A safety interlocking multi-relay AC input circuit
By employing a dual-relay isolation design and redundant control, the safety and compatibility issues of single-relay control power paths are resolved, resulting in improved safety and stability. This avoids equipment malfunctions and electric shock risks caused by contact adhesion and coil failure.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ADTECH SHENZHEN TECH
- Filing Date
- 2025-07-28
- Publication Date
- 2026-07-31
AI Technical Summary
Traditional single-relay control power paths have risks such as contact sticking and coil failure, which can lead to equipment malfunction or electric shock hazards. In addition, low-voltage processor chips cannot directly drive high-voltage relays, resulting in signal compatibility issues.
The system employs a dual-relay isolation design, ensuring no residual voltage during maintenance through safety and control circuits. Redundant control is achieved using dual-circuit safety relays, with power supply only activated when both relays are simultaneously engaged, preventing power outages caused by single-point faults and coordinating the timing of actions between the safety relays and the processor control.
It significantly improves system safety, eliminates the risk of electric shock from direct access to the control system with 220V AC power, and coordinates the level matching problem between the low-voltage processor chip and the high-voltage relay, ensuring stable system operation.
Smart Images
Figure CN224582843U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of electronic circuit technology, and in particular to a safety interlocking multi-relay AC input circuit. Background Technology
[0002] In industrial robots and automation equipment, reliable switching and safe isolation of AC power are core requirements for ensuring stable system operation. Traditional solutions use a single relay to directly control the power path, but this carries risks such as contact sticking and coil failure, potentially leading to equipment malfunction or electric shock. With increasing demands for control loop reliability from international safety standards (such as IEC 60204-1 and ISO 13849), dual-loop safety relay architectures are becoming mainstream. However, this architecture has drawbacks related to signal compatibility, such as the level matching issue where low-voltage processor chips cannot directly drive high-voltage relays. Utility Model Content
[0003] The purpose of this invention is to achieve physical breakpoint isolation through dual relays, ensuring no residual voltage during maintenance, and to provide redundancy through dual-circuit safety relays for single-point faults such as relay contact sticking and coil failure. This invention proposes a safety interlocking multi-relay AC input circuit.
[0004] To achieve the above objectives, the present invention adopts the following technical solution:
[0005] A safety interlocking multi-relay AC input circuit includes:
[0006] The system includes a safety circuit, a control circuit, and a switching circuit; the switching circuit is equipped with AC relays K1, K2, and K3.
[0007] The safety circuit is connected to the conversion circuit, and the control circuit is connected to AC relays K1, K2, and K3 in the conversion circuit. The control circuit is used to control the on / off state of AC relays K1, K2, and K3, thereby controlling the on / off state of AC power and the short circuit of the charging resistor.
[0008] The safety circuit includes a teach pendant, a safety relay, an emergency stop terminal, a rotary switch, and an optocoupler. The emergency stop terminal is connected end-to-end to the switch section of the teach pendant and is connected in series with the control pin of the safety relay to form a dual-loop control.
[0009] Preferably, the safety circuit further includes a motherboard, which is connected to a safety relay, an emergency stop terminal, and a rotary switch.
[0010] Preferably, the safety circuit further includes L OUT Interface, N OUT Interface, via LOUT Interface, N OUT Interface connection conversion circuit.
[0011] Preferably, the safety circuit further includes AC contactors KM1 and KM2, the engagement of which is controlled by a safety relay.
[0012] Preferably, the safety relay is powered by an independent switching power supply module with a 24V operating power. When its S11 and S12 pins are short-circuited and its S21 and S22 pins are short-circuited, the contacts close, connecting the normally open pin of the rotary switch in parallel to the two ends of the teach pendant pin, thus serving as a bypass teach pendant switch.
[0013] Preferably, the conversion circuit includes varistor VR1, varistor VR2, and varistor VR3; varistor VR1 and varistor VR3 are connected in series, and varistor VR2 is connected in parallel with the series branch of varistor VR1 and varistor VR3. OUT Interface, N OUT The interfaces are connected to the two ends of the series branch of varistor VR1 and varistor VR3, respectively.
[0014] Preferably, the conversion circuit includes a protection circuit consisting of a varistor VR1, a varistor VR2, a varistor VR3, a gas discharge tube GS1, a fuse F1, and safety capacitors C9 and C10.
[0015] Preferably, the conversion circuit includes a rectifier bridge U1, electrolytic capacitors C3, C4, C5, C6, C7, C8, C42, and C43. The rectifier bridge U1 converts AC power into DC power, and the eight electrolytic capacitors C3, C4, C5, C6, C7, C8, C42, and C43 filter the AC power to obtain a stable 310V DC power.
[0016] Preferably, the control circuit includes four phototransistors; the control circuit is divided into high-voltage and low-voltage sides at both ends of the phototransistors; the high-voltage side is powered by a 24V network and returns to the 0V network through an AC relay coil, and its on / off state is controlled by the Relay_CTR1 and Relay_CTR2 signals on the low-voltage side, and the on / off state of the four phototransistors is controlled simultaneously by the Relay_CTR1 and Relay_CTR2 signals.
[0017] Preferably, the control circuit includes a control terminal, which is connected to an emergency stop terminal.
[0018] Preferably, the motherboard is provided with a fan, a buzzer, and a button battery mounting position.
[0019] Compared with existing technologies,
[0020] In this embodiment of the invention, physical breakpoints are achieved through dual relay isolation, ensuring no residual voltage during maintenance. For single-point faults such as relay contact sticking and coil failure, redundancy is achieved through dual-circuit safety relays. The AC contactor controlled by the safety relay is turned on first, and the AC relay controlled by the processor is energized later. Reverse operation is performed during power failure to avoid arc damage. Real-time control is achieved through a teach pendant, rotary switch, and external terminals. Through redundant contact design, power can only be turned on when both relays are energized simultaneously. Single-point faults automatically trigger power failure, significantly improving system safety, solving the risk of electric shock from direct access to the control system with 220V AC power, resolving the level matching problem that the low-voltage processor chip cannot directly drive the high-voltage relay, and coordinating the timing of the operation of the safety relay and the processor-controlled relay. Attached Figure Description
[0021] The above and other objects, features, and advantages of exemplary embodiments of the present disclosure will become readily apparent upon reading the following detailed description with reference to the accompanying drawings. In the drawings, several embodiments of the present disclosure are illustrated by way of example and not limitation, and like or corresponding reference numerals denote like or corresponding parts, wherein:
[0022] Figure 1 This is a schematic diagram of a safety interlocking multi-relay AC input circuit proposed in this utility model;
[0023] Figure 2 This is a schematic diagram of a safety circuit proposed in this utility model;
[0024] Figure 3 This is a schematic diagram of a conversion circuit proposed in this utility model;
[0025] Figure 4 This is a schematic diagram of a control loop proposed in this utility model. Detailed Implementation
[0026] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.
[0027] The specific embodiments of this disclosure will now be described in detail with reference to the accompanying drawings.
[0028] Reference Figure 1 The diagram shows a schematic of a safety interlocking multi-relay AC input circuit according to an embodiment of the present invention, including:
[0029] The system includes a safety circuit, a control circuit, and a switching circuit; the switching circuit is equipped with AC relays K1, K2, and K3.
[0030] In this embodiment of the utility model, the safety circuit is connected to the conversion circuit, and the control circuit is connected to the AC relays K1, K2, and K3 in the conversion circuit. The control circuit is used to control the on / off state of the AC relays K1, K2, and K3, thereby controlling the on / off state of the AC power and the short circuit of the charging resistor.
[0031] In a further embodiment of this utility model, the safety circuit includes a teach pendant, a safety relay, an emergency stop terminal, a rotary switch, and an optocoupler. The emergency stop terminal is connected end-to-end with the switch portion of the teach pendant and is connected in series with the control pin of the safety relay to form a dual-loop control.
[0032] In this embodiment of the invention, physical breakpoints are achieved through dual relay isolation, ensuring no residual voltage during maintenance. For single-point faults such as relay contact sticking and coil failure, redundancy is achieved through dual-circuit safety relays. The AC contactor controlled by the safety relay is turned on first, and the AC relay controlled by the processor is energized later. Reverse operation is performed during power failure to avoid arc damage. Real-time control is achieved through a teach pendant, rotary switch, and external terminals. Through redundant contact design, power can only be turned on when both relays are energized simultaneously. Single-point faults automatically trigger power failure, significantly improving system safety, solving the risk of electric shock from direct access to the control system with 220V AC power, resolving the level matching problem that the low-voltage processor chip cannot directly drive the high-voltage relay, and coordinating the timing of the operation of the safety relay and the processor-controlled relay.
[0033] Reference Figure 2 The diagram shows a schematic of a safety circuit according to an embodiment of the present invention. The safety circuit also includes a motherboard, which is connected to a safety relay, an emergency stop terminal, and a rotary switch.
[0034] In practical applications of this utility model embodiment, the safety circuit further includes L OUT Interface, N OUT Interface, via L OUT Interface, N OUT Interface connection conversion circuit.
[0035] Furthermore, the safety circuit also includes AC contactors KM1 and KM2, the engagement of which is controlled by a safety relay.
[0036] In this embodiment of the utility model, the safety relay is powered by an independent switching power supply module with a 24V operating power. When its S11 and S12 pins are short-circuited and its S21 and S22 pins are short-circuited, the contacts are engaged, connecting the normally open pin of the rotary switch in parallel to the two ends of the teach pendant pin, thus serving as a bypass teach pendant switch.
[0037] Figure 2 This is a schematic diagram of the safety circuit: 220V AC power is introduced from AC contactor KM1 and output from AC contactor KM2 connected in series with it. The engagement of both AC contactors is controlled by a safety relay. The safety relay is supplied with 24V operating power by an independent switching power supply module. Its contacts engage when pins S11 and S12 are short-circuited and pins S21 and S22 are short-circuited. Here, the emergency stop terminal is connected end-to-end to the teaching pendant's switching section, and connected in series with the safety relay's control pins as shown in the diagram, forming a dual-loop control design. To ensure normal power supply when the teaching pendant is not in use, the normally open pin of the rotary switch is connected in parallel across the teaching pendant pins, acting as a bypass for the teaching pendant switch. Simultaneously, the remaining normally closed pin is used for feedback.
[0038] When Y1 and Y2 are short-circuited, the segment relay is reset; when S11 and S12 are short-circuited and S21 and S22 are short-circuited, the contacts of the safety relay are engaged, and 220V AC power can flow out from KM2 and be connected to the motherboard PCB through the power line.
[0039] Reference Figure 3 The diagram shows a schematic of a conversion circuit according to an embodiment of the present invention. The conversion circuit includes a varistor VR1, a varistor VR2, and a varistor VR3. Varistors VR1 and VR3 are connected in series, and varistor VR2 is connected in parallel with the series branch of varistor VR1 and VR3. The L... OUT Interface, N OUT The interfaces are connected to the two ends of the series branch of varistor VR1 and varistor VR3, respectively.
[0040] Specifically, the conversion circuit includes a protection circuit consisting of varistor VR1, varistor VR2, varistor VR3, gas discharge tube GS1, fuse F1, and safety capacitors C9 and C10.
[0041] In a preferred embodiment of this utility model, the conversion circuit includes a rectifier bridge U1, electrolytic capacitors C3, C4, C5, C6, C7, C8, C42, and C43. The rectifier bridge U1 converts AC power into DC power, and the eight electrolytic capacitors C3, C4, C5, C6, C7, C8, C42, and C43 filter the AC power to obtain a stable 310V DC power.
[0042] Figure 1 AC 220V output network L OUT N OUT Enter Figure 2 After passing through the middle section, the circuit first performs high-voltage and overcurrent protection operations through a protection circuit consisting of varistors VR1, VR2, VR3, gas discharge tube GS1, fuse F1, and safety capacitors C9 and C10.
[0043] The current then flows into AC relays K1, K2, and K3. By controlling the on / off state of K1 and K2, the power output can be controlled; by controlling the on / off state of K3, the charging resistors (R3, R4, R5) can be controlled to prevent short circuits.
[0044] Then, the AC power is converted into DC power through the rectifier bridge U1, and filtered by eight electrolytic capacitors C3, C4, C5, C6, C7, C8, C42, and C43 to obtain a stable DC 310V DC power.
[0045] The eight electrolytic capacitors C3, C4, C5, C6, C7, C8, C42, and C43 have very high voltage and capacitance values. When they are directly connected to a power supply, the charging current required by the power supply is very large, which places too high demands on the external power supply. Therefore, K3 and R3, R4, and R5 are added to the circuit: After power-on, K3 must be in the open state. The current passes through the parallel R3, R4, and R5 and then charges the capacitors with a small current. After the capacitors are fully charged, K3 is closed, short-circuiting R3, R4, and R5. The current then flows directly through the contacts of K3 into the rectifier bridge.
[0046] Reference Figure 4The diagram shows a schematic of a control circuit according to an embodiment of the present invention. The control circuit includes four phototransistors. The control circuit is divided into high-voltage and low-voltage sides at both ends of the phototransistors. The high-voltage side is powered by a 24V network and returns to the 0V network through an AC relay coil. Its on / off state is controlled by the Relay_CTR1 and Relay_CTR2 signals on the low-voltage side. The on / off state of the four phototransistors is controlled simultaneously by the Relay_CTR1 and Relay_CTR2 signals.
[0047] On the other hand, such as Figure 4 As shown, the control circuit includes control terminals connected to the emergency stop terminal. The circuit is divided into high-voltage and low-voltage sides at the two ends of the phototransistor. The high-voltage side is powered by a 24V network, returning to the 0V network via an AC relay coil. Its on / off state is controlled by the low-voltage side signals Relay_CTR1 and Relay_CTR2. These two signals are provided by the main control chip on the PCB, simultaneously controlling the on / off state of four phototransistors, forming a dual-loop control design. The 220V AC power supply derived from the main board powers the coil of relay K3, and its on / off state is controlled by the Relay_CTR3 signal from the main control chip, allowing the electrolytic capacitor to be slowly charged through the charging resistor.
[0048] In the foregoing description of this specification, unless otherwise expressly specified and limited, the terms "fixed," "installed," "connected," or "joined" should be interpreted broadly. For example, the term "joined" can refer to a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; or it can refer to the internal communication of two components or the interaction between two components. Therefore, unless otherwise expressly limited in this specification, those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.
[0049] Based on the above description in this specification, those skilled in the art will also understand that terms used, such as "upper," "lower," "front," "rear," "left," "right," "length," "width," "thickness," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," "circumferential," "center," "longitudinal," "transverse," "clockwise," or "counterclockwise," are terms indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings of this specification. They are only for the purpose of facilitating the explanation of the present invention and simplifying the description, and do not imply that the device or element involved must have the specific orientation, or be constructed and operated in a specific orientation. Therefore, the above-mentioned orientation or positional relationship terms should not be understood or interpreted as limitations on the present invention.
[0050] Furthermore, the terms "first" or "second," etc., used in this specification to refer to numbers or ordinal numbers are for descriptive purposes only and should not be construed as indicating, explicitly or implicitly, relative importance or specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this specification, "a plurality of" means at least two, such as two, three, or more, unless otherwise explicitly specified.
[0051] While this specification has shown and described various embodiments of the present invention, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Many modifications, alterations, and alternatives will occur to those skilled in the art without departing from the spirit and essence of the present invention. It should be understood that various alternatives to the embodiments of the present invention described herein may be employed in the practice of the present invention. The appended claims are intended to define the scope of protection of the present invention and therefore cover the modular compositions, equivalents, or alternatives within the scope of these claims.
Claims
1. A safety interlocking multi-relay AC input circuit, characterized in that, include: Safety circuits, control circuits, and switching circuits; The conversion circuit is equipped with AC relays K1, K2, and K3; The safety circuit is connected to the conversion circuit, and the control circuit is connected to AC relays K1, K2, and K3 in the conversion circuit. The control circuit is used to control the on / off state of AC relays K1, K2, and K3, thereby controlling the on / off state of AC power and the short circuit of the charging resistor. The safety circuit includes a teach pendant, a safety relay, an emergency stop terminal, a rotary switch, and an optocoupler. The emergency stop terminal is connected end-to-end to the switch section of the teach pendant and is connected in series with the control pin of the safety relay to form a dual-loop control.
2. The safety interlocking multi-relay AC input circuit according to claim 1, characterized in that, The safety circuit also includes a main board, which is connected to a safety relay, an emergency stop terminal, and a rotary switch.
3. The safety interlocking multi-relay AC input circuit according to claim 2, characterized in that, The safety circuit also includes L OUT Interface, N OUT Interface, via L OUT Interface, N OUT Interface connection conversion circuit.
4. The safety interlocking multi-relay AC input circuit according to claim 3, characterized in that, The safety circuit also includes AC contactors KM1 and KM2, the engagement of which is controlled by a safety relay.
5. The safety interlocking multi-relay AC input circuit according to claim 2, characterized in that, The safety relay is powered by an independent switching power supply module with a 24V operating power. When pins S11 and S12 are short-circuited and pins S21 and S22 are short-circuited, the contacts close, connecting the normally open pin of the rotary switch in parallel to the two ends of the teach pendant pin, thus serving as a bypass teach pendant switch.
6. The safety interlocking multi-relay AC input circuit according to claim 3, characterized in that, The conversion circuit includes varistor VR1, varistor VR2, and varistor VR3; varistor VR1 and varistor VR3 are connected in series, and varistor VR2 is connected in parallel with the series branch of varistor VR1 and varistor VR3. OUT Interface, N OUT The interfaces are connected to the two ends of the series branch of varistor VR1 and varistor VR3, respectively.
7. The safety interlocking multi-relay AC input circuit according to claim 6, characterized in that, The conversion circuit includes a protection circuit consisting of varistor VR1, varistor VR2, varistor VR3, gas discharge tube GS1, fuse F1, and safety capacitors C9 and C10.
8. The safety interlocking multi-relay AC input circuit according to claim 7, characterized in that, The conversion circuit includes a rectifier bridge U1, electrolytic capacitors C3, C4, C5, C6, C7, C8, C42, and C43. The rectifier bridge U1 converts AC power into DC power, and the eight electrolytic capacitors C3, C4, C5, C6, C7, C8, C42, and C43 filter the AC power to obtain a stable 310V DC power.
9. The safety interlocking multi-relay AC input circuit according to claim 1, characterized in that, The control circuit includes four phototransistors; the control circuit is divided into high-voltage and low-voltage sides at both ends of the phototransistors; the high-voltage side is powered by a 24V network and returns to the 0V network through an AC relay coil, and its on / off state is controlled by the Relay_CTR1 and Relay_CTR2 signals on the low-voltage side, which simultaneously control the on / off state of the four phototransistors.
10. The safety interlocking multi-relay AC input circuit according to claim 9, characterized in that, The control circuit includes a control terminal, which is connected to an emergency stop terminal.