Control circuit board capable of accurately acquiring analog quantity
By using a three-channel precision analog signal acquisition control circuit board with high-precision operational amplifier modules, filtering circuits, and isolation modules, the problem of inaccurate signals on the analog signal acquisition circuit board was solved, achieving high-precision and stable signal acquisition and transmission.
Patent Information
- Application Number
- CN202520189521.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-07
- Publication Date
- 2025-12-23
- Estimated Expiration
- 2035-02-07
AI Technical Summary
Existing analog signal acquisition circuit boards are not designed to achieve accurate and stable signal acquisition and are easily affected by external interference, resulting in inaccurate signals.
The precision analog signal acquisition control circuit board adopts a three-channel design, including a high-precision operational amplifier module, a filter circuit, an isolation power supply module, and a signal isolation module. Combined with a four-layer PCB motherboard design, it ensures signal stability and accuracy.
It achieves high precision and stability in signal acquisition, with an accuracy of 0.1%. It can stably acquire and output signals in different industrial environments, reduce external interference, and ensure accurate signal transmission.
Smart Images
Figure CN223712048U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of circuit board technology, specifically to a circuit board for accurately acquiring analog quantities. Background Technology
[0002] Analog signal acquisition circuit boards are key components used to acquire analog signals. In industrial automation and process control, 4-20mA signals are favored as stable signals for information transmission, making accurate signal acquisition crucial. In practical applications, analog signal acquisition circuit boards primarily convert the acquired 4-20mA signals into actual numerical values and send them to the user, who can then perform corresponding control processing based on these values.
[0003] Conventional data acquisition circuit boards acquire voltage and current signals simultaneously to support more functions. Therefore, they often use relatively inexpensive chips and lack proper circuit optimization, potentially leading to inaccuracies during or after use. To address this, designers in this field have developed a circuit board for accurate and stable analog signal acquisition. Utility Model Content
[0004] The technical problem solved by this utility model is to provide a control circuit board for precise acquisition of analog quantities through three channels.
[0005] The technical solution adopted by this utility model to solve its technical problem is: a control circuit board for accurately acquiring analog quantities, characterized in that: it includes a PCB motherboard, a main control chip installed in the center of the PCB motherboard, a signal acquisition module installed on the right side of the main control chip, a signal output module installed on the left side of the main control chip, and a DC-DC power supply module; it also includes a first high-precision operational amplifier module installed between the main control chip and the signal acquisition module, wherein the signal acquisition module is electrically connected to the first high-precision operational amplifier module, and the first high-precision operational amplifier module is electrically connected to the main control chip.
[0006] Furthermore, it also includes a second high-precision operational amplifier module, wherein the output pin of the signal acquisition module is electrically connected to the input pin of the second high-precision operational amplifier module, and the output pin of the second high-precision operational amplifier module is electrically connected to the input pin of the main control chip.
[0007] Furthermore, it also includes an isolated power supply module to prevent power fluctuations caused by signal interference.
[0008] Furthermore, it also includes a 485 chip and a signal isolation module, wherein the output pin of the 485 chip is electrically connected to the input pin of the signal isolation module, and the output pin of the signal isolation module is electrically connected to the input pin of the main control chip.
[0009] Furthermore, a filter circuit is also provided between the first high-precision operational amplifier module and the main control chip.
[0010] Furthermore, a filter circuit is also provided between the second high-precision operational amplifier module and the main control chip.
[0011] The beneficial effects of this invention are as follows: To avoid the impact of too many functions on circuit acquisition, the control circuit board of this invention is designed to acquire current signals through three channels. A 1.5MHz, high-precision (1uV), rail-to-rail precision operational amplifier is used for signal acquisition, achieving an accuracy of 0.1%. The low temperature drift characteristic allows the circuit board to stably acquire and output signals in various industrial environments. The PCB motherboard uses a 4-layer design, which reduces external interference during signal processing and ensures the stability of the acquired signals.
[0012] This invention provides power to the 485 chip via an isolated power supply module, and transmits the 485 chip signals through a signal isolation module to ensure that the signal section is not affected by external interference. The test data can be sent to the user in real time via the standard Modbus RTU protocol. Attached Figure Description
[0013] Figure 1 This is a schematic diagram of the structure of this utility model.
[0014] The components in the diagram are labeled as follows: 1. PCB motherboard; 2. Signal acquisition module; 3. Main control chip; 4. Signal output module; 5. First high-precision operational amplifier module; 6. Second high-precision operational amplifier module; 7. Isolation power supply module; 8. 485 chip; 9. Signal isolation module. Detailed Implementation
[0015] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.
[0016] like Figure 1The control circuit board shown for precise analog signal acquisition includes a PCB motherboard 1. The PCB motherboard 1 employs a 4-layer design to minimize external interference during signal processing and ensure the stability of the acquired signal. A main control chip 3 is mounted at the center of the PCB motherboard 1. A signal acquisition module 2 is mounted to the right of the main control chip 3, and a signal output module 4 is mounted to the left of the main control chip 3. A DC-DC power supply module is also installed to provide power. This DC-DC power supply module uses a wide voltage input, supporting input voltages of 4.5V-40V and can stably output 5V. A first high-precision operational amplifier module 5 is also included, installed between the main control chip 3 and the signal acquisition module 2. The output pin of the signal acquisition module 2 is electrically connected to the input pin of the first high-precision operational amplifier module 5, and the output pin of the first high-precision operational amplifier module 5 is electrically connected to the input pin of the main control chip 3. A second high-precision operational amplifier module 6 is also included. The output pin of the signal acquisition module 2 is electrically connected to the input pin of the second high-precision operational amplifier module 6, and the output pin of the second high-precision operational amplifier module 6 is electrically connected to the input pin of the main control chip 3. In this embodiment, three 4-20mA signal acquisition channels are configured. After input to signal acquisition module 2, the analog signal is converted into a voltage signal through a high-precision resistor sampling circuit. Two of these signals are connected to pins 3 and 5 of the first high-precision operational amplifier module 5, respectively. After the voltage signal is input to the first high-precision operational amplifier module 5, it passes through the high-precision operational amplifier and then passes through a negative feedback circuit to obtain a more stable voltage signal, which reduces signal interference. A filtering circuit is also provided between the first high-precision operational amplifier module 5 and the main control chip 3. After passing through the filtering circuit, the stabilized signal is input to the input pin of the main control chip 3. The main control chip 3 supports 12-bit ADC acquisition, and after algorithm optimization, the accuracy can reach 0.1%.
[0017] Based on the above, the third signal acquisition is the output pin of the signal acquisition module 2 and pin 3 of the second high-precision operational amplifier module 6. After the voltage signal is input to the second high-precision operational amplifier module 6, it passes through the high-precision operational amplifier and then obtains a more stable voltage signal through the negative feedback circuit. The negative feedback circuit can reduce signal interference. A filter circuit is also provided between the second high-precision operational amplifier module 6 and the main control chip 3. After passing through the filter circuit, the stabilized signal is input to the input pin of the main control chip 3.
[0018] In industrial environments, signal interference can occur during operation, causing power fluctuations that can affect signal acquisition and transmission. To avoid power fluctuations caused by signal interference, an isolation power supply module 7 is installed. A 485 chip 8 and a signal isolation module 9 are also included. The output pins of the 485 chip 8 are electrically connected to the input pins of the signal isolation module 9, and the output pins of the signal isolation module 9 are electrically connected to the input pins of the main control chip 3. The communication signals from the isolation power supply module 7 and the 485 chip 8 are connected to the two input pins of the signal isolation module 9 through two paths. After isolation by the signal isolation module 9, the communication signals are transmitted to the input pins of the main control chip 3 through the output pins of the signal isolation module 9, thus enabling stable communication.
[0019] In addition, some components such as resistors and capacitors required for the operation of the circuit were also installed.
[0020] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this utility model. It should be understood that the above descriptions are merely specific embodiments of this utility model and are not intended to limit this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.
Claims
1. A control circuit board for accurately acquiring analog signals, characterized in that: It includes a PCB motherboard, a main control chip installed in the center of the PCB motherboard, a signal acquisition module installed to the right of the main control chip, a signal output module installed to the left of the main control chip, and a DC-DC power supply module; it also includes a first high-precision operational amplifier module installed between the main control chip and the signal acquisition module, wherein the signal acquisition module is electrically connected to the first high-precision operational amplifier module, and the first high-precision operational amplifier module is electrically connected to the main control chip.
2. The control circuit board for accurately acquiring analog quantities as described in claim 1, characterized in that: It also includes a second high-precision operational amplifier module, wherein the output pin of the signal acquisition module is electrically connected to the input pin of the second high-precision operational amplifier module, and the output pin of the second high-precision operational amplifier module is electrically connected to the input pin of the main control chip.
3. The control circuit board for accurately acquiring analog quantities as described in claim 2, characterized in that: It also includes an isolated power supply module to prevent power fluctuations caused by signal interference.
4. The control circuit board for accurately acquiring analog quantities as described in claim 3, characterized in that: It also includes a 485 chip and a signal isolation module. The output pin of the 485 chip is electrically connected to the input pin of the isolation module, and the output pin of the isolation module is electrically connected to the input pin of the main control chip.
5. The control circuit board for accurately acquiring analog quantities as described in claim 1, characterized in that: A filter circuit is also provided between the first high-precision operational amplifier module and the main control chip.
6. The control circuit board for accurately acquiring analog quantities as described in claim 2, characterized in that: A filter circuit is also provided between the second high-precision operational amplifier module and the main control chip.