Electronic security equipment for a machine or industrial

Abstract

Electronic security equipment for machines or industrial facilities and related security methods are disclosed. An electronic safety device includes a safety switch and an actuator. The safety switch comprises a switching device, a control unit and an antenna circuit, the switching device being configured to assume an active or inactive state and to send a safety signal to enable activation of the machine or facility. The antenna circuit includes a resonant circuit having a plurality of tuning auxiliary elements arranged in parallel with at least one first inductor and at least one first capacitor. There is also provided a selection device associated with the tuning auxiliary elements and configured to include one or more tuning auxiliary elements in the resonant circuit or to exclude one or more tuning auxiliary elements from the resonant circuit, to modify the inductance and / or capacitance of the resonant circuit and to obtain a desired tuning frequency value of the resonant circuit.

Description

Technical Field

[0001] The present invention generally relates to electronic safety equipment for industrial machines and facilities.

[0002] The present invention belongs to the technical field of safety devices, in particular to the technical field of safety devices applied to machines and / or industrial facilities.

[0003] In particular, the context of the present invention is an RFID type electronic safety switch. In this case, the safety switch must at least detect a nearby appropriate actuator in order to activate its safety output and thereby send a consistent signal for safely starting a machine and / or industrial facility.

[0004] Depending on requirements and needs, the equipment object of the present invention can also be applied to provide a safety switch for locking an actuator; in this case, the safety switch must necessarily detect the correct actuator in the vicinity (closed guard) and lock it to itself (closed and locked guard) in order to activate its safety output. Background Art

[0005] In industrial environments, a large number of industrial machines of varying complexity, size and difficulty of use are used every day.

[0006] This type of industrial machinery presents many hazards and factors that must be noted due to its composition and use.

[0007] In practice, systems and devices are used to guard passages and hazardous areas of such industrial machines in order to protect users and operators.

[0008] Traditionally, passageways are protected by guards, such as doors, gates, shutters, covers and other elements or devices which, when closed, prevent users from being able to reach hazardous areas or accidentally come into contact with such industrial machinery or equipment.

[0009] In order to monitor the state of the guard protecting the passage, it is known to use an electronic security system which generally comprises a first device attached to a fixed part of the guard and a second device attached to a movable part of the guard so that when the passage is closed, the second device approaches the first device.

[0010] Typically, the first device includes antenna circuitry to identify when the second device is in proximity to the first device in wireless mode.

[0011] To achieve this, the second device then comprises an RFID transponder which generates a response signal when stimulated by the signal transmitted by the antenna circuit.

[0012] This response signal is then received by the antenna circuit and can be processed by the first device, causing it to recognize that the second device is in its vicinity and that the protective device is therefore closed.

[0013] A disadvantage of the known device is that the electronic components in the antenna circuit typically have effective values ​​within a rather wide tolerance range from their nominal purchased values. For example, an inductor or a capacitor may have a tolerance of + / - 10% from the nominal value of their inductance or capacitance. As a result, the actual resonant frequency of the antenna circuit of the known device may also be far from its nominal resonant frequency.

[0014] This has a very negative impact on the performance of the antenna circuit of the device, such as for example low accuracy in identifying the transponder or performance variability between different devices.

[0015] These disadvantages are further exacerbated if the known devices are installed and used in an environment subject to high temperature variations, such as on the order of 90-100° C. or higher. Summary of the invention

[0016] Therefore, an object of the present invention is to provide an electronic security device that can solve the above-mentioned inconveniences and critical problems.

[0017] Another object of the present invention is to provide an electronic safety device capable of protecting and guarding passageways and hazardous areas of industrial machines.

[0018] Yet another object of the present invention is to provide an electronic safety equipment for controlling and managing mobile protection devices and other safety elements already known and existing on the market.

[0019] Another object of the present invention is to provide electronic safety equipment capable of managing the tolerances of the various components.

[0020] A further object of the invention is to provide an electronic safety equipment capable of adapting its characteristics to the temperature of the environment in which it is installed.

[0021] Another object of the invention is to provide an electronic safety device that is simple and inexpensive to implement.

[0022] It is yet another object of the present invention to provide electronic safety equipment that can be easily installed and used on new or existing industrial machines and systems.

[0023] These and other objects are achieved by an electronic security arrangement according to the attached independent claims.

[0024] Further detailed features are given in the attached dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The invention will now be described by way of example and not limitation according to some preferred embodiments of the invention and with the aid of the accompanying drawings, in which:

[0026] Figures 1 to 4 is a schematic representation of components of electronic security equipment according to respective embodiments of the present invention;

[0027] Figures 5 to 8 is a schematic representation of components of electronic security equipment according to respective embodiments of the present invention;

[0028] Fig. 9 is a schematic top view of a machine protected by a protective device using the electronic safety equipment according to the present invention;

[0029] Fig.10 is a flow chart showing how the electronic security equipment according to the present invention operates. DETAILED DESCRIPTION

[0030] With reference to the mentioned drawings, there is shown a preferred embodiment of the electronic security equipment according to the present invention.

[0031] Referring to the above drawings, the electronic safety device 1 of the present invention includes a first electronic safety device (hereinafter referred to as a safety switch 11) and a second electronic safety device (hereinafter referred to as an actuator 12), wherein the safety switch 11 is fixed to a fixed part 41 of a protective device 40 of a protective barrier 43 for a machine 50 or an industrial facility, for example, and the actuator 12 is fixed to a movable part 42 of the protective device 40 itself. Figure 5 , a safety switch 11 and an actuator 12 mounted on a guard 40 of, for example, an industrial machine 50 can be seen.

[0032] Reference again Figure 5 , the guard device 40 includes a door, wherein the safety switch 11 is fixed to a fixed frame 41 (fixed part) of the door and the actuator 12 is fixed to a blade 42 (movable part) of the door.

[0033] When the door is closed, the safety switch 11 detects the approach of the actuator 12, which means that the door is closed.

[0034] In a first embodiment according to the invention, the actuator 12 comprises a transponder 63 and the safety switch 11 comprises a switching device 30, a control unit 20 and an antenna circuit 10 configured to stimulate the transponder 63 to detect its presence when the actuator 12 approaches the safety switch 11.

[0035] The switching device 30 is controlled by the control unit 20 and can assume an active state and an inactive state that can be distinguished from each other.

[0036] In this example, the switching device 30 comprises one or more safety outputs 31 of the OSSD (Output Signal Switching Device) type, each of which can present at least an active state and an inactive state that can be distinguished from each other.

[0037] By way of example only, an active safety output transmits a signal and assumes a logical state of "1" or "ON", while an inactive safety output does not transmit a signal and assumes a logical state of "0" or "OFF".

[0038] Even more preferably, the switching device 30 comprises at least two independent and redundant safety outputs 31 of the OSSD type.

[0039] In other possible embodiments, the switching device 30 may also be other known types and include electronic contacts of mechanical, electromechanical, relays, or any other electrical, electronic or electromechanical components, which can selectively switch from an active state (where signal transmission is allowed) to an inactive state (where signal transmission is not allowed).

[0040] The switching device 30 is connected to a communication interface (not shown) that is configured to transmit one or more signals (associated with the state of the switching device 30) to one or more command devices 51 external to the safety switch 11. Specifically, the communication interface is configured to transmit at least one signal encoding the state of the switching device 30.

[0041] Merely by way of example, the communication interface may comprise one or more connectors or a communication bus such as of IO-Link, IO-Link Safety or ProfiSafe or ProfiNet type, or it may be wireless or it may be implemented in any combination mentioned or known in the art.

[0042] In use, the communication interface may be linked or connected to a command device 51 configured to control the installation or machine 50 based on a signal associated with the state of the switching arrangement 30 .

[0043] The command device 51 may include a PLC or a safety module or a contactor or other similar or assimilated device connected to the power supply of the facility or machine 50 or any combination thereof.

[0044] For example, if the state of the switching device 30 is inactive, the control device will not allow the machine 50 to start or interrupt its operation.

[0045] Alternatively, the communication interface may be linked or connected directly to the machine 50 .

[0046] The antenna circuit 10 of the safety switch 11 is configured to detect whether the actuator 12 approaches the safety switch 11 and to transmit a presence signal A directly or indirectly to the control unit 20 if such an approach is detected.

[0047] The activation of the switching device 30 by the control unit 20 is performed at least on the basis of said presence signal A.

[0048] For example, if there is a signal A conveying that the actuator 12 is approaching the safety switch 11 , in other words that the guard device 40 is closed, the control unit 20 may be configured to activate the switching device 30 .

[0049] Otherwise, in the case where the safety switch 11 also includes a locking mechanism (not shown) for mechanically or magnetically locking the actuator 12 to itself by means of an electromagnetic field, the control unit 20 can be configured to activate the switching device 30 if there is a signal A indicating that the actuator 12 is approaching the safety switch 11 and if it is simultaneously detected that the actuator 12 is also locked by the locking mechanism, in other words, the guard device 40 is closed and locked.

[0050] In such cases, the switching device 30 sends a safety signal B indicating that the machine 50 is in a safe state and can therefore be started.

[0051] For example, in an embodiment in which the switching device 30 includes two safety outputs 31OSSD, the safety signal B is recognized in the active state of both safety outputs 31OSSD, or alternatively, the first safety output 31OSSD is activated when the protective device is closed, and the second safety output 31OSSD is activated when the protective device is locked.

[0052] In an exemplary and preferred embodiment, the control unit 20 comprises at least a first microcontroller 1 and at least a second microcontroller 2 interconnected to each other so as to communicate redundantly ( Figures 1 to 4 ). In other embodiments not shown, the control unit 20 comprises a single microcontroller that performs the functions of the two microcontrollers 1 and 2 .

[0053] Advantageously, the two microcontrollers 1 and 2 are connected to the switching means 30 to control them and switch them from an active state to an inactive state or vice versa. For example, in an embodiment in which the communication means 30 comprises two safety outputs 31OSSD, the first microcontroller 1 is connected to the first safety output and the second microcontroller 2 is connected to the second safety output.

[0054] The antenna circuit 10 comprises a resonant circuit 6 including at least one first inductor 61 connected in parallel with at least one first capacitor 62 and a plurality of tuning auxiliary elements 7 .

[0055] As will be described in detail below, when the resonant circuit 6 is powered, it excites the transponder 63 of the actuator 12 which modulates the field generated by the resonant circuit 6 by changing the shape of its oscillating wave and generating a presence signal A.

[0056] Preferably, the tuning auxiliary element 7 comprises a plurality of auxiliary capacitors ( Figures 1 to 4 ).

[0057] Alternatively, in an embodiment not shown, the tuning element 7 comprises a plurality of auxiliary inductors arranged in parallel with the first inductor 61 and the first capacitor 62 .

[0058] In the diagram of only the resonance circuit 6 Figure 5 and Figure 7 In a further embodiment schematically represented in FIG. 8 , the tuning auxiliary element 7 comprises at least one auxiliary capacitor arranged in series with the first capacitor 62 .

[0059] In the diagram showing only the resonant circuit 6 Figure 6 and Figure 8 In other possible embodiments schematically shown in FIG. 8 , the auxiliary tuning element 7 comprises at least one auxiliary inductor arranged in series with the first inductor 61 .

[0060] The safety switch 11 further comprises selection means 3 associated with the tuning auxiliary elements 7 and configured to include one or more of the tuning auxiliary elements 7 in the resonance circuit 6 or to exclude one or more of the tuning auxiliary elements 7 from the resonance circuit 6. Thus, by means of the selection means 3 it is possible to modify the overall inductance and / or capacitance of the resonance circuit 6 and obtain a desired value for its tuning frequency.

[0061] Advantageously, in this way, even in the case where the actual values ​​of the inductance and capacitance of the first inductor 61 and the first capacitor 62 do not correspond to their respective nominal values, it is possible to enable or disable one or more tuning auxiliary elements 7 to obtain a desired frequency, for example but not necessarily 125 KHz or other frequencies. This makes it possible to industrially produce safety switches 11 whose respective resonant circuits are always tuned to the same desired tuning frequency, guaranteeing the desired performance of all safety switches 11 produced, minimizing production waste and reducing production time and costs.

[0062] In fact, by varying the capacitance or inductance of the resonant circuit 6 its frequency can be tuned to a desired frequency.

[0063] For example, in the case where the antenna is to be tuned to 125 KHz, if the starting frequency of the resonance circuit 6 is greater than 125 KHz, capacitance is added in parallel or in series with the first inductor 61 and / or the first capacitor 62, and if the starting frequency is on the contrary less than 125 KHz, capacitance is removed in parallel or in series with the first inductor 61 and / or the first capacitor 62. In fact, when tuning the antenna circuit 10, in order to achieve the desired tuning frequency, the control unit 20 will include one or more tuning auxiliary elements 7 with their corresponding capacitances in the resonance circuit 6 or exclude one or more tuning auxiliary elements 7 with their corresponding capacitances from the resonance circuit 6 by means of the selection device 3.

[0064] The selection means 3 are controlled by a control unit 20 and may comprise, for example, one or more switches 14 , each of which is electrically associated with at least one respective tuning aid element 7 to include the tuning aid element 7 in the resonance circuit 6 or to exclude it from the resonance circuit 6 .

[0065] For example, in an embodiment in which the tuning auxiliary element 7 is electrically connected in parallel with the first inductor 61 and the second inductor 62, each switch 14 is arranged electrically in series with the corresponding tuning auxiliary element 7. In this case, when the switch 14 is opened, the corresponding associated tuning auxiliary element 7 is excluded from the resonance circuit 6. In addition, when the switch 14 is closed, the corresponding associated tuning auxiliary element 7 is included in the resonance circuit 6.

[0066] Alternatively, in an embodiment in which the tuning auxiliary element 7 is electrically connected in series with the first inductor 61 or the second inductor 62, each switch 14 is arranged electrically in parallel with at least one tuning auxiliary element 7 ( Figures 5 to 8 ). In this case, when the switch 14 is closed, the respective associated tuning auxiliary element 7 is bypassed, which will thus be excluded from the resonant circuit 6. Furthermore, when the switch 14 is open, the respective associated tuning auxiliary element 7 is included in the resonant circuit 6.

[0067] The switch 14 may be of MOS, MOSFET, transistor, electromechanical or other type.

[0068] It should be noted that the location of the device 3 in the accompanying drawings is chosen for illustrative purposes only and is not limiting.

[0069] In one embodiment, the selection device 3 is integrated in the control unit 20 , for example in one of the first microcontroller 1 or the second microcontroller 2 .

[0070] In another embodiment, the selection device 3 is outside the control unit 20 and is controlled by one of the first microcontroller 1 or the second microcontroller 2 ( Figure 1 and Figure 2 ).

[0071] In another embodiment, the control unit 20 includes a third microcontroller 5 ( Figure 3 and Figure 4 ) and the selection device 3 is outside the third microcontroller 5 and controlled by the third microcontroller 5. In a further embodiment, the third microcontroller 5 comprises the selection device 3. In this case, the third microcontroller 5 is preferably a programmable logic component, for example, a FPGA (Field Programmable Gate Array) or a CPLD (Complex Programmable Logic Device) type.

[0072] Preferably, the third microcontroller 5 also comprises an internal memory in which stored information encodes the combination of tuning auxiliary elements 7 to be excluded or activated in order to obtain the correct tuning at the desired frequency (eg 125 KHz).

[0073] When the electronic safety equipment is in use, one of the first microcontroller 1 and the second microcontroller 2 reads information in the internal memory of the third microcontroller 5 encoding the combination of tuning auxiliary elements 7 to be excluded.

[0074] After taking this reading, the first microcontroller 1 or the second microcontroller 2 taking this reading communicates to the third microcontroller 5 , which selects the means 3 to operate so as to exclude or include the tuning auxiliary elements 7 necessary to obtain the desired tuning of the resonant circuit 6 .

[0075] The resonant circuit 6 can be directly connected to the control unit 20 in order to be powered thereby and to transmit the presence signal A ( Figure 1 and Figure 3 ).

[0076] Alternatively, the antenna circuit 10 may include a signal processing unit 4 ( Figure 2 and Figure 4 ), which is connected to the resonance circuit 6 to feed it and process the signal generated by it. The signal processing unit 4 is then configured to transmit to the control unit 20 a digital presence signal A obtained by processing the analog signal output from the resonance circuit 6.

[0077] The signal processing unit 4 may include a control circuit 41 , a peak detector 42 , a filter stage 43 and a decoder stage Manchester 44 .

[0078] The control circuit 41 generates a sinusoidal signal having a frequency that is related to the ratio of the inductance to the capacitance of the resonant circuit 6 and feeds it to the resonant circuit 6 .

[0079] The control circuit 41 is also connected to the control unit 20, which controls its activation and operating voltage, in other words the voltage between the peak and valley values ​​and the average voltage of the sinusoidal signal.

[0080] By way of example, one of the first microcontroller 1 and the second microcontroller 2 transmits a signal to the third microcontroller 5 requesting the on / off of the control circuit 41 and encoding the voltage and the average voltage between the peak and valley values ​​at which the oscillating circuit 41 is to work ( Figure 4 ). The third microcontroller 5 then controls the activation of the control circuit 41 and sets its operating voltage. Alternatively, in an embodiment in which the third microcontroller 5 is not provided, one of the first microcontroller 1 and the second microcontroller 2 directly controls the activation of the control circuit 41 ( Figure 2 ).

[0081] When the resonant circuit 6 is energized, it excites the transponder 63 of the actuator 12 , which modulates the field generated by the resonant circuit 6 by changing the shape of the oscillating wave.

[0082] The peak detector 42 of the signal processing unit 4 is then configured to detect the difference between the peaks of the waves modified by the transponder 63 of the actuator 12 and to generate an analog signal. The peak detector 42 is connected to the filter stage 43 to transfer said analog signal thereto.

[0083] The filter stage 43 is configured to filter this analog signal in order to remove any noise and generate a filtered signal. The filter stage 43 is in turn connected to a decoding stage Manchester 44 to transmit the filtered signal to the decoding stage 44.

[0084] The decoding stage Manchester 44 is configured to digitize this filtered signal. By way of example, the decoding stage Manchester 44 generates a digital binary signal. This digital binary signal corresponds to the presence signal A and includes the identification code of the transponder 63 of the actuator 12. The decoding stage Manchester 44 is connected to the control unit 20 to send the presence signal A to the control unit 20.

[0085] The control unit 20 activates or deactivates the switching device 30 and thus the safety output 31 OSSD based at least on the presence signal A to send a safety signal B indicating that the machine 50 or the industrial facility is in a safe state and can be started.

[0086] Optionally, the safety switch 11 comprises at least one auxiliary sensor (not shown) configured to detect at least one environmental parameter and connected to the control unit 20. For example, the auxiliary sensor may be configured to detect the temperature of the environment in which the safety switch 11 is located.

[0087] In this case, the control unit 20 is also configured to control the selection means 3 as a function of the environmental parameters detected by the auxiliary sensor.

[0088] By way of example, a characteristic curve may be stored in the control unit 20, which relates values ​​of an environmental parameter to capacitance values ​​of the resonance circuit 6 suitable for ensuring a desired tuning of the resonance circuit 6. In this way, as the environmental parameter changes, the control unit 20 may control the selection means 3 to change the capacitance value of the resonance circuit 6 as a function of the measured environmental parameter.

[0089] Fig.10 An exemplary block diagram showing the working steps of the electronic security equipment 1 object of the present invention.

[0090] from Fig.10 It can be seen that its logo:

[0091] - a first step 101 according to which the antenna circuit 10 detects the proximity of the actuator 12 to the safety switch 11 when the protection device 40 is closed;

[0092] - a second step 102 , according to which the antenna circuit 10 sends a presence signal A to the control unit 20 ;

[0093] - a third step 103 , according to which the control unit 20 activates the switching means 30 ;

[0094] A fourth step 104 , according to which the switching device 30 sends a safety signal B which indicates that the system or machine 50 is in a safe state and can be started.

[0095] In some embodiments, there is also a step 105 whereby the safety switch 11 locks the actuator 12 onto itself.

[0096] The invention also relates to a safety system comprising a machine 50 or an industrial installation and an electronic safety device 1 according to the invention.

[0097] From the description given, the characteristics of the electronic security equipment which is the object of the present invention are clear, which are its advantages.

[0098] Finally, it is obvious that many other modifications could be made to the equipment discussed without departing from the principle of novelty inherent in the inventive concept, just as it is obvious that in a practical implementation of the invention, the materials, shapes and dimensions of the details shown may be any according to requirements and that equivalent details may be substituted for the same.

[0099] In case features and techniques mentioned in any claim are followed by reference numerals, such reference numerals have been attached for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference numerals have no limiting effect on the interpretation of each element identified by way of example through such reference numerals.

Claims

1. An electronic safety device (1), comprising a safety switch (11) and an actuator (12), the safety switch (11) and the actuator (12) being configured to be associated with a guard (40) of a machine (50) or an industrial facility and to interact when the guard (40) is opened and closed, wherein: The safety switch (11) comprises: a switching device (30) configured to assume an active state or an inactive state and to send a safety signal (B) to enable the machine (50) or the facility to be started; a control unit (20) connected to the switching device (30) and configured to activate the switching device at least in response to a presence signal (A) indicating that the actuator (12) is in proximity to the safety switch (11); an antenna circuit (10) configured to detect whether the actuator (12) is close to the safety switch (11) and to send the presence signal (A) to the control unit (20); The antenna circuit (10) comprises at least one resonant circuit (6), the at least one resonant circuit (6) in turn comprising at least one first inductor (61) and at least one first capacitor (62) and a plurality of tuning auxiliary elements (7); The electronic safety equipment (1) further comprises a selection device (3), which is associated with the tuning auxiliary element (7) and is configured to include one or more of the tuning auxiliary elements in the resonant circuit (6) or exclude one or more of the tuning auxiliary elements (7) from the resonant circuit (6) to modify the inductance and / or capacitance of the resonant circuit (6) and obtain a desired tuning frequency value of the resonant circuit (6).

2. The electronic safety equipment according to claim 1, wherein: The actuator (12) includes a transponder (63) and the antenna circuit (10) is configured to activate the transponder (63) when the actuator (12) is in proximity to the safety switch (11) to detect its presence.

3. Electronic safety equipment according to at least one of the preceding claims, wherein: The control unit (20) comprises a first microcontroller (1) and a second microcontroller (2), the first microcontroller (1) and the second microcontroller (2) being interconnected to each other so as to communicate in a redundant manner and being connected to the switching device (30) for controlling them and switching them from an active state to an inactive state and vice versa.

4. Electronic safety equipment according to at least one of the preceding claims, wherein: The tuning auxiliary element (7) comprises at least one auxiliary capacitor or auxiliary inductor arranged in parallel with the first inductor (61) and the first capacitor (62).

5. The electronic safety equipment according to at least one of claims 1 to 4, wherein: The tuning auxiliary element (7) comprises at least one auxiliary inductor or capacitor arranged in series with the first inductor (61) or the first capacitor (62), respectively.

6. Electronic safety equipment according to at least one of the preceding claims, wherein: The selection device (3) is controlled by the control unit (20) and comprises one or more switches (14), each of which is arranged electrically in parallel or in series with a corresponding tuning auxiliary element (7).

7. The electronic safety equipment according to any one of claims 3 to 6, wherein: The control unit (20) comprises a third microcontroller (5) and the selection device (3) is controlled by the third microcontroller (5).

8. The electronic safety equipment according to claim 7, wherein: The third microcontroller (5) comprises the selection means (3) and is preferably of CPLD type or FPGA type.

9. Electronic safety equipment according to at least one of the preceding claims, wherein: The antenna circuit (10) comprises a signal processing unit (4) connected to the resonance circuit (6) and configured to transmit the presence signal (A) in a digital form obtained by processing an analog signal output from the resonance circuit (6) to the control unit (20).

10. An electronic safety device according to any one of the preceding claims 9, wherein: The safety switch (11) comprises at least one auxiliary sensor configured to detect at least one environmental parameter connected to the control unit (20), and wherein the control unit (20) is configured to control the selection device (3) according to the environmental parameter detected by the auxiliary sensor.

11. A safety system comprising a machine (50) or an industrial installation and a safety electronic device (1) according to at least one of the preceding claims, wherein: The switching device (30) is connected to a communication interface, which is configured to transmit one or more signals associated with the state of the switching device (30) to a command device (51) outside the safety switch (11), and the command device (51) is configured to command the machine (50) or facility based on the signal associated with the state of the switching device (30).

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