receiving DC power and receiving and / or transmitting digital information.

Fig. 2 conceptually shows N peripheral devices UP designated UP-1, UP-2, UP-3 ... UP-N.

The NTWRK network of the present invention, with two conductors, may include branches as seen in the diagram of Fig. 1, and also in the complex arrangement of Fig. 1, there are only two electrical conductors conceptually. twin wire sections that are properly connected to each other.

As can be seen from the diagram in Fig. 1, the wiring is simple, the number of wires is minimal (both for power supply and information) and the wire length is minimal if the installation is done correctly (branches limited to the minimum necessary).

The devices are connected to each other (in parallel) in the NTWRK network and without the need for polarity, so it is not possible to introduce an error when connecting.

Power can be obtained in the form of direct current directly from the NTWRK network. This power supply is mainly intended for the peripheral devices that make up the system and which can therefore be extremely simplified from a power point of view. These peripheral devices may then supply power in turn to the devices to which they are connected and which may therefore be simplified from a power point of view.

The circuit that produces power for the NTWRK network (and therefore for the peripherals and, if necessary, for devices connected thereto) is generally housed inside the enclosure which contains the CPU of the UC.

Depending on the type of device to which the peripheral device is connected, the latter may only need to receive digital information (such as conceptually e.g. a light signaling device) to only transmit digital information (such as conceptually e.g. a security device) and both receive and receive transmit digital information (as will be explained below).

Such an electrical control system must be connected to at least three essential devices: an electric motor to move the gate, a device for inputting requests to move the gate (e.g. a key operated selector, a command keypad, a remote control receiver, etc.) and a safety device (e.g. photoelectric, edge sensing system, frosted appearance detector, radar presence detector etc.).

Depending on the functions performed by the central unit UC, there are three possible solutions to the present invention.

According to a first embodiment, the system comprises at least three peripheral devices each having terminals adapted to be connected individually but directly to two network conductors for receiving DC power and receiving and / or transmitting digital information, one of the peripheral devices being adapted to electric connection to the electric motor to control its operation, wherein one of the peripheral devices is arranged to be electrically connected to a gate or door sliding request device or the like, wherein one of the peripheral devices is adapted to be electrically connected to a gate or door safety device or the like.

In other words, according to this first embodiment, three principal devices are electrically connected to three different peripheral devices.

According to a second embodiment, the system comprises at least two peripheral devices each having two terminals adapted to be connected individually but directly to two network conductors for receiving DC power and receiving and / or transmitting digital information. wherein the central unit is arranged to be electrically connected to the electric motor to control its operation and / or to a gate or door sliding request device or the like and / or to a gate or door safety device or the like, wherein a peripheral device is adapted to be electrically connected to the electric motor to control its operation and / or to a gate or door sliding request device or the like and / or to a safety device for gates or doors or the like, where the other peripheral device is adapted to electric connection to the electric motor to control its operation

And / or to a device for inputting a request to move a gate or door or the like and / or a safety device for gates or doors or the like.

In other words, according to this second embodiment, one of the essential devices is electrically connected directly to the central unit, while the other two essential devices are electrically connected to two different peripheral devices.

According to a third embodiment, the system comprises at least one peripheral device having two terminals adapted to be connected individually but directly to two network conductors for receiving DC power and receiving and / or transmitting digital information, the central unit being adapted to be electrically connected to an electric motor. to control its operation, and / or a gate or door sliding request device or the like, and / or a safety device for gates or doors or the like, where the peripheral device is adapted to be electrically connected to the electric motor to control its operation, and / or to the device requesting the sliding of a gate or door or the like, and / or a safety device for gates or doors or the like.

In other words, according to this third embodiment, two of the principal devices are electrically connected directly to the central unit, and the third principal devices are electrically connected to the peripheral.

In all three embodiments, it is possible to provide many other peripherals electrically connected to additional devices, for example other motors, other input devices, other safety devices, signaling devices, etc.

In all three embodiments, it is also possible to ensure that some additional devices are electrically connected directly to the central unit.

The diagram in Fig. 1 shows a system according to the present invention which is quite complex. The area A1 of the garden where the entrance gate is located includes peripheral U1 for the receiver of the first photoelectric circuit, peripheral U2 for the signaling device, peripheral U3 for the receiver of the second photoelectric circuit, peripheral U4 for the motor to actuate the right door leaf, peripheral U5 for the engine that activates the left door leaf, peripheral U6 for the transmitter of the second photoelectric system, peripheral U7 for the transmitter of the first photoelectric system, peripheral U8 for the key operated selector, and the apartment house area A2 contains only the central unit UC, in addition, a peripheral U9 is provided for the remote control receiver in a place where it is easy to pick up remote control signals, and the NTWRK network with twin conductors electrically connects all these separate devices in an optimal way and of course also other peripherals for other devices could be connected to the NTWRK network, which is indicated by a dashed line.

The basic idea of ​​the present invention, namely the use of an electrical network consisting of only two electrical conductors for the entire system, which is adapted to allow distribution of both DC power and digital information, and not imposing any restrictions on the connection between system devices and the system network, requires the use of proper layout in the UC control unit and UP peripherals.

Referring to Fig. 3, a possible preferred structure of a UC that may be used in a system according to the present invention will be described below.

This CPU UC includes a voltage generator GT, the output of which is connected to one of the CPU's two pins T1, T2 (T2 pins in this example) and adapted to produce a DC power supply (e.g. +12 volts), and a modulation MOD enabled between this output and this pin and adapted to modulate the DC supply by digital information.

The simplest modulation performed in this case is on / off modulation: for example, when the UC CPU transmits the digital value "1" = "high", the potential difference between the two wires of the NTWRK network will be approximately +12 volts and when the UC CPU transmits a digital value of "0" = "low", the potential difference between the two network conductors will be approximately 0 volts.

The UC CPU may further comprise a RC current detector circuit whose input is connected to the other of the CPU's two pins T1, T2 (T1 pins in this example) and adapted to extract digital information from the input current, and since the RC circuit will be

The difference in potentials between the two conductors of the NTWRK network was influenced by the potential difference, the voltage drop caused by it must be small.

Referring to Fig. 4, a possible preferred peripheral structure UP that can be used in the system according to the present invention will be described below.

This peripheral UP includes a polarity adapter AP circuit having two inputs and two outputs, and these two inputs are connected to the two terminals T1, T2 of the peripheral device respectively, so there will be electrical signals at the outputs of the AP circuit having a predetermined polarity, regardless of polarity electrical signals at terminals T1, T2.

The UP peripheral may further include an AL power supply circuit, the inputs of which are connected to the outputs of the AP polarity adapter circuit, and this arrangement may be quite simple since it is already possible to obtain a DC voltage (e.g. +12 volts) with the correct polarity from the NTWRK network in conjunction with the AP, it therefore only remains to eliminate the effects of transmission by the UC and any interference.

The peripheral UP may further comprise a voltage RT detection circuit, the inputs of which are connected to the outputs of the polarity adapter circuit AP, respectively, and adapted to extract digital information from the voltage at the inputs. If the central unit UC modulates the on / off voltage in the NTWRK network, this signal is essentially ready to be sampled and distinguished by the peripheral UP; for example, if the sample has a voltage value greater than +8 volts it will correspond to a digital value of "1" = "high" and if the sample has a voltage value less than +4 volts it will correspond to a digital value of "0" = "low".

The peripheral device UP may further comprise a load circuit CC, the inputs of which are connected to the outputs of the polarity adapter circuit AP and adapted to load it according to digital information. A simple way to do this is to use an on / off solution for this case as well: for example, when the UC peripheral wants to transmit the digital value "1" = "high", the CC supplies the network (using the AP) a load that causes additional current flow in the NTWRK network and when the UC peripheral wants to transmit the digital value " 0 "=" low ", the CC circuit does not supply any load to the grid and therefore causes no additional current flow in the NTWRK grid. These current differences are detected by the RC of the UC CPU.

All UP peripherals are connected in parallel to the NTWRK network, so it is necessary to take into account the current consumed by all connected AL, RT, CC when designing the UC voltage generator GT.

According to a preferred embodiment of the present invention, the transmission of digital information both as a voltage from the CPU UC to the peripheral UP and as a current from the peripheral UP to the CPU UC uses a 1 / 3-2 / 3 PWM (Pulse Width Modulation) solution. and each bit has a predetermined duration considered individually: if a pulse is less than one third of the predetermined duration, the bit is logical for example "0", while if a pulse is more than two-thirds of the predetermined duration, the bit is logical for example "1".

For the sake of completeness of the description, some detailed electrical diagrams of specific embodiments of parts of the system according to the present invention have been appended to the present description.

Fig. 5 shows an electrical diagram of the central unit according to the present invention, divided into three parts: Figs. 5-A, Fig. 5-B and Fig. 5-C. Fig. 5-A shows part of the CPU interface with the NTWRK network, Fig. 5-B shows the radio section of the CPU's remote control receiver with the NTWRK network, Fig. 5-C shows the rest of the CPU.

Fig. 6 shows an electrical diagram of a peripheral device adapted to be connected to the receiver of the photoelectric system and to the NTWRK network.

Fig. 7 shows an electrical diagram of a peripheral device adapted to be connected to the transmitter of the photoelectric system and to the NTWRK network.

Aspects of the present invention that are more closely related to the operation of the system will be described below.

In order to be properly and efficiently adapted to the exchange of digital information, it is preferred that each of the peripheral devices comprises memory means adapted to store its own device identification code which can be used as an address. These memory elements can be standard semiconductor memories (EPROM, EEPROM, FLASH or RAM) or, more simply, microswitches, or even more simply, switches, and the choice depends on

From both cost and installation criteria: in fact, the device identification code can be determined either during manufacture or during installation and can be constant or variable.

In the specific examples of Fig. 6 and Fig. 7, for example, the code is defined by one or more connectors and by four contacts placed in the corners of the square, if there are two connectors, both can be connected horizontally, both vertically, or one horizontally and one vertically. in four different ways, and if there is only one connector, it can be connected horizontally on the top, horizontally on the bottom, vertically on the right and vertically on the left.

For safety devices consisting of a transmitting section and a receiving section (which are usually spaced apart), e.g. photoelectric systems, two associated peripheral devices may be provided, adapted to be connected to the transmitting section and receiving section, respectively, and identified. by the same device identification code; in this way, if the control unit needs to transmit digital information to the photoelectric system (e.g. a state read request), a single transmission to the same address can be made.

A particularly effective and efficient solution for establishing communication between the central unit and peripheral devices consists in exchanging digital information packets using the "master-slave" technique, with the control unit acting as a "master" and the peripheral device acting as a "slave, in other words, the peripheral waits for a request from the central unit before transmitting the digital information packet.

Depending on the type of device connected to the peripheral device, when the peripheral device receives the packet from the CPU, it might not be strictly necessary to transmit the response packet via the peripheral device to the CPU; this typically occurs when the CPU transmits a command to the peripheral to start an engine or signaling device. However, it is preferable for the CPU that the response should be transmitted in all cases; in fact, for example, this response packet could contain information that the command was performed satisfactorily, and failure to receive this acknowledgment could cause retry.

In the master-slave technique, in order to provide commissioned communication between the central unit and a peripheral device, the central unit may preferably be adapted to transmit packets over the network at a fixed and predetermined rate, for example every 10 or 20 or 30 ms. .

In this case it is necessary to decide to whom the packets should be addressed; many criteria can be used, on the one hand, it is necessary to query the peripheral devices connected to the input devices with a certain frequency to enable any opening or closing requests, and on the other hand, proper control by the central unit (by means of peripheral devices) of the motor is needed and signaling devices, on the other hand, the central unit must interrogate with a certain frequency, while the engine is running, peripherals attached to the safety devices to cover the hazardous situations. Other considerations that may influence the choice of destination are presented below.

One or more peripherals may be adapted to extract the timing information from the constant packet rate transmission by the control unit; in fact, the transmission at a constant rate, in addition to providing the requested communication in the system, results in the distribution of unique timing information which is important for the entire network and on the basis of which synchronization may be performed if necessary.

It is expedient that the length of packets that are sent in the NTWRK network should be the same, in particular for packets sent from peripheral devices, and the structure of packets sent from the central unit may differ, if necessary, from the structure of packets sent from peripheral devices . Depending on the type of application, the structure of a digital information packet can in any case be extremely simple: a packet from a central unit can consist, for example, essentially of a combination of a peripheral code and a sequence of one or two or three bits that identify the command, and the packet from the peripheral devices for example, it may consist essentially of only a short sequence of data bits.

In order to significantly facilitate the installation of the system, the central unit can be adapted to perform, during the start-up or restart of the system, the identification of all

Due to the fact that active peripheral devices are connected to the network by means of packet exchange, the central unit autonomously determines the structure of the system.

In order to obtain a diagnostic procedure for the system, the central unit may be arranged to perform, repeatedly while the system is running, identifying all active peripherals connected to the network by means of packet exchange, and by comparing the list of active peripherals after the system has booted through the list of are active at a certain point in time, it is possible to obtain, after any proper verification, identifying defective or isolated peripheral devices, and in conjunction with a defective or isolated peripheral device, the peripheral device may decide to take appropriate measures (lamp lighting, system shutdown, alarm activation).

By properly selecting the device identification codes and the digital information packet structure (and of course the software loaded into the central control unit), it is possible to program the central unit with a programming device connected to the particular peripheral identified by an identification reserved code.

The present invention has been described so far in relation to home entrance gates and garage doors, but it is obvious that it is applicable and its protection thus extends to other similar locking elements, in particular other types of gates and doors; for example problems similar to those mentioned arise in the sector of road barriers and shutters in factories and shops.

An important aspect of the electric control system of the closure element that is electrically displaced is the reliability regarding the exchange of digital information; in some cases, replacement problems could cause undesirable phenomena (e.g. gate opening failure), while in other cases they could also cause serious accidents (e.g. a person getting caught between the gate leaves).

Information exchange errors are mainly related to disturbances in the system network which overlap with the electrical data signals produced on the network itself; errors may also be related to the overlapping of two transmissions performed by two different system devices.

In a system as described above, the first measure that can be used to improve the reliability of the data exchange, in particular to prevent overlapping errors, is to use the master-slave technique (already mentioned above), in fact the device peripheral transmits only on request from the central processing unit and the central processing unit only queries one peripheral device at a time.

In a system as described above, a second measure that can be used to improve the reliability of the data exchange, in particular to prevent errors related to interference, is to provide a procedure whereby after the transmission of digital information, in particular a packet, from source to the recipient, the recipient always delivers a response to the source in the form of digital information, in particular a packet, e.g. depending on the type of recipient, and the response may be a simple acknowledgment of receipt or an actual data item.

When the master-slave technique is used, the source is always the central unit of the system and the recipient of the peripheral devices of the system.

In a system as described above, a third measure that can be used to improve the reliability of the data exchange, in particular to prevent interference errors, is to ensure that certain digital information is transmitted twice from the same source to the same source. to the receiver itself, typically this information could be transmitted sequentially, in which case the receiver may consider the transmission valid only if the received digital information matches. In the case of packet transmission, the source could for example transmit the same packet twice in succession to the same recipient. It is obvious that this solution doubles the amount of data traffic on the network.

It is also possible for this duplicate transmission performed on the basis of a predetermined criterion, for example a choice which is a good compromise in terms of reliability and traffic, which is repeating transmission only to specific recipients; for example, an undesirable ignition of a light signaling device (i.e. without an actual command from the system) is an event that may be acceptable, while an undesirable closure of a gate (i.e. without an actual command from the system) is an event that is unacceptable due to the risk of injury or damage, it is therefore possible to divide, for example,

Peripheral devices for "high risk" devices and "low risk" devices, and duplicating only information that is transmitted to "high risk" devices.

In the case where the "master-slave" technique is used, it may be advantageous to ensure that only the central unit of the system, namely the "master," automatically transmits digital information twice, in particular packets intended for peripheral devices, namely "slave" devices. peripheral, if the central unit considers, on the basis of a predetermined criterion, that it is necessary to double the transmission, it will double the query, which could be the case of security devices whose transmitted data is of particular importance to the CPU and to the system.

A measure that is quite widely used to determine errors in the transmission of digital information is the parity bit, well known in the telecommunications sector, and moreover, the presence of rather complicated codes that allow detection and / or correction of one or more transmission errors.

Even if a master-slave technique is used, it is not possible to completely eliminate the danger that two peripheral devices may transmit CPU data at the same time and therefore generate errors due to the overlapping of two transmission operations, which could occur in e.g. case when, due to interference, two different peripheral devices could use the same digital information packet as intended for them.

In a system as described above, a fourth measure that can be used to improve the reliability of the data exchange, in particular to detect overlap errors, is the complexity of the structure of the digital information packet: in this case, the packet comprises a data portion and a control portion. and it is highly unlikely that when receiving digital information obtained from the overlapping of two packets, the data part and the control part will correspond.

If the master-slave technique is used, arbitrary overlap usually occurs when the query is answered by the "master" element, so it may be advantageous to decide that the structure of the packet transmitted by the "master" element should contain only data (address and command) plus a bit. parity and that the structure of the packet transmitted by the slave should contain both a data part and a check part without the parity bit. The control part could be provided in many different ways and a simple and effective solution will be described below.

The data part and the packet control part are selected of the same length (e.g. 4 or 8 bits), and the source that wants to send digital information over the network takes a digital sequence of data, takes a random digital sequence of the same length as the data (generated still in a known manner in the source), produces a digital check sequence with an OR operation excluding between the data sequence and the random sequence, inserts a data sequence and check sequence into the packet and transmits the packet over the network, and the receiver receives the packet and performs the reverse operation (which is again an exclusive OR operation), extracting a digital data sequence transmitted in no overlap, and if the overlap occurs with a packet transmitted by others device, the recipient's digital sequence will not correspond to the transmitted digital data sequence, but the receiver will not be able to detect it, and if the source retransmits the digital data sequence, the random digital sequence that is used will be different, so that the second transmitted packet is different, the receiver receives a second packet different from the first packet not covered or not subjected to a different coverage, and if there has been no overlap during both transmissions, the receiver extracts the same digital sequence; if there was an overlap during at least one of the transmitting operations, the receiver receives two different digital sequences and thus detects the error.

Another important aspect of the electrical system for controlling the closure element which is electrically displaceable is safety: it is necessary to prevent movement of the closure element from inadvertently damaging objects and in particular injuring persons.

A fairly common way to obtain this result is to identify the area in which the movement of the closing element occurs and to stop this movement if an object or person enters this area.

PL 213 980 B1

The safety devices most commonly used to control areas in these applications are photoelectric systems.

As is known, a photoelectric system consists of a transmitter and a receiver, and if the system is installed correctly, when the system is active, the transmitter emits light rays which are picked up by the receiver, and if an object or person passes between the transmitter and the receiver, the light rays do not reach the receiver. and this situation is signaled by the system.

In order to properly control the area, it is often necessary to use more than one photoelectric system and the correct system along the perimeter.

Fig. 8 shows in schematic form the sliding gate CA placed between the two walls M1 and M2, two photoelectric systems FC1, FC2 composed of two transmitters FC1-T, FC2-T and two receivers FC1-R, FC2-R, respectively.

Of course, these two photoelectric systems actually control the area in which the gate CA moves, and if the person P for example crosses the line that connects the FC2-T transmitter and the corresponding FC2-R receiver, the light beam of the FC2 photoelectric system is interrupted and the gate CA stops.

In fact, the two photoelectric systems FC1 and FC2 may interfere with each other, and due to the proximity of the two systems FC1 and FC2, the light rays emitted by the transmitter of one of the two photoelectric systems reach the receiver of this photoelectric system, but also the receiver of the other photoelectric system (although with reduced intensity).

In this case and as shown in Fig. 8, there is a danger that even if a person P has entered the controlled area, the gate CA will not be stopped by the electric control system because the two receivers FC1-R and FC2-R still receive the light rays.

In order to solve this problem, it is possible to change and synchronize the operation of the two photoelectric systems and if it is assumed that the first photoelectric system FC1 is set to operate for 10 ms, then the photoelectric system FC2 is set to operate for 10 ms and that the same procedure is continued later, the interference between the two systems is eliminated.

Of course, this solution can be extended to a larger number of photoelectric systems.

Synchronization between photoelectric systems can be achieved with the appropriate system attached to them.

In the case of an electrical control system similar to that described above, it is possible to advantageously prevent this additional system, as will be described below with reference to Fig. 8.

There are four UP-4, UP-5, UP-6, UP-7 peripherals of the electric control system, which UP-4, UP-5, UP-6, UP-7 peripherals are connected to the FC1- T, to the FC1-R receiver, to the FC2-T transmitter, and to the FC2-R receiver, and the system CPU is arranged to transmit constant rate digital information packets (e.g., every 30 ms) and four UP peripherals over the network -4, UP-5, UP-6, UP-7 are positioned so that they detect packets and extract a fixed period clock signal (30 ms in this example) which will be identical for all four devices; the clock period may be divided into two equal parts, and during the first part, FC1 is energized by the UP-4 and UP-5 devices, and during the second part, FC2 is energized by the UP-6 and UP-7 devices.

A simple and advantageous way to achieve this behavioral change may be as follows.

Four device identification codes are assigned to the four peripheral devices UP-4, UP-5, UP-6, UP-7: two odd codes (which are not necessarily different) are assigned to the UP-4 and UP-5 devices, and two even codes (which are not necessarily different) are assigned to the UP-6 and UP-7 devices; the UP-4 and UP-5 devices will excite respectively the FC1-T transmitter and FC1-R receiver of the FC1 chip during the (odd) subperiod 1 of each period of the dedicated clock signal, and the UP-6 and UP-7 devices will excite the FC2-T transmitter and FC2-R receiver of FC2 during the (even) subperiod of each period of the dedicated clock signal.

Of course, these solutions can be extended to a larger number of photoelectric systems. Four chips should be sufficient to meet each requirement, in which case a change could be obtained with at least two bits of the device identification code.

PL 213 980 B1

It must not be forgotten that the sub-period must have a duration that is sufficiently long to allow reliable detection of the interruption of the light rays, and that the period must have a duration that is short enough to meet the requirements imposed by international standards.