Safety switching device module arrangement

p0001The present invention relates to the use of a safety switch module assembly with at least one input module for processing signals from a safety sensor and for producing output signals, and having at least two output modules for activating an actuator, the input module and the output modules being arranged in a row and a module row And wherein the input module is assigned to an output module.

p0002Safety switches are generally known. They serve to reliably evaluate the signal of a safety device, for example an emergency stop switch, a protective door position switch etc., and to drive one or more safe output contacts of an output circuit. Actuators, for example contactors, valves, motors, dangerous machine parts, for example saw blades, robot arms, high-voltage devices, etc., are then brought into a safe state via these output contacts. The applicant provides a variety of different types of safety switch under the name "PNOZ". Furthermore, various variants of safety switching devices are shown in "Machine safety", Winfried Gräf, Hüthig Verlag, 1997. Furthermore,<patcit id="pcit0001" dnum="DE19736183C1"><text>DE 197 36 183 C1</text></patcit> A safety switch is known.

p0003In practice, it is very often the case that a plurality of switch events, for example the actuation of an emergency stop switch, have to be AND-linked, for example, to open a door or to pass through a light curtain. For this purpose, a plurality of safety switching devices are connected in series, the output terminals of a safety switching device being connected to the input terminals of the subsequent safety switching device.

p0004In many cases, in addition to the AND operation, a hierarchical design of the safety switching devices is desired in order, for example, to stop the entire machine with a switch event, for example the emergency stop switch, and to switch off only a specific motor of the motor with other switch events, for example a protective door switch The whole machine. Such a hierarchical structure has hitherto been possible via corresponding wiring and has proven itself in practice to be quite satisfactory.

p0005Nevertheless, the desire remains to allow a simpler and cheaper construction without compromising safety.

p0006Against this background, the object of the present invention is to enable a flexible connection of the used safety switching devices without having to carry out additional wiring of the individual safety switching devices.

p0007The object on which the invention is based is solved with a use according to claim 1.

p0008With the use according to the invention it is thus possible to select the assignment of the input module to one or both output modules by providing the input module at a specific position within the module series. In the context of this invention, the term "allocation" is understood to mean that a signal connection of direct or indirect type exists between the input module and the "assigned" output module so that the output module controls the connected actuator dependent on the output signal of the assigned input module.

p0009The user of the safety switch module arrangement is thus able to modularly configure a system according to his needs by freely selecting the assignment of the input modules to the output modules and thus the linking of the signals from the safety sensors. Depending on its position within the module row, the input module can act on the first output module, on the second output module or on both output modules. A (input) module acting on both output modules serves for the central actuation of both output modules, while the assignment of an input module to a single output module only actuates this output module.

p0010The use according to the invention thus enables the user to have a very flexible and simple design of a safety switching device system in which the safety switching devices can be connected to one another in different ways, the link being determined by the corresponding selection of the position of the input module within the module series without changing the wiring To carry out.

p0011In a further development, at least one input module module is provided for accommodating one input module and at least one first and one second module module for receiving one output module, at least one input module location being assigned to the first output module location, at least one further input module location being assigned to the second output module location and at least one further input module location First and second output module locations.

p0012In this embodiment, fixed module locations are provided, for example in a housing, which are connected, for example, to output module locations via a fixed wiring. Based on an allocation table, the user can assign input modules to specific output modules by selecting the appropriate input module locations according to his needs. Due to the fixed assignment of input module locations to output module locations, a simple configuration can be realized which does not need any control modules, etc.

p0013In a further development, each input module location has an output terminal and each output module location has an input terminal, an electrical connection being provided between the respective output terminal of the input module location and the input terminal of the output module location in accordance with the assignment of input module modules to the output module locations.

p0014These measures have the advantage that a secure, software-independent, hard-wired solution is created in which the allocation of individual module locations for input modules to module locations for output modules is fixed and is thus simple to handle and inexpensive. Although a fixed wiring is present, a very flexible system of safety switching devices can be constructed, but the possibilities of allocation are limited by the fixed wiring within a predetermined range. However, such a solution satisfies the requirements in many cases.

p0015In a further embodiment, a control module is provided, which controls the assignment of input module locations and output module locations.

p0016This measure has the advantage that the limits of flexibility given in the hard-wired solution are canceled. Rather, the control module allows any assignment of input modules to output modules. Preferably, the control module comprises a control device with a storage unit in which an allocation table defining the allocation is stored. Preferably, the control device is designed as a microprocessor or microcontroller, whereby a data bus - preferably a serial data bus, for example a serial optical data bus - takes over the connection of the control device to the module locations.

p0017The last-mentioned measures lead in particular to the advantage that the module arrangement can be scaled very simply by adding further modules. The new modules must only be connected to the existing data bus.

p0018A further increase in the flexibility of the entire system is achieved when the control device comprises a recognition unit which recognizes a positioning of the modules within the module row, an allocation table being determined absolutely depending on the placement of the output modules and on the basis of a relative allocation table. This means that the allocation table initially contains an allocation of module positions within the module series relative to the output modules. For example, the relative allocation table could contain the assignment that all modules to the left of an output module are assigned to it, and all modules to the right of the last right output module are assigned to all output modules. On the basis of the assignment of the module locations within the module series with input and output modules, the control device can then determine an absolute allocation table, on the basis of the relative allocation table, in which the assignment is stored in absolute values, ie module 1 acts on module 4, etc.

p0019These measures lead to the greatest possible flexibility and freedom in the construction of a modular safety switchgear system, which is also very simple to scale. Preferably, an input unit is provided which allows input and / or modification of the allocation table, so that a further increase in the flexibility of the entire system is achieved.

p0020The input modules are input circuits of known safety switching devices, ie those circuits which reliably evaluate the signals from safety sensors. The output circuits are the output contacts of safety switching devices, ie electromechanically operating or electronically operating switches, which are actuated by the output signals of the input circuits. The output circuits are also securely constructed. It is known in this connection that a secure structure can be achieved, for example, by providing two independent channels or a channel plus checking unit.

p0021Further advantages and embodiments of the invention will be apparent from the description and the accompanying drawing.

p0022It is to be understood that the features mentioned above and those which are still to be explained below can be used not only in the particular combination indicated but also in other combinations or in a single setting without departing from the scope of the present invention.

p0023Exemplary embodiments of the invention are illustrated in the drawing and are explained in more detail in the following description. Show it:<dl id="dl0001"><dt>FIG</dt><dd>2 shows a schematic block diagram of a use according to the invention;</dd><dt>FIG</dt><dd>5 is a circuit diagram of a possible assignment of input modules and output modules;</dd><dt>FIG</dt><dd>4 is a schematic block diagram of a control device which is provided in a control module;</dd><dt>FIG</dt><dd>4 is a schematic perspective view of a safety switch module assembly according to the embodiment shown in FIG <figref idrefs="f0001">FIG</figref> Shown; </dd><dt>FIG</dt><dd>5 is a schematic representation of the rear side of the <figref idrefs="f0002">FIG</figref> Safety switch module assembly; and</dd><dt>FIG</dt><dd>6 is a schematic block diagram of a safety switch module assembly according to a further embodiment.</dd></dl>

p0024In <figref idrefs="f0001">FIG</figref> A safety switch module assembly is denoted by the reference numeral 10. This safety switch module assembly (hereinafter referred to briefly as a module arrangement) comprises a plurality of module locations 12.1 to 12.7 arranged in a row and each accommodating a module 14 in the present exemplary embodiment. In particular, the module location 12.1 contains a control module 16, the module locations 12.2, 12.3, 12.5 and 12.7 each comprise an input module 18.1 to 18.4, and the two module locations 12.4 and 12.6 each have an output module 19.1 and 19.2. The input and output modules thus form a module series, in which each module occupies a specific position or a specific module location.

p0025The input modules 18.1, 18.2, 18.3 and 18.4 are connected on the input side to signal generators, which is indicated by arrows P. For the signal generators used in<figref idrefs="f0001">FIG</figref> Are identified by the reference numeral 20, for example, protective door switches 20.1 or an emergency stop switch 20.2. In the present exemplary embodiment, the emergency stop switch 20.2 is assigned to the input module 18.4 and the other protective door switch 20.1 is assigned to the input modules 18.1, 18.2 and 18.3.

p0026The input modules 18 contain evaluation and control units, via which the signals from the safety sensors are reliably evaluated. The basic structure of such input modules is, for example, disclosed in "Machine safety", Winfried Gräf, Hüthig Verlag, 1997. Furthermore, the<patcit id="pcit0002" dnum="DE10011211"><text>Application DE 10011211</text></patcit> Of the present applicant, the construction of such input modules. Usually, these input modules are of two-channel design in order to achieve the required safety in the evaluation of the input signals.

p0027The two output modules 19.1 and 19.2 provided usually comprise electromechanical or electronic switching elements which reliably switch between two switching states, depending on the input signals fed. The output signal of the respective output module 19.1, 19.2 is fed to an actuator, which is indicated by arrows A. The actuators are, for example, contactors 21 which can produce or interrupt the power supply of a motor, for example.

p0028The function of the entire safety switch module arrangement is now to interrupt the power supply of the motors assigned to the two contactors when the emergency stop switch 20.2 is pressed while only one of the two motors is disconnected from the power supply if one of the protective door switches 20.1 Is actuated. The corresponding circuit diagram is shown in Fig<figref idrefs="f0001">FIG</figref> Respectively. The two contactors 21 are accordingly supplied with a respective current path, in each of which the emergency stop switch 20.2 and two protective door switches 2.1 or a protective door switch 20.1 are connected in series.

p0029A hierarchical design of the switches results because the emergency stop switch 20.2 acts on both contactors 21 while the protective door switches 20.1 each act only on one contactor 21.

p0030With regard to the <figref idrefs="f0001">FIG</figref> It is necessary for the output signals of the input modules 18.1, 18.2 and 18.4 to act on the output module 19.1 and the output signals of the input modules 18.3 and 18.4 on the output module 19.2, <figref idrefs="f0001">FIG</figref> Specified link. The above assignment of the input modules to the output modules is graphically represented by means of arrows Z. This assignment, indicated by arrows Z, requires electrical signal lines which connect output terminals of the input modules to input terminals of the output modules. Possible implementations of such electrical connections are explained in more detail in the further course of the description.

p0031The control module 16 comprises a control device 30 in which the desired assignment of module locations 12 for input modules to module locations 12 for output modules is retained. For example, an allocation table that defines the assignment identified by the arrows Z could be as follows:<tables id="tabl0001" num="0001"><table frame="all"><tgroup cols="5"><colspec colnum="1" colname="col1" colwidth="18mm" /><colspec colnum="2" colname="col2" colwidth="12mm" /><colspec colnum="3" colname="col3" colwidth="12mm" /><colspec colnum="4" colname="col4" colwidth="12mm" /><colspec colnum="5" colname="col5" colwidth="12mm" /><thead><row><entry valign="top">entrance</entry><entry align="center" valign="top" /><entry align="center" valign="top" /><entry align="center" valign="top" /><entry align="center" valign="top" /></row><row><entry valign="top">exit</entry><entry align="center" valign="top">12.2</entry><entry align="center" valign="top">12.3</entry><entry align="center" valign="top">12.5</entry><entry align="center" valign="top">12.7</entry></row></thead><tbody><row><entry align="char" char="." charoff="21">12.4</entry><entry align="center">V</entry><entry align="center">V</entry><entry align="center">-</entry><entry align="center">V</entry></row><row><entry align="char" char="." charoff="21">12.6</entry><entry align="center" /><entry align="center" /><entry align="center">V</entry><entry align="center">V</entry></row></tbody></tgroup></table></tables>

p0032In this table, "V" stands for a signal connection, ie, a connection for transmitting signals is present, for example, between the module location 12.2 and the module location 12.4 provided for an output module. In accordance with the indicated assignment table, a safety switching device system can thus be constructed, in which two actuators can be controlled independently of one another via the output modules 12.4 and 12.6, the output module in the module location 12.4 being connected via a maximum of three AND-linked signal transmitters and the output module in module location 12.6 via a maximum of two AND-linked safety devices.

p0033Of course, it is quite conceivable not to occupy individual module locations for input modules, so that, in the simplest case, only the module location 12.7 is equipped with an input module 18.4, with the result that both contactors 21 can be actuated by the emergency stop switch 20.2 alone .

p0034The particularity of the present module arrangement 10 is in particular to be seen in the fact that the assignment of module positions 12.2, 12.3, 12.5 and 12.7 for input modules 18.1 to 18.4 to module positions 12.4 and 12.6 for output modules 19.1, 19.2 is provided independently of the actually used input modules 18. The user can thus assemble a system in a modular manner, whereby only the predefined assignment table restricts the number of different linking possibilities. If, for example, the user wishes to actuate a contactor 21 via two safety actuators connected in series, he selects the module locations 12.2 and 12.3 for the input modules and the output module 19.1 in the module location 12.4 for activating the corresponding contactor 21. If, however, the user wishes to establish a hierarchical system in which Two contactors 21 can be actuated via a central emergency stop switch 20.2 and in each case via a door switch 20.1, it selects the module locations 12.3 and 12.5 for each input module and the module location 12.7 for an input module 18.4 assigned to the emergency stop switch Output modules 19.1, 19.2 are provided in the module locations 12.4 and 12.6.

p0035Thus, it can be seen that very different safety switchgear systems can be installed, whereby different series circuits and parallel circuits of safety sensors are conceivable. Of course, the<figref idrefs="f0001">FIG</figref> Can be scaled, ie can be expanded to more than the four input modules shown and two output modules.

p0036In the aforementioned exemplary embodiment, the module locations for the output modules 19.1 and 19.2 were defined on the module locations 12.4 and 12.6. Of course, it is also conceivable to construct the module arrangement such that the module locations for the output modules 19.1 and 19.2 can also be freely selected. In this case, however, the abovementioned absolute allocation table must be abandoned and instead a relative allocation table must be stored in the control device 30. "Relative" means that the allocation of the module locations relative to the position of the output modules used is specified in the module series. An implementation of the abovementioned absolute table into a relative allocation table would be expressed by words, for example:<ol><li>A) All modules to the left of the first output module 19.1 are allocated to this module</li><li>B) all module locations between the first and second output modules 19.1, 19.2 are assigned to the second output module 19.2</li><li>C) all modules to the right of the second output module 19.2 are assigned to both output modules 19.1, 19.2.</li></ol>

p0037In mathematical form, this assignment might look as follows:<ol><li>A) MP <MP-A1 → A1</li><li>B) MP-A1 <MP <MP-A2 → A2</li><li>C) MP> MP-A2 → A1 and A2</li></ol>

p0038Where MP is the module slot number and MP-A1 is the module slot number of the output module A1 and MP-A2 is the module slot number of the output module A2.

p0039From this relative allocation table, an absolute allocation table as shown above can be calculated as soon as the two output modules 19.1 and 19.2 are attached to corresponding module locations. At the start of the system, the control device 30 determines those module locations in which output modules are arranged and then calculates the absolute allocation table by means of this. In order to enable recognition of output modules and input modules for the control devices 30, each module 18, 19 has an identifier by means of which the control device can determine the type of the module. Furthermore, the control device determines the number of the module location within the module row in which the respective input or output module is accommodated. Thus, in the control device, an exact image of all module locations and thus of the entire module series with the inserted input or output modules is provided. This information together with the calculated absolute allocation table allows the control module 16 to forward the output signals of the input modules 18.1 to 18.4 to the assigned output module according to the logic rule specified in the allocation table.

p0040It can be seen that this system, which does not include fixed module positions for output modules, is much more flexible. For example, it would be conceivable to provide the two output modules 19.1 and 19.2 at the module locations 12.3 and 12.5, respectively, and the input module 18.2 and 18.3 at the module locations 12.4 and 12.6. This would then result in the above-mentioned relative allocation table that the emergency stop switch 20.2 would be AND-linked with a protective door switch 20.1 and actuate both contactors 21 with the emergency stop switch 20.2 as well as with the protective door switch 20.1. Both motors could thus be stopped by opening the corresponding protection door or the emergency stop switch.

p0041In <figref idrefs="f0001">FIG</figref> The control device 30 of the control module 16 is illustrated as a block diagram. The control device 30 comprises a control unit 31, which is designed, for example, as a microprocessor. A memory 33 with random access (RAM) and a read-only memory 35 (ROM, EEPROM, etc.) are connected to the control unit 31 via corresponding lines. Furthermore, the control device 30 comprises an input unit 37, which allows the input and modification of data which are stored in the RAM memory 33. A bus module 38 is provided for controlling the communication via a data bus and a signal bus (not shown). In the simplest case, the bus is implemented as a shift register, in which each module is a cell of the shift register, the content of which is shifted to the control unit or the bus module 38 via clock signals.

p0042As previously mentioned, the controller 30 includes a relative allocation table. This is stored in the ROM 35 so that it is not lost even in case of power failure. In contrast, the absolute allocation table calculated by the control unit 31 is stored in the RAM memory 33. In addition, the control unit 31 controls the module recognition process, in which, in sequence, each module location 12.2 to 12.7 is then interrogated, whether a module is plugged in and which type (input or output module, type of module, for example, which type of safety device is) Connected, etc.) is this module.

p0043In <figref idrefs="f0002">FIG</figref> The module arrangement 10 is shown in a perspective view. This module arrangement 10 comprises a schematically illustrated housing 40 in which individual module locations 12.1 to 12.7 are physically provided. The assembly of the module locations 12.1 to 12.7 corresponds to that in FIG<figref idrefs="f0001">FIG</figref> Shown in detail there, so that no further description is given.

p0044The individual modules 18, 19 can be inserted in a simple manner from the front into the respective module location 12, as is graphically illustrated in the output module 19.2. Plug contacts are provided on the rear side of the modules, which engage in corresponding plug-in contact receptacles. These plug-in contact receptacles are provided on a printed circuit board 50, which extends over the entire width at the rear side of the housing 40. In the<figref idrefs="f0002">FIG</figref> This circuit board 50 can be seen. Furthermore, the plug contact receptacles at each module location 12 are schematically indicated and are identified by the reference numeral 52. The lines required for supplying the individual modules, but in particular the data and signal bus, run on the printed circuit board 50, wherein for the sake of illustration, a few individual lines are shown and are designated by the reference numeral 53.

p0045It results from <figref idrefs="f0002">FIG</figref>That the module arrangement 10 in a simple manner allows the construction of a hierarchical switchgear system. In particular, the system can be easily modified as required and thus adapted to new circumstances. Moreover, the aforesaid relative allocation table provides a very simple way to assign different input modules differently to different output modules. It is no longer necessary to change the wiring of the input and output modules.

p0046One opposite the <figref idrefs="f0002">FIG</figref> , A more flexible solution for accommodating modules is to provide a so-called DIN rail within a switch cabinet, on which the modules can be mounted as desired. As a result, there are no longer any fixedly predetermined module locations, which means that the individual modules can be connected to one another by means of fixed wiring, for example,<figref idrefs="f0002">FIG</figref> Is not possible. Instead, the modules are interconnected via a serial synchronous bus system, one module being connected to the adjacent modules via corresponding signal lines. The assignment of the input modules to the output modules in this case takes place via the already mentioned relative allocation table, which is stored in the control module 16. Via the data bus, the control module 16 is able to recognize the module locations or the module positions of the input modules and of the output modules within the module series and, as explained above, to calculate the absolute allocation table.

p0047Consequently, it does not matter whether the input modules or the output modules are installed in defined module locations or, for example, arbitrarily on a DIN rail within a switch cabinet.

p0048In <figref idrefs="f0003">FIG</figref> A section of a module arrangement 10 'is shown, which does not differ in terms of its functionality from the module arrangement 10 already explained. The difference between this module arrangement 10 'and the already explained module 10 is the type of data transmission or signal transmission from one module to the other.

p0049Compared to the described wire-bound bus solution, the module arrangement 10 'according to FIG <figref idrefs="f0003">FIG</figref> A transmission of the data by optical means. For this purpose, the input modules 18 as well as the output modules 19 each have two transmitting / receiving units 80, 82. The control module 16, on the other hand, comprises only a transmitting / receiving unit 84.

p0050The two transmitting / receiving units 80 comprise three receiving elements 86 as well as a transmitting element 88. In contrast, the transmitting / receiving units 82 and 84 comprise three transmitting elements 88 and a receiving element 86.

p0051Each of the receiving elements 86 comprises an infrared sensor 91 and an amplifier stage 93 which amplifies the output signal of the infrared sensor 91.

p0052Each transmitting element 88 comprises an infrared transmitter, preferably in the form of an infrared LED 95, and a driver stage 97, which serves to drive the LED 95.

p0053In the present exemplary embodiment, the transmitting / receiving units 80 are arranged on the left within the input and output modules while the transmitting / receiving units 82 are arranged in the modules on the right. The same also applies to the transmitting / receiving unit 84 in the control module 16. In order to allow a transfer of data from one module to the adjacent module, openings for the infrared transmitters and infrared receivers are provided in the side walls of the modules. If the modules are arranged in a module row side wall on the side wall, a transmitting / receiving unit 80 of a module is located opposite a transmitting / receiving unit 82 or 84, respectively, of the adjacent module so that an optical connection is established between the infrared receivers and the infrared transmitters. By means of a corresponding module-internal connection of the transmitting / receiving unit 80 to the transmitting / receiving unit 82, a bus system can thus be constructed within the module row.

p0054For data transmission via the optical data bus from and to the control device 30, it is necessary that each module 18 and 19 has corresponding registers for storing data. In the present exemplary embodiment, the input module 18.1 comprises an input shift register 61 which stores a signal from the connected safety sensor 20.

p0055The output module 19 also includes an input shift register 61 and an output shift register 63 in which a signal for controlling the contactor 21 is stored.

p0056The individual shift registers 61, 63 of the input and output modules arranged in the module row form a shift register, which is controlled by the control device 30. The control device 30 can transmit a clock signal via an output 65 to the modules 18, 19 which ensures that a data stored in a shift register 61, 63 is shifted to the next shift register in the direction of the control device 30. Via an output 67 of the control device 30, a transfer signal can be transmitted to the modules 18, 19, which ensures that a signal applied to the respective shift register is stored.

p0057Furthermore, the control device 30 comprises a data output 68, via which data are transmitted to the modules 18, 19 and a data input 69 to which the data located in the shifting registers are fed. Thus, the present bus system comprises two control lines which are connected to the outputs 65 and 67 of the control device 30, as well as two data lines which are connected to the output 68 and the input 69, respectively. In order to enable a connection of the two data lines at the end of the module row, a coupling element 71 in the form of a light guide is installed in the present case.

p0058The energy supply for the individual modules 18, 19 is effected via a power supply unit 73, which is provided in the control module 16, from which two supply lines 74 originate. Each of the modules 16, 18, 19 has corresponding plug-in contacts 76 for passing the supply lines 74 through all the modules and thus ensuring the corresponding supply.

p0059As already described in connection with the first exemplary embodiments, each module 18, 19 has an identifier which is fed to the control module. The respective identifier is solved in a module 18, 19 by a hardware, for example by a resistor circuit. In<figref idrefs="f0003">FIG</figref> The arrows K indicate that the respective identification information is fed to the two input shift registers 61 which is passed on to the control module via the bus.

p0060It is to be understood that the embodiments shown in FIGS <figref idrefs="f0001">FIG</figref> and <figref idrefs="f0003">6</figref> Are purely illustrative in nature and do not limit the scope of the invention. Rather, other embodiments are quite conceivable. Thus, for example, it is possible to save the control module 16 and realize the link table in the form of a fixed wiring of the individual module locations 12. It is clear that this solution has limited flexibility compared to the previously described embodiment. However, it is sufficient for many applications.

p0061Also the <figref idrefs="f0002">FIG</figref> Can be realized in a different manner, which is common to the average person skilled in the art.