Pulse signal acquisition circuit and distributed control system
By designing a vein signal collection circuit with a switching signal type, the problem of unable to be compatible with the existing technology cannot be compatible with dry contacts and wet contact signals, realize high -precision signal acquisition, and improve the efficiency and cost benefits of the collection circuit.
Patent Information
- Application Number
- CN202411357673.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-27
- Publication Date
- 2025-01-28
AI Technical Summary
The prior art cannot be compatible with both dry contact and wet contact pulse signals, and most measurement modules on the market cannot meet the requirements for high precision in the industrial control field.
The collection circuit of a pulse signal is designed. The circuit can switch the collection signal type by changing the wiring method of the local device signal line and the signal receiving port, supports two signal input methods: dry contact and wet contact. The circuit includes signal receiving ports, sampling circuits and built -in power supply, and can be selected including protective circuits, control modules and isolation circuits.
A single collection circuit is compatible with the compatibility of dry contact and wet contact signals, improves the efficiency and accuracy of the collection circuit, and saves material and labor costs.
Smart Images
Figure CN119376300A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to the field of circuit technology, and in particular to a pulse signal acquisition circuit and a distributed control system. Background Art
[0002] The distributed control system (DCS) includes various IO data acquisition modules and data packet receiving and sending modes. The pulse input module (PI) in the IO data acquisition module is used to collect pulse signals sent by local equipment, and the pulse signal is usually a positive pulse with an amplitude not exceeding 24V. The local equipment can be divided into dry contact type and wet contact type according to the output signal type, but a single IO module in many distributed control systems can only adapt to a single type of signal. For some power plants that have been in operation for a long time, when they are being renovated and overhauled, replacing new equipment will cause signal type incompatibility or wiring difficulties. At the same time, in the field of industrial control, the use scenario of the pulse acquisition module requires it to have high measurement accuracy. Usually, the pulse signal frequency range of field equipment such as rotary flowmeters and control servo motors is 0.1 to 20KHZ, and most of the measurement modules on the market cannot meet its accuracy requirements. Summary of the invention
[0003] The technical problem to be solved by the present disclosure is to overcome the defect in the prior art that dry contact and wet contact types cannot be compatible at the same time when collecting pulse signals, and to provide a pulse signal collection circuit and a distributed control system.
[0004] The present invention solves the above technical problems through the following technical solutions:
[0005] In a first aspect, a pulse signal acquisition circuit is provided, the acquisition circuit comprising a signal receiving port, a sampling circuit and a built-in power supply; the signal receiving port comprises a first terminal, a second terminal and a third terminal;
[0006] The second terminal is connected to the input end of the sampling circuit, and the output end of the sampling circuit and the first terminal are both grounded;
[0007] The second terminal is connected to the input end of the sampling circuit, the third terminal is connected to the positive electrode of the built-in power supply, and the negative electrode of the built-in power supply and the output end of the sampling circuit are both grounded;
[0008] In the wet contact mode, the first terminal is used to connect to the negative electrode of the local device signal line, and the second terminal is used to connect to the positive electrode of the local device signal line;
[0009] In the dry contact mode, the second terminal is used to connect to the negative pole of the local device signal line, and the third terminal is used to connect to the positive pole of the local device signal line.
[0010] Optionally, the acquisition circuit further includes a protection circuit, and the protection circuit is arranged between the signal receiving port and the sampling circuit.
[0011] Optionally, the sampling circuit includes a sampling resistor, a current detection amplifier, a hysteresis comparator and a voltage follower;
[0012] The sampling resistor, the current detection amplifier, the hysteresis comparator and the voltage follower are connected in sequence.
[0013] Optionally, the acquisition circuit also includes a first control module; the input end of the first control module is connected to the output end of the sampling circuit, and the first control module is used to count the pulse signal output by the sampling circuit within one second to obtain the number of pulses, and to obtain the pulse period by monitoring the signal edge of the pulse signal output by the sampling circuit.
[0014] Optionally, the acquisition circuit further includes a second control module; an input end of the second control module is connected to an output end of the first control module, and the second control module is used to calculate the frequency of the pulse signal according to the number of pulses and the pulse period.
[0015] Optionally, the acquisition circuit further includes an isolation circuit; the isolation circuit is arranged between the sampling circuit and the first control module.
[0016] Optionally, the isolation circuit includes a digital isolation chip.
[0017] Optionally, the acquisition circuit further includes a communication circuit and a host computer; the second control module is connected to the host computer via the communication circuit, and the host computer is used to receive the frequency of the pulse signal output by the second control module.
[0018] Optionally, there are at least two signal receiving ports and at least two sampling circuits, the signal receiving ports correspond one to one with the sampling circuits, and the output ends of the sampling circuits are connected to the input ends of the first control module.
[0019] In a second aspect, a distributed control system is provided, wherein the control system includes the pulse signal acquisition circuit as described in the first aspect.
[0020] On the basis of being in accordance with the common sense in the art, the above-mentioned optional conditions can be arbitrarily combined to obtain the preferred embodiments of the present disclosure.
[0021] The positive and progressive effect of the present disclosure is that the type of collected signals can be switched by changing the wiring method of the local equipment signal line and the signal receiving port, so that a single collection circuit supports two different signal input methods of dry contact and wet contact, thereby improving the use efficiency of the collection circuit. When the signal type of the local equipment changes, only the wiring method between the local equipment and the signal receiving port needs to be changed to complete the signal collection of the local equipment, thus saving the material cost of the signal receiving port and the labor cost of the on-site construction personnel. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 A schematic diagram of a pulse signal acquisition circuit structure provided in Embodiment 1 of the present disclosure;
[0023] Figure 2 A wet contact mode connection diagram of a pulse signal acquisition circuit provided in Example 1 of the present disclosure;
[0024] Figure 3 A dry contact mode connection diagram of a pulse signal acquisition circuit provided in Embodiment 1 of the present disclosure;
[0025] Figure 4 A schematic diagram of module connections of a pulse signal acquisition circuit provided in Embodiment 1 of the present disclosure;
[0026] Figure 5 A schematic diagram of a structure including two signal receiving ports and two sampling circuits provided in Embodiment 1 of the present disclosure;
[0027] Figure 6 A schematic diagram of module connection including two signal receiving ports and two sampling circuits provided in Embodiment 1 of the present disclosure. DETAILED DESCRIPTION
[0028] The present disclosure is further described below by way of examples, but the present disclosure is not limited to the scope of the examples.
[0029] Prefixes such as "first" and "second" are used in the embodiments of the present disclosure only to distinguish different description objects, and have no limiting effect on the position, order, priority, quantity or content of the described objects. The use of prefixes such as ordinal numbers to distinguish description objects in the embodiments of the present disclosure does not constitute a limitation on the described objects. For the statement of the described objects, please refer to the description in the context of the claims or embodiments, and no unnecessary limitation should be constituted due to the use of such prefixes. In addition, in the description of the present embodiment, unless otherwise specified, the meaning of "plurality" is two or more.
[0030] In the embodiments of the present disclosure, the collection, storage, use, processing, transmission, provision and disclosure of user personal information involved are in compliance with the provisions of relevant laws and regulations and do not violate public order and good morals.
[0031] Example 1
[0032] This embodiment provides a pulse signal acquisition circuit, such as Figure 1 As shown, the acquisition circuit includes a signal receiving port 101, a sampling circuit 102 and a built-in power supply 103; the signal receiving port includes a first terminal S1-, a second terminal S1+ and a third terminal E1+; the second terminal S1+ is connected to the input end of the sampling circuit 102, and the output end of the sampling circuit 102 and the first terminal S1- are both grounded; the second terminal S1+ is connected to the input end of the sampling circuit, the third terminal E1+ is connected to the positive electrode of the built-in power supply 103, and the negative electrode of the built-in power supply 103 and the output end of the sampling circuit 102 are both grounded;
[0033] In the wet contact mode, the first terminal is used to connect to the negative pole of the local equipment signal line, and the second terminal is used to connect to the positive pole of the local equipment signal line; in the dry contact mode, the second terminal is used to connect to the negative pole of the local equipment signal line, and the third terminal is used to connect to the positive pole of the local equipment signal line.
[0034] In the specific implementation, see Figure 1 There are two connection loops in the acquisition circuit. In the first loop, the second terminal S1+ is connected to the input of the sampling circuit 102, and the output of the sampling circuit 102 and the first terminal S1- are both grounded; in the second loop, the second terminal S1+ is connected to the input of the sampling circuit 102, and the third terminal E1+ is connected to the positive electrode of the built-in power supply 103, and the negative electrode of the built-in power supply 103 and the output of the sampling circuit 102 are both grounded. The wet contact mode usually refers to the case of processing charged signals, and the dry contact mode usually refers to the case of processing uncharged signals. In the wet contact mode, Figure 2 As shown, the first terminal S1- is used to connect to the negative electrode of the signal line of the local device 104, and the second terminal S1+ is used to connect to the positive electrode of the signal line of the local device 104, and at this time, it will be connected to the first loop in the acquisition circuit, so as to realize the acquisition of the charged pulse signal; in the dry contact mode, as Figure 3As shown, the second terminal S1+ is used to connect to the negative pole of the signal line of the local device 104, and the third terminal E1+ is used to connect to the positive pole of the signal line of the local device 104, and at this time it will be connected to the second loop in the acquisition circuit, so as to realize the acquisition of the non-electric pulse signal. By changing the wiring method of the local device signal line and the signal receiving port, the acquisition signal type can be switched, so that a single acquisition circuit supports two different signal input methods of dry contact and wet contact. Specifically, the built-in power supply can be a 24V power supply, which can provide the required power for the passive pulse quantity local device in the wet contact mode, and in the dry contact mode, the pulse signal is provided by the local device, and the acquisition circuit does not need to provide additional power.
[0035] In an optional implementation, the acquisition circuit further includes a protection circuit, and the protection circuit is arranged between the signal receiving port and the sampling circuit.
[0036] In the specific implementation, Figure 4 As shown, by providing a protection circuit 105 between the signal receiving port and the sampling circuit, the quality of the signal received by the sampling circuit is ensured, thereby improving the performance and reliability of the entire acquisition circuit.
[0037] In a specific example, the protection circuit includes a TVS diode and a fuse, wherein the TVS diode can protect the circuit from high voltage transients, and the fuse is used as an overcurrent protection. When the current exceeds the rated value, the fuse will melt, thereby cutting off the circuit and protecting the circuit from further damage. The combination of the TVS diode and the fuse provides dual protection against voltage and current anomalies. In another specific example, the protection circuit also includes a filter capacitor and a magnetic bead. The filter capacitor can remove high-frequency noise in the circuit, and the magnetic bead can be used to suppress high-frequency interference. The combination of the filter capacitor and the magnetic bead can provide noise suppression in a wide frequency range, thereby improving the clarity and quality of the signal.
[0038] In an optional implementation, the sampling circuit includes a sampling resistor, a current detection amplifier, a hysteresis comparator and a voltage follower; the sampling resistor, the current detection amplifier, the hysteresis comparator and the voltage follower are connected in sequence.
[0039] In a specific implementation, a sampling resistor is used to generate a voltage drop in a circuit so that subsequent circuits can detect current. The selection of a sampling resistor requires a balance between voltage drop and power consumption. A sampling resistor that is too small may not generate enough voltage drop, while a sampling resistor that is too large may introduce excessive power consumption. A current detection amplifier can amplify the tiny voltage drop on the sampling resistor to a level that is easier to handle, ensuring that subsequent circuits can accurately read current information. A hysteresis comparator has two different threshold voltages, which are used to trigger high and low level outputs, respectively. By setting hysteresis, the output state changes only when the input signal exceeds a certain threshold value, thereby reducing errors caused by noise or environmental changes. A voltage follower is often called a buffer or unity gain amplifier, which converts the high output impedance of the hysteresis comparator into a low output impedance, and can drive larger loads or longer transmission distances without losing signal quality, thereby ensuring signal integrity.
[0040] In a specific example, the two threshold voltages of the hysteresis comparator are set to 9V and 16V respectively. When the amplitude of the input pulse signal exceeds 16V, the output of the hysteresis comparator will become a high level; when the amplitude of the input pulse signal drops below 9V, the output of the hysteresis comparator will become a low level; and when the amplitude of the input pulse signal is between these two thresholds, the hysteresis comparator will not change its output state, that is, if the output was high before, it will maintain the output high level, and if the output was low before, it will maintain the output low level.
[0041] In an optional embodiment, the acquisition circuit also includes a first control module; the input end of the first control module is connected to the output end of the sampling circuit, and the first control module is used to count the pulse signal output by the sampling circuit within one second to obtain the number of pulses, and to obtain the pulse period by monitoring the signal edge of the pulse signal output by the sampling circuit.
[0042] In the specific implementation, Figure 4 As shown, the input end of the first control module 106 receives the pulse signal output from the sampling circuit, and counts the number of pulse signals within the set time of 1 second. In addition to the counting function, the first control module can also measure the number of clock cycles occupied by a single pulse by monitoring the rising edge or falling edge of the pulse signal, and then calculate the pulse period of the pulse signal according to the clock period. Specifically, FPGA can be used as the first control module. When the rising edge of the pulse signal is detected, the current clock counter value is read. When the next corresponding rising edge is detected, the clock counter value is read again. The difference between the two readings is recorded as the number of clock cycles n, and then the pulse period T can be calculated by the formula T=n×t, where t represents the time length of each clock cycle.
[0043] In an optional embodiment, the acquisition circuit also includes a second control module; the input end of the second control module is connected to the output end of the first control module, and the second control module is used to calculate the frequency of the pulse signal according to the number of pulses and the pulse period.
[0044] In the specific implementation, Figure 4 As shown, after the second control module 107 receives the number of pulses and the pulse period output from the first control module, it will identify and calculate the frequency of the pulse signal according to the number of pulses, and different frequency calculation methods will be used for different numbers of pulses. Specifically, if the number of pulses is less than 1, that is, the number of pulses occurring in one second is less than one, this indicates that the frequency of the pulse signal is lower than 1Hz. In this case, the second control module will use the reciprocal of the pulse period as the frequency of the pulse signal; if the number of pulses is greater than 1, this means that the number of clock cycles occupied by a single pulse signal is relatively small, which may cause a large measurement error, so the second control module will use the number of pulses as the frequency of the pulse signal. For signals with lower frequencies, the reciprocal of the pulse period is used to calculate the frequency, while for signals with higher frequencies, the number of pulses is directly used as the frequency value, thereby improving the accuracy of pulse signal acquisition. In a specific example, a microcontroller (MCU) can be used as the second control module to calculate the frequency of the pulse signal.
[0045] In an optional implementation, the acquisition circuit further includes an isolation circuit; the isolation circuit is arranged between the sampling circuit and the first control module.
[0046] In the specific implementation, Figure 4 As shown, the isolation circuit 108 can prevent high voltage and current from being transmitted from the sampling circuit to the first control module, thereby protecting the first control module from electrical damage. The isolation circuit can also reduce the impact of electromagnetic, radio frequency and other noise interference on signal transmission, ensuring the clarity and accuracy of the signal. By setting an isolation circuit between the sampling circuit and the first control module, the stability and safety of the pulse signal during transmission can be ensured, while improving the anti-interference ability of the entire acquisition circuit.
[0047] In an optional implementation, the isolation circuit includes a digital isolation chip.
[0048] In specific implementation, the digital isolation chip is a semiconductor device used to provide electrical isolation, which can protect the circuit from damage by high voltage and current and reduce electromagnetic interference. At the same time, the digital isolator also has the advantages of low power consumption, small size and high reliability. Specifically, the digital isolation chip of ISO7021 or ISO7842 model can be selected.
[0049] In an optional implementation, the acquisition circuit further includes a communication circuit and a host computer; the second control module is connected to the host computer via the communication circuit, and the host computer is used to receive the frequency of the pulse signal output by the second control module.
[0050] In the specific implementation, Figure 4 As shown, the communication circuit 109 is responsible for establishing a communication connection between the second control module and the host computer 110, and transmitting the pulse signal frequency calculated by the second control module to the host computer. The host computer is usually a computing platform, such as a personal computer, a workstation or an industrial PC, which can run specific software to receive, display and store signal data from the second control module. The second control module is the core module for analyzing the pulse signal. It establishes a connection relationship with the host computer through the communication circuit to ensure effective management and control of the pulse signal data, thereby realizing real-time monitoring of the pulse signal. Specifically, the communication circuit usually includes an Ethernet PHY chip unit and a network interface. By combining the Ethernet PHY chip unit and the network interface, the communication circuit can achieve high-speed and reliable data transmission.
[0051] In an optional implementation, there are at least two signal receiving ports and at least two sampling circuits, the signal receiving ports correspond one to one with the sampling circuits, and the output ends of the sampling circuits are connected to the input ends of the first control module.
[0052] In a specific implementation, the acquisition circuit includes multiple signal receiving ports and multiple sampling circuits, wherein each signal receiving port is connected to a corresponding sampling circuit, and then the output ends of all sampling circuits are collectively connected to the input end of the first control module. Since multiple signal receiving ports and corresponding sampling circuits can work in parallel and process multiple signal sources at the same time, the data processing capability and efficiency of the acquisition circuit are improved, and each signal receiving port and sampling circuit can be regarded as an independent module, which is convenient for maintenance and upgrading. If a module has a problem, it will not affect the normal operation of other modules. Finally, the output ends of all sampling circuits are connected to the first control module, which is also convenient for centralized control and data processing of the acquisition circuit.
[0053] In a specific example, Figure 5As shown, the acquisition circuit includes a first signal receiving port 501, a second signal receiving port 502, a first sampling circuit 503 and a second sampling circuit 504, wherein the first signal receiving port is connected to the input end of the first sampling circuit, the second signal receiving port is connected to the input end of the second sampling circuit, the output end of the first sampling circuit and the output end of the second sampling circuit are both connected to the first control module 505, when the local device outputs an active signal, the sampling circuit is correspondingly connected to the wet contact mode, when the local device outputs a passive signal, the sampling circuit is correspondingly connected to the dry contact mode, so that the pulse signal with power and the pulse signal without power can be collected at the same time in the acquisition circuit, thereby improving the working efficiency of the acquisition circuit.
[0054] In another specific example, the first control module is an FPGA, and the second control module is an MCU. Figure 6 As shown, a first protection circuit 507 is set between the first signal receiving port 501 and the first sampling circuit 503, a second protection circuit 508 is set between the second signal receiving port 502 and the second sampling circuit 504, a first isolation circuit 509 is set between the first sampling circuit 503 and the FPGA 506, and a second isolation circuit 510 is set between the second sampling circuit 504 and the FPGA 506. The output end of the FPGA is connected to the input end of the MCU 511, and the MCU establishes a connection with the host computer 513 through the communication module 512.
[0055] In this embodiment, the type of collected signal can be switched by changing the wiring method with the signal receiving port, so that a single collection circuit supports two different signal input methods, dry contact and wet contact, thereby improving the utilization efficiency of the collection circuit. When the signal type of the local equipment changes, it is only necessary to change the wiring method with the signal receiving port to complete the signal collection of the local equipment, thereby saving the material cost of the signal receiving port and the labor cost of on-site construction personnel.
[0056] Example 2
[0057] This embodiment provides a distributed control system, and the control system includes the pulse signal acquisition circuit as described in Example 1.
[0058] In this embodiment, the distributed control system can collect pulse signals of different signal types output by local equipment.
[0059] Although the specific embodiments of the present disclosure are described above, those skilled in the art should understand that this is only an example, and the protection scope of the present disclosure is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present disclosure, but these changes and modifications all fall within the protection scope of the present disclosure.
Claims
1. A pulse signal acquisition circuit, characterized in that: The acquisition circuit includes a signal receiving port, a sampling circuit and a built-in power supply; the signal receiving port includes a first terminal, a second terminal and a third terminal; The second terminal is connected to the input end of the sampling circuit, and the output end of the sampling circuit and the first terminal are both grounded; The second terminal is connected to the input end of the sampling circuit, the third terminal is connected to the positive electrode of the built-in power supply, and the negative electrode of the built-in power supply and the output end of the sampling circuit are both grounded; In the wet contact mode, the first terminal is used to connect to the negative electrode of the local device signal line, and the second terminal is used to connect to the positive electrode of the local device signal line; In the dry contact mode, the second terminal is used to connect to the negative pole of the local device signal line, and the third terminal is used to connect to the positive pole of the local device signal line.
2. The acquisition circuit according to claim 1, characterized in that: The acquisition circuit further includes a protection circuit, and the protection circuit is arranged between the signal receiving port and the sampling circuit.
3. The acquisition circuit according to claim 1, characterized in that: The sampling circuit includes a sampling resistor, a current detection amplifier, a hysteresis comparator and a voltage follower; The sampling resistor, the current detection amplifier, the hysteresis comparator and the voltage follower are connected in sequence.
4. The acquisition circuit according to claim 1, characterized in that: The acquisition circuit also includes a first control module; The input end of the first control module is connected to the output end of the sampling circuit. The first control module is used to count the pulse signal output by the sampling circuit within one second to obtain the number of pulses, and to obtain the pulse period by monitoring the signal edge of the pulse signal output by the sampling circuit.
5. The acquisition circuit as claimed in claim 4, characterized in that: The acquisition circuit also includes a second control module; The input end of the second control module is connected to the output end of the first control module, and the second control module is used to calculate the frequency of the pulse signal according to the number of pulses and the pulse period.
6. The acquisition circuit according to claim 4, characterized in that: The acquisition circuit also includes an isolation circuit; The isolation circuit is arranged between the sampling circuit and the first control module.
7. The acquisition circuit according to claim 6, characterized in that: The isolation circuit includes a digital isolation chip.
8. The acquisition circuit according to claim 5, characterized in that: The acquisition circuit also includes a communication circuit and a host computer; The second control module is connected to the host computer via the communication circuit, and the host computer is used to receive the frequency of the pulse signal output by the second control module.
9. The acquisition circuit according to claim 4, characterized in that: There are at least two signal receiving ports and at least two sampling circuits. The signal receiving ports correspond to the sampling circuits one by one, and the output ends of the sampling circuits are connected to the input ends of the first control module.
10. A distributed control system, characterized in that: The control system comprises a pulse signal acquisition circuit as claimed in any one of claims 1 to 9.