A safety relay with current monitoring

Abstract

The present invention belongs to the technical field of safety relays, and specifically is a safety relay with current monitoring, including: a power supply protection circuit, an MCU, an optocoupler 1, an optocoupler 2, a K1 common terminal, a K2 common terminal, a K3 common terminal, a K4 common terminal, a K1 normally open terminal, a K2 normally open terminal, a K3 normally open terminal, a K4 normally open terminal, and a load power supply. The digital current detection technology of the load circuit is seamlessly embedded in the quadruple safety relay to monitor the real-time current value of the load circuit, and transmit it to the upper monitoring system through communication to monitor the circuit current. At the same time, according to the actual circuit current monitoring status, a corresponding fault alarm output is performed. By observing the change of the current value, through the real-time monitoring and comparison of the load circuit current, the health status of the circuit load is predicted, and maintenance or replacement is performed in advance to avoid safety circuit failure and device shutdown.

Description

Technical Field

[0001] The invention relates to the technical field of safety relays, in particular to a safety relay with current monitoring. Background Art

[0002] Safety relays are composed of several relays and circuits in order to complement each other's abnormal defects and achieve complete relay functions with correct and low false operation. The lower the error and failure value, the higher the safety factor. Therefore, a variety of safety relays need to be designed to protect different levels of machinery. The main goal is to protect machine operators exposed to different levels of danger.

[0003] Conventional safety relays use a combination of contacts in series to achieve effective execution of safety actions. However, there is currently no effective monitoring method for the load circuit status, and no early warning of circuit safety actions can be given, requiring frequent personnel inspections. Summary of the invention

[0004] The purpose of the present invention is to provide a safety relay with current monitoring to solve the problem in the above background technology that there is no effective monitoring means, no early warning of the occurrence of loop safety action, and frequent personnel inspection is required.

[0005] To achieve the above object, the present invention provides the following technical solution: a safety relay with current monitoring, comprising:

[0006] Power supply protection circuit, MCU, optocoupler 1, optocoupler 2, K1 common end, K2 common end, K3 common end, K4 common end, K1 normally open end, K2 normally open end, K3 normally open end, K4 normally open end, load power supply;

[0007] Wherein, the power supply protection circuit is connected to the K1 relay power supply protection circuit, the K2 relay power supply protection circuit, the K3 relay power supply protection circuit, and the K4 relay power supply protection circuit, and the K1 relay power supply protection circuit, the K2 relay power supply protection circuit, the K3 relay power supply protection circuit, and the K4 relay power supply protection circuit are connected to the K1 relay coil, the K2 relay coil, the K3 relay coil, and the K4 relay coil respectively;

[0008] The K1 relay coil, K2 relay coil, K3 relay coil, and K4 relay coil correspond to the K1 common terminal, K2 common terminal, K3 common terminal, and K4 common terminal, the K1 common terminal is connected to the K2 common terminal, the K1 normally open terminal and K2 normally open terminal are connected to the K3 common terminal and K4 common terminal, and the K3 normally open terminal and K4 normally open terminal are connected to the sampling resistor;

[0009] The load power supply is connected to the fuse and the load, the fuse is connected to the common end of K1 and the optical coupler 2, and the sampling resistor is connected to the current detection amplifier and the load;

[0010] The optocoupler 1, optocoupler 2, and current detection amplifier are connected to the input end of the MCU, the MCU is connected to the power supply and signal isolation chip, the power supply and signal isolation chip is externally connected to a 24V power supply, the power supply and signal isolation chip is externally connected to a communication and fault output interface, the MCU output is connected to the photoelectric relay fault node output end, and the photoelectric relay fault node output end is connected to the communication and fault output interface.

[0011] Preferably, the power supply protection circuit and the optical coupler 1 are both powered by DCS.

[0012] Preferably, the output end of the MCU is connected to an LED fault light.

[0013] Preferably, the output end of the MCU is also connected to an EEPROM memory.

[0014] Preferably, the power supply and signal isolation chip outputs a 3.3V voltage to the MCU based on LDO.

[0015] Preferably, the 24V power supply outputs a 5V voltage to the power supply and signal isolation chip based on a DCDC power conversion circuit.

[0016] Preferably, the power supply and signal isolation chip is connected to the communication and fault output interface based on a 485 communication bus.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The digital current detection technology of the load circuit is seamlessly embedded in the quadruple safety relay to monitor the real-time current value of the load circuit, and transmit it to the upper monitoring system through communication for circuit current monitoring. At the same time, the corresponding fault alarm output is performed according to the actual circuit current monitoring status. By observing the changes in the current value, through real-time monitoring and comparison of the load circuit current, the health status of the circuit load is predicted, and maintenance or replacement is carried out in advance to avoid safety circuit failure and device shutdown. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a system logic block diagram of the present invention;

[0020] Figure 2 is a circuit schematic diagram of the present invention;

[0021] Figure 3 A circuit diagram of a sampling relay power supply in a monitoring circuit of the present invention;

[0022] Figure 4A circuit diagram for sampling a load power supply voltage in a monitoring loop of the present invention;

[0023] Figure 5 A circuit diagram of a monitoring circuit sampling a current in a load circuit of the present invention;

[0024] Figure 6 This is the monitoring circuit diagram of the present invention. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0027] Embodiment 1:

[0028] See also Figure 1-6 The present invention provides a technical solution: a safety relay with current monitoring, comprising: a power supply protection circuit, an MCU, an optocoupler 1, an optocoupler 2, a K1 common terminal, a K2 common terminal, a K3 common terminal, a K4 common terminal, a K1 normally open terminal, a K2 normally open terminal, a K3 normally open terminal, a K4 normally open terminal, and a load power supply; the power supply protection circuit and the optocoupler 1 are both based on DCS power supply;

[0029] Wherein, the power supply protection circuit is connected to the K1 relay power supply protection circuit, the K2 relay power supply protection circuit, the K3 relay power supply protection circuit, and the K4 relay power supply protection circuit, and the K1 relay power supply protection circuit, the K2 relay power supply protection circuit, the K3 relay power supply protection circuit, and the K4 relay power supply protection circuit are connected to the K1 relay coil, the K2 relay coil, the K3 relay coil, and the K4 relay coil respectively; the K1 relay coil, the K2 relay coil, the K3 relay coil, and the K4 relay coil correspond to the K1 common terminal, the K2 common terminal, the K3 common terminal, and the K4 common terminal, the K1 common terminal is connected to the K2 common terminal, and the K1 normally open terminal, the K2 normally open terminal, and the K3 normally open terminal correspond to the K4 common terminal. 2 normally open ends are connected to the common ends of K3 and K4, and the normally open ends of K3 and K4 are connected to the sampling resistor; the load power supply is connected to the fuse and the load, the fuse is connected to the common end of K1 and the optocoupler 2, and the sampling resistor is connected to the current detection amplifier and the load; the optocoupler 1, the optocoupler 2, and the current detection amplifier are connected to the input end of the MCU, the MCU is connected to the power supply and signal isolation chip, the power supply and signal isolation chip is externally connected to a 24V power supply, the power supply and signal isolation chip is externally connected to a communication and fault output interface, the MCU output is connected to the output end of the photoelectric relay fault node, and the output end of the photoelectric relay fault node is connected to the communication and fault output interface. The output end of the MCU is connected to an LED fault lamp, and the output end of the MCU is also connected to an EEPROM memory. The power supply and signal isolation chip outputs a 3.3V voltage to the MCU based on LDO. The 24V power supply outputs a 5V voltage to the power supply and signal isolation chip based on a DCDC power conversion circuit. The power supply and signal isolation chip is connected to the communication and fault output interface based on a 485 communication bus.

[0030] Analysis of the above content: This product has the conventional functions of a safety relay control module (isolation function between input and output signals, providing one normally open (NO) contact, relays adopting redundant technology of two-in-parallel connection followed by series connection and contact welding protection technology, output contact capacity of 5A, unique FDW design, compatible with dry and wet node connections without the need for additional external terminals.), and also adds a sampling resistor in the output channel, collects the current in the load loop, sends the collected information to the MCU module, and detects the working status of the load loop through signal processing.

[0031] like Figure 3 As shown in the figure, in this circuit, the power supply S IV+ (S IV-) signal is converted into the power signal by the optocoupler and then enters the MCU for signal processing. This part of the circuit is isolated from the safety relay by the optocoupler. When the 3VCC power supply circuit fails, the output of the safety relay circuit is not affected.

[0032] The S IV+ (S IV-) circuit failure does not affect the 3VCC circuit. Therefore, the monitoring circuit is safety-independent.

[0033] like Figure 4 As shown in the figure, in this circuit, the load power supply 24V+ (24V-) signal is converted by the optocoupler and then enters the MCU for signal processing. This part of the circuit is isolated from the safety relay by the optocoupler.

[0034] When the 3VCC power supply circuit fails, the output of the safety relay circuit is not affected.

[0035] like Figure 5 As shown, the current detection amplifier SGM8193A0 collects the tiny voltage difference between the two ends of the sampling resistor. It outputs the corresponding voltage value, enters the MCU for AD conversion, and is processed by the program into the corresponding current value. According to the circuit requirements, the power ground of SGM8193A0 and MCU is connected to 24V-.

[0036] Security Analysis

[0037] If the 4.5 pin of SGM8193A0 is short-circuited, the sampling resistor is short-circuited, and the safety relay outputs normally. It is not affected. At this time, AD1 outputs 0, which does not affect the MCU circuit.

[0038] If the 4.5 pin of SGM8193A0 is disconnected, the sampling resistor is not affected, and the safety relay outputs normally. At this time, AD1 outputs 0, which does not affect the MCU circuit.

[0039] like Figure 6 As shown, the monitoring circuit is powered by a separate power supply, and the input uses TVS and self-recovery fuses for overvoltage and overcurrent protection and electromagnetic compatibility. SGM61430 is used to output 5V to power the 485 chip. After the isolation chip IS3643LW, the output is isolated 5V, and then through the LDO to output 3.3V. Power the MCU, storage chip, optocoupler, photoelectric relay, and indicator light.

[0040] Overall function, when MCU works normally, it collects the current value of the load circuit, sets the normal current, outputs the abnormal current through the switch quantity and indicator light, and transmits the current value and alarm status to the control system through MODBUS communication. Circuit failure does not affect the safety status of the safety relay.

[0041] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention; therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is limited by the attached claims rather than the above description. Therefore, it is intended to include all changes within the meaning and scope of the equivalent elements of the claims in the present invention, and any figure marks in the claims should not be regarded as limiting the claims involved.

[0042] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A safety relay with current monitoring, characterized in that: include: Power supply protection circuit, MCU, optocoupler 1, optocoupler 2, K1 common end, K2 common end, K3 common end, K4 common end, K1 normally open end, K2 normally open end, K3 normally open end, K4 normally open end, load power supply; Wherein, the power supply protection circuit is connected to the K1 relay power supply protection circuit, the K2 relay power supply protection circuit, the K3 relay power supply protection circuit, and the K4 relay power supply protection circuit, and the K1 relay power supply protection circuit, the K2 relay power supply protection circuit, the K3 relay power supply protection circuit, and the K4 relay power supply protection circuit are connected to the K1 relay coil, the K2 relay coil, the K3 relay coil, and the K4 relay coil respectively; The K1 relay coil, K2 relay coil, K3 relay coil, and K4 relay coil correspond to the K1 common terminal, K2 common terminal, K3 common terminal, and K4 common terminal, the K1 common terminal is connected to the K2 common terminal, the K1 normally open terminal and K2 normally open terminal are connected to the K3 common terminal and K4 common terminal, and the K3 normally open terminal and K4 normally open terminal are connected to the sampling resistor; The load power supply is connected to the fuse and the load, the fuse is connected to the common end of K1 and the optical coupler 2, and the sampling resistor is connected to the current detection amplifier and the load; The optocoupler 1, optocoupler 2, and current detection amplifier are connected to the input end of the MCU, the MCU is connected to the power supply and signal isolation chip, the power supply and signal isolation chip is externally connected to a 24V power supply, the power supply and signal isolation chip is externally connected to a communication and fault output interface, the MCU output is connected to the photoelectric relay fault node output end, and the photoelectric relay fault node output end is connected to the communication and fault output interface.

2. A safety relay with current monitoring according to claim 1, characterized in that: The power supply protection circuit and optocoupler 1 are both based on DCS power supply.

3. A safety relay with current monitoring according to claim 1, characterized in that: The output end of the MCU is connected to an LED fault light.

4. A safety relay with current monitoring according to claim 1, characterized in that: The output end of the MCU is also connected to an EEPROM memory.

5. A safety relay with current monitoring according to claim 1, characterized in that: The power supply and signal isolation chip outputs a 3.3V voltage to the MCU based on LDO.

6. A safety relay with current monitoring according to claim 1, characterized in that: The 24V power supply outputs a 5V voltage to the power supply and signal isolation chip based on a DCDC power conversion circuit.

7. A safety relay with current monitoring according to claim 1, characterized in that: The power supply and signal isolation chip is connected with the communication and fault output interface based on the 485 communication bus.

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