Safe digital quantity acquisition circuit and switch equipment

Abstract

The invention provides a safe digital quantity acquisition circuit and switch equipment. The circuit comprises a control circuit, an output circuit and an acquisition circuit, the control circuit generates a measurement signal according to an upstream input signal, and a signal output end of the control circuit is connected with the output circuit; the output circuit and the acquisition circuit are connected through a tested switching circuit, and the connection state of the tested switching circuit is judged by comparing an output signal of the output circuit, a recovery signal of the acquisition circuit and an upstream input signal of the control circuit. According to the invention, a non-fixed duty ratio square wave is adopted as a voltage output signal, so that the problem that a fixed signal is easily interfered by the outside is avoided; the optical coupler is used as a logic input and output element, electrical isolation is achieved through optical signal transmission, the influence of electromagnetic interference on a circuit is reduced, and meanwhile the interference hidden danger caused by mechanical contacts and moving parts is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of switching circuit, in particular, to a safe digital quantity acquisition circuit and switching device. BACKGROUND

[0002] With the development of electronic power technology, the application of power device is increasingly widespread. In the power automation device, the application of switching quantity acquisition is very common. The switching quantity acquisition circuit in the prior art acquires switching quantity through intermediate relay or acquires switching quantity through photoelectric coupler, which has the problems of poor anti-interference ability or easy failure.

[0003] In the Chinese patent document with publication number CN202586326U, a switching quantity acquisition circuit is disclosed, in which a switch K, a resistor R1, a resistor R2 and a light emitting diode of a photoelectric coupler are sequentially connected between a voltage input end and a voltage output end, a power input end is connected with a microprocessor MCU and a resistor R4 through a light sensitive diode of the photoelectric coupler U, the other end of the resistor R4 is grounded, the acquisition circuit further comprises an inductor L and a resistor R3, the inductor L is connected between the voltage input end and the switch K, one end of the resistor R3 is connected between the resistors R1 and R2, and the other end is connected with the negative electrode of the light emitting diode of the photoelectric coupler. In the switching quantity acquisition circuit disclosed in the scheme, when the external switching quantity K is connected, the current flows from the positive electrode V+ of the power supply through the resistor R1, then through the resistor R2 to the light emitting diode inside the photoelectric coupler to the negative electrode V- of the power supply, forming a loop, and lighting the light emitting diode inside the photoelectric coupler. The light sensitive diode inside the photoelectric coupler is turned on after being illuminated, and the signal is sent to the MCU; when disturbed by surge voltage and power frequency interference signal, the inductor L can inhibit the inflow of the interference signal, and the resistor R3 can discharge the negative half wave of the reverse surge voltage and power frequency interference signal. However, in the disclosed switching quantity acquisition circuit, detection errors are easily caused when disturbed by external interference or external switching quantity fluctuation. SUMMARY

[0004] In view of the defects in the prior art, the purpose of the present application is to provide a safe digital quantity acquisition circuit and switching device.

[0005] According to the safe digital quantity acquisition circuit provided by the present application, the control circuit, the output circuit and the acquisition circuit are connected in series.

[0006] The control circuit generates a measurement signal according to the upstream input signal, and the signal output end of the control circuit is connected with the output circuit.

[0007] The output circuit and the acquisition circuit are connected through the measured switching circuit, and the connection state of the measured switching circuit is judged by comparing the output signal of the output circuit, the acquisition signal of the acquisition circuit and the upstream input signal of the control circuit.

[0008] Preferably, the control circuit comprises: a voltage dividing resistor R154, a voltage dividing resistor R155, a transistor Q19, a transistor Q24, a capacitor C104, a capacitor C108, a capacitor C110, a capacitor C109, a second voltage dividing resistor R134, a second voltage dividing resistor R176, a diode D63, a diode D66 and an inductor T1;

[0009] One end of the voltage dividing resistor R154 is connected with the input D1, and the other end is connected with the base of the transistor Q19. The emitter of the transistor Q19 is grounded. The capacitor C104, the capacitor C108 and the second voltage dividing resistor R134 are connected in parallel, and one end of the parallel connection is connected with the collector of the transistor Q19 and the A1 end of the inductor T1, and the other end is connected with the positive electrode of the diode D63. The negative electrode of the diode D63 is connected with the 20DV and the center end A3 of the inductor T1.

[0010] One end of the voltage dividing resistor R155 is connected with the input The other end is connected with the base of the transistor Q24. The emitter of the transistor Q24 is grounded. The capacitor C110, the capacitor C109 and the second voltage dividing resistor R176 are connected in parallel, and one end of the parallel connection is connected with the collector of the transistor Q24 and the A4 end of the inductor T1, and the other end is connected with the positive electrode of the diode D66. The negative electrode of the diode D66 is connected with the 20DV and the center end A3 of the inductor T1.

[0011] Preferably, the output circuit comprises: an optocoupler N12, an optocoupler N14, a resistor R158, a resistor R153, a resistor R169, a resistor R163, a resistor R170 and a resistor R171;

[0012] The positive electrode of the emitter of the optocoupler N12 is connected with the negative electrode of the emitter of the optocoupler N14. The negative electrode of the emitter of the optocoupler N12 is connected with the positive electrode of the emitter of the optocoupler N14. The resistor R153 and the resistor R169 are connected in parallel, and one end of the parallel connection is connected with the negative electrode of the emitter of the optocoupler N12 and the positive electrode of the emitter of the optocoupler N14, and the other end is connected with the output CCO1. The resistor R170 and the resistor R171 are connected in parallel, and one end of the parallel connection is connected with the B4 end of the inductor T1, and the other end is connected with the output CCO2. The receiving end E of the optocoupler N12 is connected with OV, and the receiving end C of the optocoupler N12 is connected with one end of the resistor R158 and The other end of the resistor R158 is connected with 5VDC. The receiving end E of the optocoupler N14 is connected with OV, and the receiving end C of the optocoupler N14 is connected with one end of the resistor R163 and T1. The other end of the resistor R163 is connected with 5VDC.

[0013] Preferably, the acquisition circuit comprises: a capacitor C106, a resistor R180, a resistor R166, a resistor R161, a resistor R159, an optocoupler N16 and an optocoupler N26;

[0014] The one end of the resistor R180 is connected with the one end of the capacitor C106 and the input CCI1, and the other end is connected with the negative pole of the emitter of the photo-coupler N16 and the positive pole of the emitter of the photo-coupler N26, the resistor R166 is connected with the one end of the capacitor C106 and the input The other end is connected with the positive pole of the emitter of the photo-coupler N16 and the negative pole of the emitter of the photo-coupler N26, the receiving end E of the photo-coupler N16 is connected with 0V, the receiving end C of the photo-coupler N16 is connected with the resistor R161 and R1, the other end of the resistor R161 is connected with 5VDC, the receiving end E of the photo-coupler N26 is connected with 0V, the receiving end C of the photo-coupler N26 is connected with the resistor R159 and The other end of the resistor R159 is connected with 5VDC.

[0015] Preferably, the input of D1 and D2 in the control circuit uses a non-fixed duty ratio square wave, the duty ratio of which is controlled by the upstream CPU, the high voltage is 5VDC, and the input voltages of D1 and are opposite to each other.

[0016] Preferably, the connection state of the measured switch circuit includes a positive connection state, a reverse connection state, an open circuit state and a short circuit state; the connection state of the measured switch circuit corresponds to the connection relationship of the output circuit and the collection circuit as follows:

[0017] The positive connection state: CCO1 and CCI1 are connected, and CCO2 and CCI2 are connected;

[0018] The reverse connection state: CCO1 and are connected, and CCI1 are connected;

[0019] The open circuit state: CCO1 and are open circuits;

[0020] The short circuit state: CCO1 and are short circuits.

[0021] Preferably, when in the positive connection state: T1=D1, R1=D1,

[0022] Preferably, when in the reverse connection state: T1=D1,

[0023] Preferably, when in the open circuit state:

[0024] When in the short circuit state: T1=D1,

[0025] The application provides a switch device, which comprises the safe digital quantity acquisition circuit.

[0026] Compared with the prior art, the application has the following beneficial effects:

[0027] 1. The application realizes the acquisition function of the circuit switch state by adopting the comparison method of input and output waveforms, has strong anti-interference ability, and can monitor the fault of the external circuit.

[0028] 2. The application adopts the optical coupling as a logic input and output element, realizes the electrical isolation by using the optical signal transmission, reduces the influence of electromagnetic interference on the circuit, avoids the interference hidden danger caused by the mechanical contact and the moving part, and realizes the functions of long service life, impact resistance and strong electromagnetic interference resistance.

[0029] 3. The application can accurately identify four connection states of the external switch by comparing the consistency of the output waveform and the back-off waveform; when detecting abnormal states such as open circuit and short circuit, the system can automatically guide to the safe state, and effectively avoid the risk caused by the abnormal state. BRIEF DESCRIPTION OF DRAWINGS

[0030] Other features, objects and advantages of the application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0031] Figure 1 It is a schematic diagram of electronic elements of the control circuit and the output circuit in the application;

[0032] Figure 2 It is a schematic diagram of electronic elements of the acquisition circuit in the application;

[0033] Figure 3 It is a schematic diagram of the connection between CCO1 and CCI1 in the application, and a schematic diagram of the connection;

[0034] Figure 4 It is a current waveform comparison diagram of input and output in the application.

[0035] BRIEF DESCRIPTION OF DRAWINGS:

[0036] Control circuit 1; output circuit 2; acquisition circuit 3. DETAILED DESCRIPTION

[0037] The application will be described in detail below in combination with specific embodiments. The following embodiments will help those skilled in the art to further understand the application, but do not limit the application in any form. It should be pointed out that those skilled in the art can make several changes and improvements without departing from the concept of the application. These all belong to the protection scope of the application.

[0038] The application discloses a safe digital quantity acquisition circuit. The circuit uses four lines to acquire switch quantity, wherein CCO1 and are voltage outputs, CCI1 and are voltage back acquisition, the voltage output uses a non-fixed duty ratio square wave, the duty ratio of which is controlled by a CPU, the switch quantity state is returned by comparing the decoded back acquisition waveform with the output waveform, and if an abnormal state is found through comparison, the system is guided to a safe state.

[0039] Referring to Figure 1 and Figure 2 , the safe digital quantity acquisition circuit comprises a control circuit 1, an output circuit 2 and an acquisition circuit 3. The inductance end output of the control circuit 1 is connected with the output circuit 2. There are four connection relationships between the output circuit 2 and the acquisition circuit 3, which are realized by changing the input of external switch quantity. The four connection relationships are that CCO1 and CCI1 are connected, and are connected; CCO1 and are connected, and CCI1 are connected; CCO1 and are disconnected; CCO1 and are short-circuited.

[0040] The circuit structures of the constituent circuits are described in detail below.

[0041] The control circuit 1 comprises voltage dividing resistors R154 and R155, transistors Q19 and Q24, capacitors C104, C108 and C110, capacitor C109, second voltage dividing resistors R134 and R176, diodes D63 and D66 and an inductor T1. One end of the voltage dividing resistor R154 is connected with an input D1, and the other end is connected with the base of the transistor Q19. The emitter of the transistor Q19 is connected with the ground. The capacitors C104, C108 and the second voltage dividing resistor R134 are connected in parallel, and one end of the parallel connection is connected with the collector of the transistor Q19 and the A1 end of the inductor T1. The other end is connected with the positive electrode of the diode D63. The negative electrode of the diode D63 is connected with the 20DV and the center end A3 of the inductor T1. One end of the voltage dividing resistor R155 is connected with the input , and the other end is connected with the base of the transistor Q24. The emitter of the transistor Q24 is connected with the ground. The capacitors C110, C109 and the second voltage dividing resistor R176 are connected in parallel, and one end of the parallel connection is connected with the collector of the transistor Q24 and the A4 end of the inductor T1. The other end is connected with the positive electrode of the diode D66. The negative electrode of the diode D66 is connected with the 20DV and the center end A3 of the inductor T1.

[0042] The output circuit 2 includes: optocoupler N12, optocoupler N14, resistance R158, resistance R153, resistance R169, resistance R163, resistance R170, resistance R171, wherein: the positive pole of the emitter of the optocoupler N12 is connected with the negative pole of the emitter of the optocoupler N14, the negative pole of the emitter of the optocoupler N12 is connected with the positive pole of the emitter of the optocoupler N14, the resistance R153 and the resistance R169 are connected in parallel, one end of which is connected with the negative pole of the emitter of the optocoupler N12 and the positive pole of the emitter of the optocoupler N14, and the other end of which is connected with CCO1, the resistance R170 and the resistance R171 are connected in parallel, one end of which is connected with the B4 end of the inductor T1, and the other end of which is connected with the other end of the resistance R158 is connected with 5VDC, the E pole of the receiving end of the optocoupler N12 is connected with OV, and the C pole of the receiving end of the optocoupler N12 is connected with one end of the resistance R158 and the other end of the resistance R158 is connected with 5VDC, the E pole of the receiving end of the optocoupler N14 is connected with OV, and the C pole of the receiving end of the optocoupler N14 is connected with one end of the resistance R163 and T1, and the other end of the resistance R163 is connected with 5VDC.

[0043] The collection circuit 3 includes: capacitor C106, resistance R180, resistance R166, resistance R161, resistance R159, optocoupler N16, optocoupler N26, wherein: one end of the resistance R180 is connected with one end of the capacitor C106 and CCI1, and the other end of the resistance R180 is connected with the negative pole of the emitter of the optocoupler N16 and the positive pole of the emitter of the optocoupler N26, the resistance R166 is connected with one end of the capacitor C106 and the other end of the resistance R166 is connected with the positive pole of the emitter of the optocoupler N16 and the negative pole of the emitter of the optocoupler N26, the E pole of the receiving end of the optocoupler N16 is connected with OV, the C pole of the receiving end of the optocoupler N16 is connected with the resistance R161 and R1, the other end of the resistance R161 is connected with 5VDC, the E pole of the receiving end of the optocoupler N26 is connected with OV, and the C pole of the receiving end of the optocoupler N26 is connected with the resistance R159 and the other end of the resistance R159 is connected with 5VDC.

[0044] Figure 3 CCO1 and CCI1 are connected, and the connection of which is connected with the contact of the safety relay, and different states of the relay will result in different connection of the circuit, and there are current state detectors at the sending end T and the receiving end R.

[0045] Figure 4 It is a current waveform comparison chart for input and output, which has four connection states, state 1 (Normal Position), state 2 (Reversed Position), open circuit state (Open Circuit), and short circuit state (Short Circuit).

[0046] The working principle of the safe digital quantity collection circuit disclosed in the application is described in further detail below.

[0047] D1 and The input of the control circuit 1 is a non-fixed duty cycle square wave, the duty cycle of which is controlled by the CPU, and the high voltage is 5VDC. The input voltages of D1 and are opposite to each other. When the input of D1 is high, the C electrode and the E electrode of the triode Q19 are turned on, and the triode Q24 is turned off. At this time, the current direction is from the 20V terminal to the OV direction of the triode Q19 through the inductor T1, and the inductor T1 generates an induced electromotive force at the B1 and B4 terminals, the direction of which is positive at the B1 terminal and negative at the B4 terminal, and the size is 40VDC. Conversely, when the input of D1 is low, the inductor T1 generates an induced electromotive force at the B1 and B4 terminals, the direction of which is negative at the B1 terminal and positive at the B4 terminal, and the size is 40VDC. At this time, the inductor T1 generates a square wave signal of ±40VDC at the B1 and B4 terminals.

[0048] This circuit determines the connection state between CCO1, CCI 1, and T1, R1, by comparing the states of D1, CCO1 and CCI 1.

[0049] State 1: CCO1 and CCI 1 are connected, and When the B1 terminal of the inductor T1 is positive and the B4 terminal is negative, a current loop is generated, the current direction is from CCO1 to CCI1, and then from to At this time, the light-emitting diode in the optocoupler N12 works, the C terminal and the E terminal of the optocoupler are connected, and the output is low. Conversely, T1 is high at this time. At the same time, in the collection circuit 3, the current flows from the anode of the optocoupler N26 to the cathode, the light-emitting diode works, the C terminal and the E terminal of the optocoupler are connected, and the output is low. Conversely, R1 is high at this time. At this time, it can be seen that T1 and R1 are high, and are low. Similarly, when the B1 terminal of the inductor T1 is negative and the B4 terminal is positive, T1 and R1 can be obtained as low, and are high. This case is Figure 4 the NormalPosition in State 1, the waveforms of T and R are completely consistent, and are completely consistent with the input waveform of D1. Therefore, the states of T1 and R1 can be determined to be the same as D1 by software comparison, and State 2: CCO1 and CCI1 are connected, and CCI1 are connected, i.e. CCO1 and CCI1 are connected, and are connected.

[0050] State 2: CCO1 and CCI1 are connected, and CCI1 are connected, i.e. CCO1 and CCI1 are connected, and CCI1 are connected: since this case is the reverse of the collection circuit 3 bit direction of case 1, we can draw the same conclusion that this time T1 and State 2: CCO1 and CCI1 are connected, and R1 state and are the same, the software determines that CCO1 and CCI1 are connected, and CCI1 are connected, i.e. CCO1 and CCI1 are connected, and CCI1 are connected, as Figure 4 State 2 (ReversedPosition).

[0051] State 3: CCO1 and CCI1 are disconnected: at this time, the output circuit 2 and the collection circuit 3 have no current, and the optocouplers N12, N14, N16, N26 are all in the off state, and the corresponding T1, R1, are all high level, so the software determines that when T1, R1, State 3: CCO1 and CCI1 are disconnected, i.e. CCO1 and CCI1 are disconnected, Figure 4 State 3 (Open Circuit).

[0052] State 4: CCO1 and CCI1 are short-circuited: at this time, the optocouplers N16 and N26 of the collection circuit 3 do not work, and R1 and are all high level. The optocouplers N12 and N14 in the output circuit 2 work normally, and T1 and State 4: CCO1 and CCI1 are short-circuited, i.e. CCO1 and CCI1 are short-circuited, are opposite. Therefore, the software determines that T1 state and D1 are the same, State 4: CCO1 and CCI1 are short-circuited, i.e. CCO1 and CCI1 are short-circuited, are the same, and R1 and are all high level, i.e. CCO1 and CCI1 are short-circuited, as Figure 4 State 4 (Short Circuit).

[0053] As shown in the following table, the conditions for the software to determine the circuit state are as follows:

[0054] Normal: T1 = D1 R1 = D1

[0055] Reversed: T1 = D1

[0056] Open circuit: (high)

[0057] Short circuit: T1 = D1 (high)

[0058]

[0059] The application also provides a switching device, comprising a switching circuit, and a safety digital acquisition circuit for measuring the state of the switching circuit.

[0060] The specific embodiments of the application are described above. It needs to be understood that the application is not limited to the specific embodiments described above, and various changes or modifications can be made by those skilled in the art within the scope of the claims, which does not affect the essential content of the application. The embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily without conflict.

Claims

1. A safe digital quantity acquisition circuit, characterized in that: include: Control circuit (1), output circuit (2) and acquisition circuit (3); The control circuit (1) generates a measurement signal according to an upstream input signal, and a signal output end of the control circuit (1) is connected to the output circuit (2); The output circuit (2) and the acquisition circuit (3) are connected via the switch circuit under test, and the connection state of the switch circuit under test is determined by comparing the output signal of the output circuit (2), the return signal of the acquisition circuit (3), and the upstream input signal of the control circuit (1).

2. The safe digital quantity acquisition circuit according to claim 1, characterized in that: The control circuit (1) comprises: a voltage-dividing resistor R154, a voltage-dividing resistor R155, a transistor Q19, a transistor Q24, a capacitor C104, a capacitor C108, a capacitor C110, a capacitor C109, a second voltage-dividing resistor R134, a second voltage-dividing resistor R176, a diode D63, a diode D66 and an inductor T1; One end of a voltage-dividing resistor R154 is connected to input D1, and the other end is connected to the base of transistor Q19. The emitter of transistor Q19 is grounded. Capacitor C104, capacitor C108, and a second voltage-dividing resistor R134 are connected in parallel. One end is connected to the collector of transistor Q19 and terminal A1 of inductor T1, and the other end is connected to the anode of diode D63. The cathode of diode D63 is connected to 20DV and connected to the center terminal A3 of inductor T1. One end of the voltage dividing resistor R155 is connected to the input The other end is connected to the base of the transistor Q24. The emitter of the transistor Q24 is grounded. The capacitor C110, the capacitor C109, and the second voltage-dividing resistor R176 are connected in parallel. One end is connected to the collector of the transistor Q24 and the A4 end of the inductor T1, and the other end is connected to the anode of the diode D66. The cathode of the diode D66 is connected to 20DV and connected to the center end A3 of the inductor T1.

3. The safe digital quantity acquisition circuit according to claim 1, characterized in that: The output circuit (2) includes: an optical coupler N12, an optical coupler N14, a resistor R158, a resistor R153, a resistor R169, a resistor R163, a resistor R170 and a resistor R171; The positive electrode of the emitter of optocoupler N12 is connected to the negative electrode of the emitter of optocoupler N14, and the negative electrode of the emitter of optocoupler N12 is connected to the positive electrode of the emitter of optocoupler N14. The resistor R153 and the resistor R169 are connected in parallel, and one end is connected to the negative electrode of the emitter of optocoupler N12 and the positive electrode of the emitter of optocoupler N14, and the other end is connected to the output CCO1. The resistor R170 and the resistor R171 are connected in parallel, and one end is connected to the B4 end of the inductor T1, and the other end is connected to the output Connected, the receiving end E of the optocoupler N12 is connected to OV, and the receiving end C of the optocoupler N12 is connected to one end of the resistor R158 and The other end of the resistor R158 is connected to 5VDC, the receiving end E of the optocoupler N14 is connected to 0V, the receiving end C of the optocoupler N14 is connected to one end of the resistor R163 and T1, and the other end of the resistor R163 is connected to 5VDC.

4. The safe digital quantity acquisition circuit according to claim 1, characterized in that: The acquisition circuit (3) includes: a capacitor C106, a resistor R180, a resistor R166, a resistor R161, a resistor R159, an optical coupler N16, and an optical coupler N26; One end of resistor R180 is connected to one end of capacitor C106 and input CCI1, and the other end is connected to the negative electrode of the emitter of optocoupler N16 and the positive electrode of the emitter of optocoupler N26. The other end is connected to the positive electrode of the emitter of the optocoupler N16 and the negative electrode of the emitter of the optocoupler N26. The E pole of the receiving end of the optocoupler N16 is connected to 0V. The C pole of the receiving end of the optocoupler N16 is connected to the resistor R161 and R1. The other end of the resistor R161 is connected to 5VDC. The E pole of the receiving end of the optocoupler N26 is connected to 0V. The C pole of the receiving end of the optocoupler N26 is connected to the resistor R159 and The other end of resistor R159 is connected to 5VDC.

5. The safe digital quantity acquisition circuit according to claim 2, characterized in that: In the control circuit (1), D1 and The input of the terminal uses a non-fixed duty cycle square wave, whose duty cycle is controlled by the upstream CPU. The high voltage is 5VDC. D1 and The input voltages are opposite to each other.

6. The safe digital quantity acquisition circuit according to claim 1, characterized in that: The connection states of the switch circuit under test include a forward connection state, a reverse connection state, an open circuit state, and a short circuit state; the connection state of the open-end circuit under test corresponds to the connection relationship between the output circuit (2) and the acquisition circuit (3): The positive connection state: CCO1 and CCI1 are connected, and connected; The reverse connection state: CCO1 and connected, Connected to CCI1; The circuit breaker status: CCO1 and Circuit breaker; The circuit breaker status: CCO1 and Short circuit.

7. The safe digital quantity acquisition circuit according to claim 6, characterized in that: When in positive connection state: T1=D1, R1=D1, 8. The safe digital quantity acquisition circuit according to claim 6, characterized in that: When in reverse connection: T1=D1, 9. The safe digital quantity acquisition circuit according to claim 6, characterized in that: When in the off state: When in short circuit state: T1=D1, 10. A switchgear, characterized in that: The invention comprises the safe digital quantity acquisition circuit according to any one of claims 1 to 9.

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