SYSTEM HAVING A CONTROLLER AND HAVING AN ACTUATOR AND ALSO HAVING AN ASSEMBLY FOR PROVIDING FUNCTIONAL SAFETY

Abstract

A system with a controller and with an actuator as well as with an assembly for providing functional safety. The assembly has a switching unit, which is inserted into an electrical supply line of the actuator and is operated via a control device of the assembly, which is connected to the controller in terms of signal technology. The invention further relates to an assembly and a switching unit.

Claims

1. A system comprising: a controller; an actuator; and an assembly for providing functional safety, the assembly having a switch, which is inserted into an electrical supply line of the actuator and is operated via a control device of the assembly, which is connected to the controller in terms of signal technology.

2. The system according to claim 1, wherein the switch has a number of switching elements, which are electrically connected in series and are inserted into the supply line.

3. The system according to claim 2, wherein two of the switching elements are each a mechanical switch.

4. The system according to claim 2, wherein one of the switching elements is a semiconductor switch.

5. The system according to claim 1, wherein the switch has a fuse, which is electrically connected in series with the switching elements.

6. The system according to claim 2, wherein the switch has a control unit, via which the switching elements are actuated.

7. The system according to claim 1, wherein the switch has an additional switching element, which is inserted into a ground line of the actuator.

8. The system according to claim 1, further comprising a further actuator with a further supply line, the switch having a number of further switching elements, which are electrically connected in series and are inserted into the further supply line or the assembly having a further switching unit, which is inserted into the further supply line and is operated via the control device.

9. The system according to claim 1, wherein the control device and the switch are connected via a first bus system in terms of signal technology, the control device being configured as a master of the first bus system.

10. The system according to claim 1, wherein the control device and the controller are connected via a second bus system in terms of signal technology, the control device being configured as a slave of the second bus system.

11. An assembly for providing functional safety according to claim 1.

12. A switching unit according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein:

[0041] FIG. 1 shows a schematic sketch of a system with a controller and with an actuator as well as with an assembly,

[0042] FIG. 2 shows the system according to FIG. 1, with a further actuator and a modified switching unit of the assembly, and

[0043] FIG. 3 shows the system according to FIG. 2, with a further switching unit.

DETAILED DESCRIPTION

[0044] FIG. 1 shows a schematic sketch of a system 2, which is a component of an industrial plant not shown in more detail. The system 2 has an actuator 4 in the form of an electromechanical valve, via which a flow of a fluid, such as a gas or a liquid, through a pipe is controlled. The actuator 4 has a supply line 8 and a ground line 10, which are electrically contacted with a supply network 12. In this example, the supply network 12 is provided via a rectifier not shown in more detail. The ground line 10 is also electrically connected to ground 14. A constant electrical potential is guided via the supply line 8 and the ground line 10, with an electrical voltage of 200 V being applied between them.

[0045] Furthermore, the system 2 has a controller 16, in which process parameters for actuating the actuator 4 are stored, so that a suitable control/regulation of the fluid supply takes place. The controller 16 is a programmable logic controller and via this a control and/or regulation of further components of the industrial plant not shown in more detail, such as of further machines and/or actuators, which are not shown in more detail here, takes place.

[0046] Furthermore, the system 2 has an assembly 18, which serves to provide functional safety. The assembly 18 has a power supply 20, a control device 22 and a switching unit 24, which are each designed as assemblies that can be lined up together and are arranged in a control cabinet, which is not shown in more detail. The switching unit 24 is designed as a separate component, which can be detached from the control device 22 for assembly and/or replacement purposes. The power supply 20 has a power source 26, via which a DC electrical voltage of 24 V is provided. The power source 26 is guided against two power connections 28 of the power supply 20, which are electrically connected to respective corresponding power connections 28 of the control device 22 and of the switching unit 24, so that an electrical supply is provided to the control device 22 and to the switching unit 24 via the power supply 20.

[0047] The control device 22 has a control module 30, which is electrically supplied via the power connection 28. Furthermore, the control module 30 is connected to the controller 16 in terms of signal technology via two second connections 32 of the control device 22, each via a second bus line 34 of a second bus system 36. Due to the two second bus lines 34 and the two second connections 32, redundancy is provided. The second bus system 36 complies with the Profisafe or Safety over 10 Link standard, and the controller 16 is configured as the master of the second bus system 36. The control device 22, in particular the control module 30, is configured as a slave of the second bus system 36. If a plurality of such assemblies 18 are present, each control device 22 is configured as a respective slave of the second bus system 36.

[0048] To provide fail-safety, the control module 30 has two subsections 38, which carry out the same functions, but are provided via mutually different circuitry. In other words, the control module 30 also is of redundant design. The control module 30 is connected to corresponding connections 46 of the switching unit 24 via two first connections 40, each via a first bus line 42 of a first bus system 44 assigned there. Thus, a redundant signal connection between the control device 22 and the switching unit 24 is also implemented here. A control unit 48, which has two parts 50, is connected to the connections 46 in terms of signal technology. The two parts 50 carry out the same functions during operation, so that the control unit 48 also has a redundant structure. Power is supplied to the control unit 48 via the power connections 28.

[0049] In summary, the control device 22, namely the control module 30, and the switching unit 24, namely the control unit 48, are connected via the first bus system 44 in terms of signal technology, which is operated in accordance with the Profisafe or Safety over 10 Link standard. In this case, the control device 22 is configured as a master and the switching unit 24 is configured as a slave of the first bus system 44. In other words, communication in the first bus system 44 is specified via the control device 22. The first bus system 44 is in this case independent of the second bus system 36, and the switching unit 24 is not assigned an address in the second bus system 36.

[0050] The switching unit 24 has a strand 52, which is inserted into the supply line 8. In other words, during operation via the strand 52, part of the electrical energy is conducted from the supply network 12 to the actuator 4, and the switching unit 24 is inserted into the supply line 8. The strand 52 has a total of three switching elements 54, which are electrically connected in series. Two of the switching elements 54 are configured as a mechanical switch 56. The mechanical switch 56 is a contactor. The remaining switching element 54 is a semiconductor switch 58 in the form of a MOSFET. The semiconductor switch 58 also acts as a current li-miter. When an electric current of 10 A is exceeded, the ohmic resistance of the semiconductor switch 58 increases, so that the electric current cannot further increase. Thus, via the semiconductor switch 58, a protection of the actuator 4 as well as of other components of the switching unit 24 takes place. In summary, the switching elements 54 are inserted into the supply line 8 and are electrically connected in series.

[0051] The switching elements 54 are actuated via the control unit 48. For this purpose, a respective electrical supply voltage is applied to the switching elements 54 via the control unit 48, so that they are in the electrically conductive or electrically non-conductive state. Moreover, the switching elements 54 are designed in such a way that, by applying an electrical voltage to them, it can be queried as to which switching state they are in. The state of the switching elements 54 is also interrogated via the control unit 48.

[0052] Furthermore, a fuse 60 is inserted into the strand 52, which fuse 60 is thus electrically connected in series with the switching elements 54. The fuse 60 is configured as a glass tube fuse. The fuse 60 serves as a final protection in case, for example, a fault occurs in the control unit 48, the semiconductor switch 58, which acts as a current limiter, or other components of the switching unit 24. When the fuse 60 is tripped, it is destroyed and thus the strand 52 is disconnected. As a result, an electrical power supply to the actuator 4 from the supply network 12 is interrupted.

[0053] The ground line 10 also runs through the switching unit 24, which is thus inserted into the ground line 10 of the actuator 4. An additional switching element 62, which in this example is designed as a mechanical switch, namely as a contactor, is inserted into the ground line 10, so that this can also be interrupted. The additional switching element 62 is also actuated via the control unit 48, wherein, moreover, the state of the additional switching element 62 can be interrogated.

[0054] During operation, a request for actuation of the actuator 4 is transmitted from the controller 16 via the second bus system 36 to the control device 22 of the assembly 18. For this purpose, a safe protocol is used, and the request is generated based on the execution of a safe function, namely STO (“safe torque off”), for example. The request is processed via the control module 30 and first verified. Subsequently, it is derived therefrom which of the switching elements 54 is to be actuated. It is also verified whether the additional switching element 62 is to be actuated. When the actuator 4 is to be disconnected from the supply network 12, the command is transmitted via the second bus system to the control unit 48 to actuate first the semiconductor switch 58 and subsequently after that the mechanical switches 56 of the strand 52. Following this, the additional switching element 62 is to be actuated. The corresponding request is received via the control unit 48 and verified by the latter. Following this, the semiconductor switch 58 is first transferred to the electrically non-conductive state via suitable application of an electrical voltage thereto. When this is done, the mechanical switch 56 is opened via the control unit 48, for which purpose a suitable electrical voltage is applied thereto. Following this, the additional switching element 62 is actuated and thus the ground line 10 is also disconnected. As a result, the actuator 4 is completely galvanically isolated from the supply network 12. Due to the sequence, no electric arc is generated at the mechanical switches 56 and also at the additional switching element 62, which is why a comparatively large number of switching operations can be carried out.

[0055] If the process parameters specify that the actuator 4 is energized, a corresponding request is transmitted to the control device 22 via the controller 16. There, the request is first verified, and following this, via the control module 30, the request is transmitted to the control unit 48 to first close the additional switching element 62 and subsequently to close the mechanical switch 56. Following this, the semiconductor switch 58 is to be transferred to the electrically conductive state. Thus, also in this case, the formation of an arc is prevented, and following this the actuator 4 is electrically contacted with the supply network 12. Thus, the switching unit 24 is operated via the control device 22.

[0056] Furthermore, the switching unit 24 has sensors not shown in more detail, via which the electrical current conducted via the strand 52 and the electrical potential conducted therewith are monitored. The sensors are read out via the control unit 48 and are, for example, integrated into the switching elements 54 or at least one of the switching elements 54 or are a separate component. If the electric current and/or the electric potential and/or a respective change thereof is greater than a certain limit value, at least one of the switching elements 54, in particular all of the switching elements 54, is actuated via the control unit 48, so that they are transferred to the electrically non-conductive state. Thus, the switching unit 24 also acts as a circuit breaker.

[0057] Since the control module 30, the bus systems 36, 44 and the control device unit have a redundant design and a plurality of switching elements 54 are present, the assembly 18 fulfills a certain safety level, wherein the individual components of the assembly 18 are matched to each other. During assembly, only a comparatively small amount of cabling is required.

[0058] In a variant of the system 2 shown in FIG. 1, which is not shown in more detail, the semiconductor switch 58 and/or the fuse 60 are not present.

[0059] FIG. 2 shows a modification of the assembly 18, in which only the switching unit 24 is modified. The switching unit 24 has a further strand 64, which is identical in construction to the strand 52. Thus, the further strand 64 has three further switching elements 66, one of which corresponds to each of the switching elements 54, and which are electrically connected to each other accordingly. The further switching elements 66, two of which are mechanical switches and one of which is a semiconductor switch in the form of a MOSFET, are also actuated via the control unit 48, and via the control unit 48 a state of the further switching elements 66 during operation is also read out. Further, a further fuse 68 is provided in the further strand 64, which carry out the same function in the further strand 64 as the fuse 60 in the strand 52.

[0060] The further strand 64 is inserted into a further supply line 70 of a further actuator 72. The further actuator 72 further has a further ground line 74, into which the switching unit 24 is also inserted. Thus, the switching unit 24 has a further additional switching element 76 corresponding to the additional switching element 62. The further ground line 74 is guided against ground 14 and is suitably contacted with the ground line 10 for this purpose. In this case, the further additional switching element 76 is arranged between the further actuator 72 and the electrical connection with the ground line 10.

[0061] During operation, the further switching elements 66 and the further additional switching element 76 are also actuated via the control unit 48 in dependence of requests/commands specified on the part of the controller 16. The electrical current/the respective electrical potential applied via the further line 64 and the further ground line 74 is also monitored.

[0062] In a variant of the system 2 shown in FIG. 2, which is not shown in more detail, the further fuse 68 is not present. Also, for example, the further strand 64 is free from semiconductor switches, with the strand 52 having the semiconductor switch 58. In a further alternative, the strand 52 also does not have the semiconductor switch 58.

[0063] FIG. 3 shows a further variation of system 2, where the assembly 18 is based on the embodiment shown in FIG. 1. Thus, the switching unit 24 and the power supply 20 are unchanged. However, just as in the embodiment shown in FIG. 2, the further actuator 72 is present, which has the further ground line 74 as well as the further supply line 70. Additionally, there is a further switching unit 78, which is constructed in the same way as the switching unit 24. However, the further switching unit 78 is inserted into the further supply line 70 as well as the further ground line 74. The switching unit 24 is only inserted into the supply line 8 as well as the ground line 10. Thus, one of the switching units 24, 78 is assigned to each of the actuators 4, 72.

[0064] The further switching unit 78 is also electrically connected to the power source 26 of the assembly 18 and is thus supplied with electrical energy via the power supply 20. The first bus system 44 is also extended, so that both switching units 24, 78 are now connected to the control device 22 in terms of signal techno-logy. In this case, the two switching units 24, 78 are each configured as a slave.

[0065] If a request/command to change the operation of the actuators 4, 72 is created via the control device 22, this is received via the control device 22 and verified there. Following this, the control module 30 determines, which of the switching units 24, 78 is to be actuated. Depending on this, a corresponding command, as already described for FIG. 1, is fed to the respective control unit 48 in the first bus system 44. Thus, both switching units 78 are actuated by means 24,of the control device 22.

[0066] The invention is not limited to the embodiments described above. Rather, other variants of the invention can also be derived therefrom by expert without leaving the object of the invention. Furthermore, in particular, all individual features described in connection with the individual embodiment examples can also be combined with each other in other ways without leaving the object of the invention.