Novel switching value signal collector for disconnection detection

Abstract

The invention relates to a novel switching value signal collector for disconnection detection. The novel switching value signal collector comprises a transformer T1, a full rectifier bridge composed of four diodes, a hysteresis comparator and a switching value collection and diagnosis processor. The transformer T1 is used for reducing the voltage of an alternating current power supply to a signal source of a safe voltage value, the first end of the signal source is connected with the diode D1 and the input end of the switch contact parallel circuit, the output end of the signal source connected with the diode D1 and the switch contact parallel circuit is connected with an upper bridge arm of the full-rectifier bridge, and the second end of the signal source is connected with a lower bridge arm of the full-rectifier bridge. The negative end of the full-rectifier bridge is grounded, the positive end of the full-rectifier bridge is input to the hysteresis comparator, the hysteresis comparator outputs to the switching value acquisition and diagnosis processor, and the switching value acquisition and diagnosis processor judges whether the external switch contact is switched off or switched on or a line is broken by acquiring waveforms. The method has the beneficial effects of high recognition accuracy and difficulty in interference.

Description

[Technical field]

[0001] The invention relates to the technical field of industrial and ship automation control, and in particular to a novel switch quantity signal collector for disconnection detection. [Background technology]

[0002] In automation control equipment, the disconnection detection function of the switch signal acquisition channel is very important, especially the acquisition channel involving safety functions, which must be designed with a disconnection diagnosis function. This ensures that once the switch channel loop is disconnected, the controller can detect and alarm in time to avoid failure to work properly when the safety protection function needs to be triggered due to failure of the detection loop.

[0003] At present, the switch disconnection detection function channel is generally designed using an analog signal acquisition channel. A resistor with a certain resistance is connected in parallel at the switch contact position, and a resistor with a certain resistance is connected in parallel at the analog acquisition channel. Different voltage division combinations are formed, and the three states of open, broken and closed of the switch channel can be identified through different voltage division values ​​of the analog acquisition channel.

[0004] The present invention aims at the technical problems that the existing disconnection detection switch quantity acquisition channel adopts analog quantity signal recognition with low accuracy and is easily interfered, and makes technical improvements to the switch quantity signal collector for disconnection detection. [Summary of the invention]

[0005] The purpose of the present invention is to provide a switch signal open circuit, closed circuit and disconnection detection collector which has high recognition accuracy and is not easily interfered with.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is a new type of switch signal collector for line break detection, which is used for disconnection, closure and line break detection of switch contacts of external automation control equipment connected in parallel with diode D1; it includes transformer T1, a full rectifier bridge composed of four diodes, a hysteresis comparator and a switch quantity acquisition diagnosis processor; the transformer T1 is used to step down the AC power supply to a signal source of a safe voltage value, the first terminal of the signal source is connected to the input end of the parallel circuit of the diode D1 and the switch contact, the output end of the signal source connected to the parallel circuit of the diode D1 and the switch contact is connected to the upper bridge arm of the full rectifier bridge, the second terminal of the signal source is connected to the lower bridge arm of the full rectifier bridge, the negative end of the full rectifier bridge is grounded, the positive end of the full rectifier bridge is input to the hysteresis comparator, the hysteresis comparator is output to the switch quantity acquisition diagnosis processor, and the switch quantity acquisition diagnosis processor determines whether the external switch contact is disconnected, closed, or the line is broken by collecting waveforms.

[0007] Preferably, the hysteresis comparator includes an operational amplifier U1 and resistors R1, R2, R3, R4, and R5. The negative end of the operational amplifier U1 is connected to the power supply through the resistor R3 and to the ground through the resistor R4. The positive end of the operational amplifier U1 is connected to the positive end of the full rectifier bridge through the resistor R1. The resistor R2 is connected across the positive end and the output end of the operational amplifier U1. The output end of the operational amplifier U1 is connected to the switch quantity acquisition and diagnosis processor through the resistor R5.

[0008] Preferably, in the novel switch quantity signal collector for disconnection detection, when the external switch contact is disconnected, the transformer T1 outputs alternating current, and only the positive half-cycle current signal of the alternating current passes through the diode D1 and the full rectifier bridge. The positive half-cycle current signal passes through the hysteresis comparator and then outputs a square wave signal to the switch quantity acquisition and diagnosis processor. The switch quantity acquisition and diagnosis processor confirms that the external switch contact is in the disconnected state at this time by identifying the square wave signal with the same frequency as the alternating current input.

[0009] Preferably, in the novel switch quantity signal collector for disconnection detection, when the external switch contact is closed, the transformer T1 outputs alternating current, the alternating current passes through the switch contact, the negative half-cycle current signal is flipped after passing through the full rectifier bridge, the positive half-cycle current signal and the flipped negative half-cycle current signal are output through the hysteresis comparator and then a square wave signal is output to the switch quantity acquisition diagnostic processor, and the switch quantity acquisition diagnostic processor confirms that the external switch contact is in a closed state at this time by identifying a square wave signal with a frequency twice that of the alternating current input.

[0010] Preferably, in the novel switch quantity signal collector for disconnection detection, when the external line is disconnected, the transformer T1 outputs alternating current, and the alternating current cannot be transmitted to the full rectifier bridge, the hysteresis comparator and the switch quantity acquisition diagnosis processor. The switch quantity acquisition diagnosis processor confirms that the line is in a disconnection fault state by failing to recognize any square wave signal.

[0011] The novel switch signal collector for disconnection detection of the present invention has the following beneficial effects: it can detect the switch state through the switch signal collection channel and can also identify whether a loop disconnection occurs, which is more economical and feasible than using an analog signal collection channel.

Brief Description of the Drawings

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0013] Figure 1This is a schematic diagram of a new type of switch signal collector for disconnection detection.

[0014] Figure 2 It is a new type of switch signal collector for disconnection detection, and a timing diagram of the signal waveform when the switch quantity is open.

[0015] Figure 3 It is a new type of switch signal collector for disconnection detection, and a timing diagram of the signal waveform when the switch is closed. [Specific implementation method]

[0016] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0017] On the contrary, the present invention covers any substitution, modification, equivalent method and scheme made on the essence and scope of the present invention as defined by the claims. Further, in order to make the public have a better understanding of the present invention, some specific details are described in detail in the detailed description of the present invention below. Those skilled in the art can fully understand the present invention without the description of these details.

[0018] Example 1

[0019] This embodiment realizes a new type of switch signal collector for disconnection detection.

[0020] This embodiment can detect the switch state through the switch signal acquisition channel and can also identify whether a loop is disconnected. Compared with using an analog signal acquisition channel, it is more economical and feasible.

[0021] Figure 1 This is a schematic diagram of a new type of switch signal collector for disconnection detection. Figure 1 As shown, the functional circuit of this embodiment is mainly divided into the following parts:

[0022] 1. The switch contact is the detected part, and a diode D1 is connected in parallel at the contact position;

[0023] 2. The signal source can reduce the 50Hz AC power supply to a safe voltage value of 9-32VAC that can be handled through transformer T1;

[0024] 3. The signal processing and acquisition part consists of a full-bridge rectifier circuit, a hysteresis comparator and a switch quantity acquisition channel, which serves as a signal acquisition processing and diagnosis circuit.

[0025] Specifically:

[0026] a) External switch contact disconnection status detection

[0027] Figure 2 This is a new type of switch signal collector for disconnection detection. The signal waveform timing diagram when the switch is open. Figure 2 As shown, the current flow direction and the corresponding output waveform in the detection circuit of this embodiment; transformer T1 outputs alternating current, and only the positive half cycle of the current can pass through D1, and the negative half cycle is cut off due to the unidirectional conduction characteristic of diode D1. The positive half cycle signal output by D1 passes through the full-bridge rectifier circuit, and similarly only the upper half cycle current signal is output. The current signal passing through the rectifier bridge outputs a square wave signal to the DI acquisition channel after passing through the hysteresis comparator. The DI acquisition channel confirms that the external switch is in the disconnected state at this time by identifying the square wave signal with the same frequency as the AC input.

[0028] b) External switch contact closure detection

[0029] Figure 3 This is a new type of switch signal collector for disconnection detection. The signal waveform timing diagram when the switch is closed. Figure 3 As shown, the current flow direction and the corresponding output waveform in the detection circuit of this embodiment; transformer T1 outputs alternating current, and at this time, diode D1 is bypassed by the switch contact. After the AC transformer T1 passes through the full-bridge rectifier circuit, the current in the lower half of the AC signal is reversed after passing through the rectifier bridge. After the current signal passes through the hysteresis comparator, it outputs a square wave signal to the DI acquisition channel. The DI acquisition channel recognizes a square wave signal with a frequency twice that of the AC input and confirms that the external switch is in a closed state at this time.

[0030] c) External line disconnection status detection

[0031] When the line is disconnected, the alternating current output by transformer T1 cannot be transmitted to the rectifier bridge and the back-end circuit. At this time, the DI acquisition channel cannot detect any square wave signal, and it is determined to be an external line disconnection fault.

[0032] In summary, the switch quantity signal acquisition function circuit with disconnection detection function is realized by combining the switch quantity detection channel with the above external circuit schematic components. Through the above circuit expansion, T1 can be reused as the AC signal input source of multiple channels to realize a multi-channel switch acquisition circuit with disconnection detection function.

[0033] A person skilled in the art can understand that all or part of the processes in the above-mentioned embodiments can be completed by instructing the relevant hardware through a computer program, and the program can be stored in a computer-readable storage medium, and when the program is executed, it can include the processes of the embodiments of the above-mentioned methods. The storage medium can be a disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM), etc.

[0034] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and supplements without departing from the principle of the present invention. These improvements and supplements should also be regarded as the scope of protection of the present invention.

Claims

1. A new type of switch signal collector for disconnection detection, used for disconnection, closing and line disconnection detection of the switch contacts of the external automation control equipment connected to the diode D1; its characteristics are: It includes a transformer T1, a full rectifier bridge composed of four diodes, a hysteresis comparator and a switch quantity acquisition and diagnosis processor; the transformer T1 is used to reduce the voltage of an AC power supply to a signal source of a safe voltage value, the first terminal of the signal source is connected to the input end of a parallel circuit of a diode D1 and a switch contact, the output end of the signal source connected to the parallel circuit of a diode D1 and a switch contact is connected to the upper bridge arm of the full rectifier bridge, the second terminal of the signal source is connected to the lower bridge arm of the full rectifier bridge, the negative end of the full rectifier bridge is grounded, the positive end of the full rectifier bridge is input to the hysteresis comparator, the hysteresis comparator is output to the switch quantity acquisition and diagnosis processor, and the switch quantity acquisition and diagnosis processor determines whether the external switch contact is open, closed, or the line is broken by collecting waveforms.

2. According to claim 1, the novel switch signal collector for disconnection detection is characterized in that: The hysteresis comparator includes an operational amplifier U1 and resistors R1, R2, R3, R4, and R5. The negative end of the operational amplifier U1 is connected to the power supply through the resistor R3 and to the ground through the resistor R4. The positive end of the operational amplifier U1 is connected to the positive end of the full rectifier bridge through the resistor R1. The resistor R2 is connected across the positive end and the output end of the operational amplifier U1. The output end of the operational amplifier U1 is connected to the switch quantity acquisition and diagnosis processor through the resistor R5.

3. The novel switch signal collector for disconnection detection according to claim 2 is characterized in that: When the external switch contact is disconnected, the transformer T1 outputs an alternating current, and only the positive half-cycle current signal of the alternating current passes through the diode D1 and the full rectifier bridge. The positive half-cycle current signal passes through the hysteresis comparator and outputs a square wave signal to the switch quantity acquisition and diagnosis processor. The switch quantity acquisition and diagnosis processor confirms that the external switch contact is in the disconnected state at this time by identifying the square wave signal with the same frequency as the alternating current input.

4. The novel switch signal collector for disconnection detection according to claim 2 is characterized in that: When the external switch contacts are closed, the transformer T1 outputs alternating current, the alternating current passes through the switch contacts, the negative half-cycle current signal is flipped after passing through the full rectifier bridge, the positive half-cycle current signal and the flipped negative half-cycle current signal are output as square wave signals to the switch quantity acquisition and diagnosis processor after passing through the hysteresis comparator, and the switch quantity acquisition and diagnosis processor confirms that the external switch contacts are in a closed state at this time by identifying a square wave signal with a frequency twice that of the alternating current input.

5. The novel switch signal collector for disconnection detection according to claim 2 is characterized in that: When the external line is broken, the transformer T1 outputs alternating current, and the alternating current cannot be transmitted to the full rectifier bridge, the hysteresis comparator and the switch quantity acquisition diagnosis processor. The switch quantity acquisition diagnosis processor confirms that the line is broken by failing to recognize any square wave signal.

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