RELAY MODULE

Abstract

The disclosure relates to an electromagnetic relay module, comprising a first circuit branch comprising a first capacitor and a first relay connected in series with the first capacitor, a second circuit branch comprising a second capacitor and a second relay connected in series with the second capacitor, a switching element which is arranged between the first circuit branch and the second circuit branch and comprises a first switching state and a second switching state. In the first switching state of the switching element the first circuit branch and the second circuit branch are arranged in a parallel connection. In the second switching state of the switching element the first relay and the second relay are arranged in a series connection. The switching element is configured to change from the first switching state to the second switching state in the switch-on process of the relay module

Claims

1. An electromagnetic relay module, comprising: a first circuit branch comprising a first capacitor and a first relay connected in series with the first capacitor, a second circuit branch comprising a second capacitor and a second relay connected in series with the second capacitor, a switching element which is arranged between the first circuit branch and the second circuit branch and comprises a first switching state and a second switching state, wherein in the first switching state of the switching element the first circuit branch and the second circuit branch are arranged in a parallel connection, and wherein in the second switching state of the switching element the first relay and the second relay are arranged in a series connection, and wherein the switching element is configured to change from the first switching state to the second switching state in the switch-on process of the electromagnetic relay module.

2. The electromagnetic relay module of claim 1, wherein the electromagnetic relay module comprises a holding position in which a first armature is attracted by the first relay and in which a second armature is attracted by the second relay, and wherein the switching element is configured to change from the first switching state to the second switching state as soon as the electromagnetic relay module has taken a stop position.

3. The electromagnetic relay module of claim 2, wherein the first capacitor is configured to provide a first charging current to the first relay in the first switching state of the switching element, and the second capacitor is configured to provide a second charging current to the second relay in the first switching state of the switching element, the first charging current being suitable for causing an attraction and holding of the first armature, and wherein the second charging current is suitable to cause an attraction and holding of the second armature.

4. The electromagnetic relay module of claim 3, wherein the electromagnetic relay module is connected to a voltage source which is configured to provide a constant voltage, wherein the first circuit branch and the second circuit branch is connected to the voltage source.

5. The electromagnetic relay module claim 4, wherein the first capacitor provides the first charging current and the second capacitor provides the second charging current, when the constant voltage is applied to the first circuit branch and to the second circuit branch.

6. The electromagnetic relay module of claim 1, wherein the first switching state of the switching element comprises a higher resistance of the switching element compared to a resistance of the switching element in the second switching state and wherein the second switching state of the switching element comprises a lower resistance of the switching element compared to a resistance of the switching element in the first switching state.

7. The electromagnetic relay module of claim 6, wherein the switching element comprises a diode, wherein the diode is configured to transition from the first switching state to the second switching state upon reaching a forward voltage of the diode.

8. The electromagnetic relay module of claim 7, wherein the switching element comprises a second diode, a series resistor, or a combination thereof.

9. The electromagnetic relay module of claim 6, wherein the switching element comprises a transistor, and wherein the transistor comprises a bipolar transistor or a metal-oxide-silicon field-effect transistor (MOSFET).

10. The electromagnetic relay module of claim 9, wherein the transistor is preceded by an RC element and a voltage divider, by which a time constant is defined.

11. The electromagnetic relay module of claim 9, wherein the transistor is preceded by a controller which is configured to determine a switching time of the transistor as a function of a measured current in the first circuit branch or the second circuit branch.

12. The electromagnetic relay module of claim 11, wherein the controller is configured to provide a switching voltage for switching the switching element when the measured current falls below a predetermined limit value.

13. The electromagnetic relay module of claim 12, wherein a first blocking diode is arranged between the first relay and the switching element to block a flow of current from the switching element to the first relay and a second blocking diode is arranged between the second relay and the switching element to block a flow of current from the second relay to the switching element.

14. The electromagnetic relay module of claim 1, wherein the electromagnetic relay module is a safety relay module configured to fulfill a safety-relevant function and wherein the first relay and the second relay are redundant relays.

15. The electromagnetic relay module of claims 1, wherein the electromagnetic relay module is included in an emergency stop switch or a protective door switch or a magnetic switch or with a light curtain.

16. The electromagnetic relay module of claim 11, wherein the controller comprises a microcontroller.

17. The electromagnetic relay module of claim 1, wherein the electromagnetic relay module comprises a holding position in which an armature is attracted by the first relay, wherein the switching element is configured to change from the first switching state to the second switching state as soon as the electromagnetic relay module has taken a stop position.

18. The electromagnetic relay module of claim 17, wherein the first capacitor is configured to provide a charging current to the first relay in the first switching state of the switching element, the charging current being suitable for causing an attraction and holding of the armature.

19. The electromagnetic relay module of claim 1, wherein the electromagnetic relay module comprises a holding position in which an armature is attracted by the second relay, wherein the switching element is configured to change from the first switching state to the second switching state as soon as the electromagnetic relay module has taken a stop position.

20. The electromagnetic relay module of claim 19, wherein the second capacitor is configured to provide a charging current to the second relay in the first switching state of the switching element, the charging current suitable to cause an attraction and holding of the armature.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Further examples of the principles described herein are explained with reference to the accompanying figures.

[0050] FIG. 1 shows an equivalent circuit diagram of a relay module according to an example of the disclosure;

[0051] FIG. 2 shows an equivalent circuit diagram of a relay module in accordance with a further example of the disclosure;

[0052] FIG. 3 shows an equivalent circuit diagram of a relay module according to a further example of the disclosure;

[0053] FIG. 4 shows an equivalent circuit diagram of a relay module according to a further example of the disclosure;

[0054] FIG. 5 shows an equivalent circuit diagram of a relay module according to a further example of the disclosure;

[0055] FIG. 6 shows an equivalent circuit diagram of a relay module according to a further example of the disclosure; and

[0056] FIG. 7 shows a schematic illustration of an arrangement with a relay mode according to an example of the disclosure.

DETAILED DESCRIPTION

[0057] In the following detailed description, reference is made to the accompanying drawings, which form a part hereof, and in which there is shown, by way of illustration, specific examples in which the disclosure may be carried out. It goes without saying that other examples can also be used and structural or logical changes can be made without deviating from the concept of the present disclosure. The following detailed description is therefore not to be taken in a limiting sense. Furthermore, it is understood that the features of the various examples described herein can be combined with one another, unless specifically stated otherwise.

[0058] The aspects and examples are described with reference to the drawings, wherein like reference characters generally refer to like elements.

[0059] FIG. 1 shows an equivalent circuit diagram of a relay module 100 according to an example. The electromagnetic relay module 100 comprises a first relay 103 and a second relay 105. The first relay 103 comprises a first internal resistance 107 and a first coil 109. The first coil 109 is configured to generate a first magnetic field and to attract a first armature (not shown in the figures) by the first magnetic field. The second relay 105 comprises a second internal resistance 111 and a second coil 113. The second coil 113 is configured to generate a second magnetic field and to attract a second armature (also not shown in the figures) by the second magnetic field

[0060] If the first armature is attracted, the first relay 103 is in a holding state. If the second armature is attracted, the second relay 105 is in a holding state. If the first armature and the second armature are both attracted at the same time, the relay module 100 is in a holding state.

[0061] The relay module 100 has a first capacitor 115 and a second capacitor 117. The first capacitor 115 is connected in series with the first relay 103. The first capacitor 115 and the first relay 103 are arranged in a first circuit branch 119. The second capacitor 117 is connected in series with the second relay 105. The second capacitor 117 and the second relay 105 are arranged in a second circuit branch 121. The first circuit branch 119 and the second circuit branch 121 are arranged parallel to one another.

[0062] The relay module 100 comprises a voltage source 123. The voltage source 123 is a constant voltage source and is configured to output a constant voltage. This means that the voltage is regulated to a target value if fluctuations occur in the voltage provided. For example, the voltage source 123 provides a constant voltage of 12V. In a further example, the voltage source 119 provides another constant voltage, for example 24V. The first voltage branch 119 and the second voltage branch 121 are electrically connected to the voltage source 123.

[0063] By applying the constant voltage by the voltage source 123, the first capacitor 115 and the second capacitor 117 are charged. By charging the first capacitor 115, a first charging current flows through the first relay 103. By charging the second capacitor 115, a second charging current flows through the second relay 103.

[0064] The first capacitor 115 is dimensioned such that the first charging current is suitable for causing a magnetic flow through the first coil and thus a corresponding magnetic field that is suitable for fully attracting the first armature of the first relay 103 and thus to move the first relay 103 into the holding position. The second capacitor 115 is dimensioned such that the second charging current is suitable for causing a magnetic flow through the second coil and thus a corresponding magnetic field which is suitable for fully attracting the second armature of the second relay 103 and thus to move the second relay 103 into the holding position. Both capacitors 115, 117 are dimensioned so that the charging current is sufficient to achieve an initial flow in the coils 109, 113 used, which in each case generates a magnetic field to attract the corresponding armature.

[0065] The relay module 100 comprises a switching element 125. The switching element 125 is arranged between the first circuit branch 119 and the second circuit branch 121 such that the switching element 125 is arranged between the first relay 103 and the first capacitor 115 and between the second capacitor 119 and the second relay 105. The switching element 125 has a first switching state and a second switching state.

[0066] In the first switching state of the switching element 125, the switching element 125 is open or has a high resistance to prevent a current flow from the first relay 103 to the second relay 105 through the switching element 125. Preventing can be understood to mean that the flow of current is interrupted or limited to such an extent that it is negligible in the context of the usual application of the relay module 100. In the second switching state of the switching element 125, the first circuit branch 119 is electrically connected to the second circuit branch 121 by the switching element 125, so that an electrical current can flow through the switching element 125. The switching element 125 is closed here or has a low resistance.

[0067] When the switching element 125 is switched to the second switching state, the parallel connection of the first and second circuit branches 101, 102 is switched into a series connection of the first and second relay 103, 105. That is, by the switching element 125, the first relay 103 and the second relay 105 are electrically connected in series in the second switching state of the switching element 125. The switching element 125 is configured to switch from the first switching state to the second switching state when the relay module 100 reaches the holding state, that is, as soon as the first armature and the second armature are attracted.

[0068] The first capacitor 115 and the second capacitor 117 are high-resistive at the time of switching the switching element 125 and are not part of the series connection of the first relay 103 and the second relay 105. Thus, they ensure that a primary current path runs along the series connection of the first relay 103 and the second relay 105.

[0069] When the parallel connection of the first and second circuit branches 101, 102 is switched over to the series connection of the first relay 103 and the second relay 105, the total resistance of the first relay 103 and the second relay 105 is increased. This results in a reduction in the coil currents at constant voltage, which is ensured by the voltage source, and an associated reduction in the magnetic flow and the magnetic fields of the first relay 103 and the second relay 105, whereby the power dissipation of the relay module 100 can be reduced.

[0070] FIG. 2 shows an equivalent circuit diagram of a relay module 200 according to a further example. Here, the switching element 125 comprises a diode 201 and a series resistor 203 connected in series upstream of the diode 201. By means of the diode 201 and the series resistor 203 connected in series, the time of the switching process of the switching element 125 at which the parallel connection of the first circuit branch 119 and the second circuit branch 121 is transferred into the series connection of the first relay 103 and the second relay 105, can be coupled to the voltage difference between the first circuit branch 119 and the second circuit branch 121. The switching element 125 accordingly switches as soon as the voltage difference between the first circuit branch 119 and the second circuit branch 121 corresponds to the forward voltage of the diode 201.

[0071] In a further example (not shown in the figures), the switching element 125 comprises a plurality of diodes connected in series. In a further example, the switching element 125 additionally comprises a plurality of series resistors connected in series. As a result, the point in time of the switching process of the switching element 125 can be changed in comparison to the circuit with a single diode 201 and a single series resistor 203.

[0072] FIG. 3 shows an equivalent circuit diagram of a relay module 300 according to a further example. In this case, the switching element 125 comprises a transistor 301. In the example shown, the transistor 301 is a PNP bipolar transistor. In a further example, it is a different transistor, in particular an NPN bipolar transistor.

[0073] The transistor 301 is connected via the base connection to a voltage divider 303, which comprises a first resistor 305 and a second resistor 307. The transistor 301 is additionally electrically connected via the base connection to an RC element 309, which comprises a third resistor 311 and a third capacitor 313. Via the dimensioning of the RC element 309 and the first resistor 305 and the second resistor 307 of the voltage divider 303, the switching instant of the transistor 301 can be coordinated with the instant of the complete tightening of the first armature and the second armature, i.e., the switching instant of the switching element 125 can be coupled to reaching the holding state of the relay module 100, in particular it is coupled to that.

[0074] In the example shown in FIG. 3, the first circuit branch 119 additionally comprises a first blocking diode 315 and the second circuit branch 121 comprises a second blocking diode 317. The first blocking diode 315 and the second blocking diode 317 are arranged between the first relay 103 and the first capacitor 115 or the second capacitor 117 and the second relay 105, respectively, such that the first blocking diode 315 and the second blocking diode 317 are parts of the series connection with the first relay 104 and the second relay 105 when the transistor is in the conductive state and the switching element 103 is thus in the second switching state. In a further example, one or both blocking diodes 115, 117 can be omitted.

[0075] FIG. 4 shows an equivalent circuit diagram of a relay module 400 according to a further example. Here, the switching element 125 is the transistor 301, as described with respect to FIG. 3. The first circuit branch 119 also comprises the first blocking diode 315 and the second circuit branch 121 comprises the second blocking diode 317.

[0076] However, instead of the voltage divider 303 and the RC element 309 for controlling the switching time of the transistor 301, a controller 401, in particular a microcontroller, is provided which is connected to the base terminal of the transistor 301 and is configured to send a switching signal to the base terminal of the transistor 301 via an output of the controller. As a result, the switching element 125, i.e. the transistor 301, can be transferred from the first switching state to the second switching state.

[0077] To determine the point in time for switching over the switching element 125, the circuit according to the example shown in FIG. 4 comprises a current measuring device 403. The current measuring device 403 comprises a current measuring resistor (not shown). In a further example, the current is measured in a contactless manner by means of a clamp meter.

[0078] If the measured current reaches a limit value stored in the controller, the controller 401 generates a control signal and sends the control signal to the transistor 301 via an output of the controller 401 to switch the transistor 301 and thus to move the switching element 125 from the first switching state to the second switching state.

[0079] FIG. 5 shows an equivalent circuit diagram of a relay module 500 according to a further example. The relay module 500 according to the example of FIG. 5 corresponds to the relay module 300 of the example of FIG. 3. However, the transistor 301 is a field-effect transistor, in particular a metal-oxide-semiconductor field-effect transistor, abbreviated as MOSFET.

[0080] The voltage divider 303 and the RC element 309 are connected to the gate terminal of the MOSFET to adapt the switching time of the switching element 125 to the transition of the relay module 100 into the holding state.

[0081] FIG. 6 shows an equivalent circuit diagram of a relay module 600 in accordance with a further example. The relay module 600 according to the example of FIG. 6 corresponds to the relay module 400 of the example of FIG. 4. However, the transistor 301 is a field effect transistor, in particular a metal-oxide-semiconductor field effect transistor, abbreviated as MOSFET.

[0082] The controller 401 is connected to the gate terminal of the MOSFET to adapt the switching time of the switching element 125 to the transition of the relay module 100 into the holding state.

[0083] FIG. 7 shows an arrangement 700. The arrangement 700 comprises the relay module 100 and an emergency stop switch 701. In a further example, one of the relay modules 200, 300, 400, 500 or 600 is installed. In a further example, the arrangement 700 comprises the relay module 100 and a protective door switch or a magnetic switch or a light grid.

[0084] The relay module 100 is arranged such that the relay module 100 can fulfill a safety-relevant function of the arrangement 700. In the example shown, the relay module 100 is actuated by the emergency stop switch 701 to interrupt a circuit 703. The circuit 703 is partially shown in FIG. 7 for reasons of clarity. In particular, the circuit 703 can comprise further components in parts not shown or can be connected to machines. In this case, the first relay 103 and the second relay 105 interrupt the circuit 703 redundantly. This also ensures that the circuit 703 is interrupted if one of the two relays 103, 105 should have a malfunction, such as a jamming armature.

LIST OF REFERENCE NUMBERS

[0085] 100, 200, 300 relay module [0086] 400, 500, 600 relay module [0087] 103 first relay [0088] 105 second relay [0089] 107 first internal resistance [0090] 109 first inductor/coil [0091] 111 second internal resistance [0092] 113 second inductor/coil [0093] 115 first capacitor [0094] 117 second capacitor [0095] 119 first circuit branch [0096] 121 second circuit branch [0097] 123 voltage source [0098] 125 switching element [0099] 201 diode [0100] 203 series resistor [0101] 301 transistor [0102] 303 voltage divider [0103] 305 first resistance [0104] 307 second resistance [0105] 309 RC element [0106] 311 third resistance [0107] 313 third capacitor [0108] 315 first blocking diode [0109] 317 second blocking diode [0110] 401 control [0111] 403 current measuring device [0112] 700 arrangement [0113] 701 emergency stop switch [0114] 703 circuit