SAFETY SWITCH

Description

[0001] The invention relates to a safety system with a safety switch.

[0002] Safety switches are used in the field of safety technology, particularly for protecting hazardous areas in systems. The term "systems" also includes machines, work equipment, and the like.

[0003] For example, such safety switches can work with transponders, whereby the transponder signals can be used to detect whether a separating protective device such as a door providing access to a system is closed or not.

[0004] Such a safety switch generally has an input / output structure with inputs and outputs, which can be configured redundantly. The safety switch generates a switching signal according to its monitoring function, particularly depending on the transponder signal, which is output to a controller used to control the system to be monitored. If the safety switch detects a safe state, in particular that a door to be monitored is closed and thus blocks access to a hazardous area in which, for example, the system is located, a switching signal with the switching state "switched on" is generated, corresponding to an active safety condition, i.e., an enable signal. If the controller receives this enable signal from the safety switch, it can start or leave the system in operation.However, if the safety switch detects an open door, it generates a switching signal with the switching state "off," corresponding to a non-active safety condition. In this case, the safety switch shuts down the system to prevent dangerous conditions.

[0005] Such a safety switch can also be assigned a start button. Manual operation of the start button can generate an acknowledgment signal for enabling the system. A user who presses the start button signals with the acknowledgment signal that no one is in the danger zone. This provides an additional safety function in addition to the monitoring function of the safety switch. Operation of the system is only enabled when the safety switch generates an enable signal for the system and when an acknowledgment signal is present with the start button. This means that dangerous situations when enabling operation of the system can be ruled out with a high degree of certainty.

[0006] DE 10 2012 103 015 A1 relates to a safety switching device for fail-safely switching a technical system on or off, comprising a fail-safe control / evaluation unit with an input for receiving an input signal. The fail-safe control / evaluation unit is designed to process the input signal in order to generate, as a function of the input signal, an output signal for switching the technical system on or off at an output signal time. The fail-safe control / evaluation unit has a first output for transmitting the output signal to an electromechanical switch. The electromechanical switch has a normally open contact for switching a load circuit of the technical system and a positively driven auxiliary contact in an auxiliary contact current path, via which a current can be conducted when a defined voltage is applied to check the switching position of the normally open contact.A switching element is arranged in the auxiliary clock current path. The fail-safe control / evaluation unit is configured to generate a switching signal at a switching signal time with a time offset from the output signal time. The fail-safe control / evaluation unit has a second output for transmitting the switching signal to the switching element, which is configured to switch the current through the auxiliary contact current path upon receipt of the switching signal.

[0007] DE 10 2010 035 765 A1 relates to a device for monitoring the state of a protective device of a machine, in particular a safety switch. The device serves to monitor the state of a protective device of a machine, wherein the device comprises a switch head and an actuator which can be brought into interaction with one another and thereby control the device. The device has a first operating mode in which, upon interaction between the actuator and the switch head, an enable signal is output at an output of the device. The device can be converted into a second operating mode by means of a locking insert which can be brought into operative connection with the switch head. In the second operating mode, no enable signal is output at the output of the device upon interaction between the actuator and the switch head.

[0008] DE 10 2005 014 122 A1 relates to a safety switching device for safely switching off an electrical load, having at least one input for connecting a signaling device. Furthermore, an evaluation and control unit is provided, as well as at least one switching element that can be controlled by the evaluation and control unit to interrupt a power supply path to the load. The evaluation and control unit is designed to perform functional tests at defined times to check at least one switching function of the at least one switching element. For connecting the signaling device, the at least one input is also designed as an input for supplying a supply voltage required for the operation of the at least one switching element.

[0009] The invention is based on the object of providing a security system with extended functionality.

[0010] To achieve this object, the features of claim 1 are provided. Advantageous embodiments and expedient developments are described in the dependent claims.

[0011] The invention relates to a safety system comprising a safety switch with an input / output structure and means for generating a switching signal for enabling the operation of a system. Manual actuation of a start button generates an acknowledgment signal for enabling the system. Operation of the system is only enabled when the safety switch generates an enable signal for the system and when an acknowledgment signal is present with the start button. The input / output structure forms connection means for connecting the start button. The connection means are automatically detected in the safety switch. When the safety switch is in operation, with or without a start button, different wiring of inputs and / or outputs of the input / output structure is present, which is detected in the safety switch. The connection of the start button is detected in the safety switch during a commissioning phase.

[0012] The integration of the start button into the operation of the safety switch is generally achieved by making the acknowledgement signal generated in the start button available in the safety switch and passing it on, with or without its own evaluation, to another unit, in particular to a higher-level control system that controls the operation of the system.

[0013] The automatic detection of the connection of the start button by the safety switch not only achieves an automated process for the safety switch itself, but also for the entire safety system in which the safety switch is integrated.

[0014] According to the invention, whether a start button is connected to the safety switch or not is detected by detecting specific connection elements on the input / output structure of the safety switch. Depending on whether a start button is present or not, different connection elements are present on the input / output structure, in particular different wiring at the inputs and outputs of the input / output structure, which can be detected as control signals in the safety switch. Based on these control signals, it can be reliably distinguished whether a start button is present or not.

[0015] It is particularly advantageous to use an intermediate plug as wiring for connecting the start button.

[0016] The intermediate plug connected to the inputs and / or outputs of the input / output structure of the safety switch can be clearly identified by means of control signals received in the safety switch, which allows the connection of the start button to be reliably detected.

[0017] According to the invention, the connection of the start button is detected during a commissioning phase. This commissioning phase is, in particular, the start-up phase during each device start-up before the start of normal operation, i.e., working mode.

[0018] In particular, it generates a control signal during the commissioning phase. Depending on the readability of the control signal, the connection of the start button is detected.

[0019] This design is advantageous because, even before operating mode begins during the commissioning phase, the safety switch automatically determines whether a start button is assigned to it. The safety switch then automatically adjusts its function and is then operational during the subsequent operating mode without any additional configuration or parameterization processes.

[0020] Particularly advantageous is the use of the existing control signal used for commissioning the safety switch to detect the connection of a start button, which minimizes the signal processing effort in the safety switch required to detect the connection of the safety switch. This takes advantage of the fact that the control signal read back into the safety switch is clearly dependent on whether a start button is present or not due to the characteristic wiring of the start button.

[0021] In principle, only a single safety switch can be provided, in particular as part of a safety system for safely enabling the operation of a system.

[0022] According to an advantageous embodiment of the invention, a series connection of safety switches is provided as part of a safety system. Such a multiple arrangement of safety switches can also be used to implement complex monitoring functions.

[0023] In such a series circuit, each safety switch is conveniently assigned a plug, which connects the safety switch to the series circuit. Direct wiring can also be provided instead of a plug.

[0024] This connector is designed in particular as a Y-connector such that it has a first connection side for connecting the safety switch and two further connection sides, one of these connection sides being used for connection to the preceding and subsequent Y-connector of the series circuit.

[0025] When operating without a start button, a safety switch is connected directly to the plug. The plug contains a bridge that bridges one input and one output of the safety switch.

[0026] The bridge forms a characteristic wiring that allows the safety switch to detect that there is no start button.

[0027] The bridge reads back a control signal via the input into the safety switch, which signals the direct connection of the plug to the safety switch.

[0028] In this way, the safety switch can easily and safely detect that there is no start button.

[0029] When operated with a start button, the start button is connected between a safety switch and its associated connector, particularly a Y-connector. For such a connection, an intermediate connector is preferably used, which bypasses the bridge in the connector.

[0030] The start button is connected to an input of the safety switch via the adapter plug. A control signal is generated at the input, indicating the connection of the start button.

[0031] The connection of the intermediate plug thus forms a characteristic wiring, which can be clearly identified by reading back the control signal generated in the safety switch as a function of this wiring, whereby the connection of the start button is reliably detected.

[0032] The invention is explained below with reference to the drawings. They show: Figure 1: Schematic representation of a series connection of safety switches. Figure 2: Series connection according to Figure 1 with start buttons assigned to the safety switches. Figure 3: External wiring of an input and output of a safety switch when operating without a start button. Figure 4: External wiring of an input and output.

[0033] Figure 1 shows a highly schematic series circuit consisting of a multiple arrangement of safety switches 1.

[0034] Figure 1 shows a series connection of two identically designed safety switches 1. However, the safety switches 1 do not necessarily have to be identical. In general, the series connection can also have a different number of safety switches 1. Finally, a single safety switch 1 can also be used.

[0035] The safety switches 1 are used in the field of safety technology. In particular, a safety switch 1 monitors whether a separating protective device, such as a door, is closed, preventing access to a hazardous area in which a hazardous installation is located. The closed position of the door can be controlled using transponder signals. A transponder can be arranged in an actuator that is attached to the door and can move with it. The safety switch 1 is then arranged on a frame that restricts access. When the door is in the closed position, the transponder is within the reading range of an RFID reader arranged in the safety switch 1, so that the reader can receive the transponder signals from the transponder.

[0036] How Figure 1shows, each safety switch 1 has an eight-pole input / output structure, from which a cable arrangement 2 with eight cables is led to a connector 3, which is designed as a Y-connector, i.e. as a three-way switch. In the Y-connector, the connections to the connector 3 are converted into connections for the connectors 3 to one another. The connector 3 has two connection sides, each with five connections, whereby a connector 3 can be connected with one connection side to the preceding connector 3 and with the other connection side to the subsequent connector 3, so that the connectors 3 are connected to one another with a cable arrangement 4 of five cables. This connection diagram is not mandatory; in particular, the safety switch 1 and the associated connector 3 can each have other connection patterns. Furthermore, wiring can also be provided instead of a connector 3.

[0037] Figure 2shows a variant of the series connection, which differs from the series connection according to Figure 1 is extended in such a way that a start button 5 is arranged between a safety switch 1 and the plug 3.

[0038] Each start button 5 can be manually operated by a user, generating an acknowledgement signal that is fed to the associated safety switch 1. With the acknowledgement signal, the user acknowledges, for example, that no one is in the danger zone.

[0039] The presence of the acknowledgement signal of each start button 5, in addition to an enable signal generated in the safety switch 1, is a necessary condition for starting the operation of the system.

[0040] The acknowledgment signals are linked to the release signals generated in safety switch 1 or passed on together via the series connection and thus made available to the higher-level control system. The control system only enables operation of the system when each safety switch 1 generates a release signal and each start button 5 generates an acknowledgment signal.

[0041] Figure 3 shows a safety switch 1 which is integrated into the series circuit according to Figure 1.

[0042] The eight-pin input / output structure includes connections a, d for a supply voltage, two inputs b, c as a redundant input structure, two outputs f, g as a redundant output structure, a communication connection h, and a start input e. Inputs b, c are safety inputs through which switching signals from the preceding safety switch 1 are read. Accordingly, outputs f, g are safety outputs for outputting switching signals to the following safety switch 1.

[0043] The series connection according to Figure 1 is operated without start button 5, so that the safety switch 1 is connected directly to the plug 3. In the plug 3 there is a bridge 6, which, as Figure 3 shows, the output f and the start input e are bridged. The control signal generated during the commissioning phase is read back into the start input e via bridge 6.

[0044] Figure 4shows the safety switch 1 according to Figure 3 for integration into the series circuit according to Figure 2 , that is, in this case there is a start button 5 between the safety switch 1 and the plug 3.

[0045] The start button 5 is connected to the safety switch 1 via an intermediate plug 7, which is connected to the start input e and to the supply voltage connection a. This intermediate plug 7 bypasses the bridge 6 in connector 3.

[0046] In this case, during the commissioning phase, a static signal, specifically a low signal, is received as a control signal by connecting the intermediate plug 7. This control signal is clearly different from the cyclically varying control signal when a start button 5 is connected.

[0047] Thus, during the commissioning phase, the control signals in safety switch 1 clearly detect whether a start button 5 is present or not. Once the start button 5 is connected, safety switch 1 can integrate it into operation without the need for separate configuration or parameterization processes. This means that safety switch 1 can easily switch from the commissioning phase to operating mode. List of reference symbols

[0048] (1)Safety switch (2)Wiring arrangement (3)Plug (4)Wiring arrangement (5)Start button (6)Bridge (7)Intermediate plug

Claims

1. Safety system with a safety switch (1) with an input / output structure and with means for generating a switching signal for enabling the operation of a system, and with a start button (5), wherein an acknowledgement signal for enabling the system is generated by manual actuation of the start button (5), wherein the operation of the system is only enabled when the safety switch (1) generates an enable signal for the system and when an acknowledgement signal is present with the start button, characterised in that the input / output structure forms connection means for connecting the start button (5), and in that the connection means are automatically detected in the safety switch (1), in that during operation of the safety switch (1) with or without the start button (5) there are different wirings of inputs and / or outputs of the input / output structure, which are detected in the safety switch (1), and in that the connection of the start button (5) is detected in the safety switch (1) during a commissioning phase.

2. Safety system according to claim 1, characterised in that an adapter plug (7) is provided in the safety switch (1) as wiring for connecting the start button (5).

3. Safety system according to one of claims 1 or 2, characterised in that the safety switch (1) generates a control signal during the start-up phase, the connection of the start button (5) being detected as a function of the read-back capability of the control signal.

4. Safety system according to one of claims 1 to 3, characterised in that this has a series connection of several safety switches (1).

5. Safety system according to claim 4, characterised in that a plug (3) or wiring for connection to the series connection is assigned to the safety switch (1).

6. Safety system according to claim 5, characterised in that the safety switch (1) is connected directly to the plug (3) during operation without a start button (5), a bridge (6) bridging an input and an output of the safety switch (1) being present in the plug (3) or in the wiring.

7. Safety system according to claims 3 and 6, characterised in that the jumper (6) reads back the control signal via the input to the safety switch (1), which signals the direct connection of the plug (3) or the wiring to the safety switch (1).

8. Safety system according to claim 5, characterised in that a start button (5) is connected between the safety switch (1) and the plug (3) or the wiring.

9. Safety system according to claims 2 and 8, characterised in that the start button (5) is connected to an input of the safety switch (1) by means of the intermediate plug (7), a control signal being generated at the input which signals the connection of the start button (5).

10. Safety system according to claim 6, characterised in that the intermediate plug (7) forms a bypass of the bridge (6) of the plug (3) or the wiring.