Centrifuge linear distortion correction method based on WIA-FA wireless communication

Abstract

The application discloses a centrifuge linear distortion correction method based on WIA-FA wireless communication, and the PID mode is adopted to form a closed loop control by using a frequency converter speed regulation and a Hall sensor speed measurement in centrifugal equipment design. By further optimizing the algorithm, the influence of the linear distortion of the control link on the system is eliminated, the problem that the set value deviates from the actual value is solved, the simulation loop is corrected by implementing the broken line fitting mode, and the control precision and the control performance are effectively improved. When metering, analog calibration is changed into digital calibration, and operation becomes simple. The centrifuge is provided with a WIA-FA communication module, the WIA-FA communication module is used for connecting the centrifuge to a WIA-FA wireless network, working parameters and result records are transmitted through the WIA-FA wireless network, data security can be realized, and leakage of secret data is avoided.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, and more specifically to a method for correcting linear distortion in centrifuges. Background Technology

[0002] In the field of military semiconductor manufacturing, centrifuges are used to inspect the mechanical properties of chips, including whether the welding of metal cover plates and the firmness of die bonding meet the relevant national military standards. They also test the strength of the chip casing itself, using visual inspection, helium mass spectrometry leak detection, and functional testing to identify problems and ensure product quality. Centrifuges used in semiconductor manufacturing require high precision in their processes; a crucial indicator is speed control and maintenance, including the acceleration and deceleration processes, which directly affect quality and efficiency.

[0003] Centrifuges typically consist of: a mechanical frame, a vacuum chamber, a rotating disc, and a cooling system. The rotating disc is a fixed component that rotates under the drive of a speed-regulating motor, providing and adjusting its position. Upon startup, the vent valve automatically closes, and a mechanical pump draws a vacuum. A vacuum level of 10⁻¹ Pa is sufficient; too high a level results in a longer evacuation time, while too low a level increases air resistance and affects acceleration. Once the vacuum reaches the set threshold, the motor starts and maintains the set speed for 1 minute before deceleration begins. First, the vent valve opens, allowing the chamber to enter the atmosphere. Simultaneously, the braking resistor is activated; both actions contribute to deceleration. The braking resistor also releases recoil energy to protect the inverter's DC bus. The centrifuge is a hazardous device; the chamber door automatically locks before the operating speed reaches zero. Due to the ultra-high-speed rotation, the turntable must maintain dynamic balance; therefore, a dynamic balance detection device and an emergency stop switch are installed, providing both automatic and manual solutions for emergencies. Furthermore, there is a constraint between the number of chambers and the placement of components; roughly speaking, symmetrical placement is required. Improper placement or component damage can generate strong noise and vibration, which, if left unchecked, can easily lead to machine damage and personal injury.

[0004] According to national military standards, centrifuges require regular metrological calibration. This has two meanings: First, at a certain result point, the deviation around the center position needs to be measured to determine whether it is qualified. The cause is determined by the machine's inherent algorithm and the accuracy of the components. Second, the degree of deviation between this specific point and the set value needs to be calibrated. Often, centrifuges cannot achieve complete alignment of multiple points, especially with traditional range adjustment and zero-point offset methods. Often, the two ends are aligned but the middle is not. This is caused by distortion in some linear components, such as D / A, A / D, thyristors, and sensors. Compared to the former, this deviation is more common and has more serious consequences. Because the inability to align is considered an error in metrology, some centrifuges often exceed tolerances due to the superposition of these two points, even leading to premature scrapping. An alternative method is to limit the range and only focus on one end to achieve partial alignment, which in turn reduces the performance of the equipment. Traditional designs overly rely on the linear characteristics of devices. When distortion occurs, they can only resort to analog methods, primarily adjusting the range and zero point. This limited approach results in mutually coupled and restrictive adjustments, often failing to achieve the desired outcome. Furthermore, military semiconductor production often involves information security, and the transmission of centrifuge operating data via Wi-Fi wireless networks poses a risk of data leakage. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a centrifuge linear distortion correction method based on WIA-FA wireless communication. This method solves the problems of existing technologies, which mainly rely on range adjustment and zero point adjustment, resulting in limited and singular means, coupled and mutually restrictive adjustment effects, and the inconvenience of transmitting centrifuge operating data via Wi-Fi wireless network.

[0006] This invention provides a method for correcting linear distortion in centrifuges based on WIA-FA wireless communication, comprising:

[0007] The centrifuge acquires pulse signals by using three magnetic bodies evenly distributed at a 120-degree angle on the motor rotor. A Hall effect switch with magnetic sensitivity is used for sensing, and three pulse signals are generated for each revolution of the motor. The centrifuge has a WIA-FA communication module, which is used to connect the centrifuge to the WIA-FA wireless network and transmit working parameters and result records through the WIA-FA wireless network.

[0008] The pulse signal is amplified, shaped, and filtered to remove glitches and background interference.

[0009] The instantaneous speed of the motor is obtained by counting the pulse signals within the sampling period and converting them.

[0010] The digital signal representing the rotational speed is converted into a 0-5V analog signal by a D / A chip, and then conditioned to 0-10V. In open-loop mode, the speed is directly controlled by the frequency converter. In closed-loop mode, an analog PID controller is used, and the difference between the setpoint and feedback value is conditioned through an analog channel and sent to the PID controller. Alternatively, a digital PID controller is used, where the difference between the two values ​​is directly sent to the PID controller, and its output is then conditioned through an analog channel. The input to the speed control circuit is Z, which is 0-10V, and the motor speed is N, which is 0-Nmax. The conventional mapping relationship is as follows:

[0011] Z / 10 = N / Nmax; (1)

[0012] Let the input of the 12-bit D / A conversion channel be X, where X is 0 to 4095; the output voltage be Z, where Z is 0 to 10V; the linear mapping is: X / 4095 = Z / 10; (2)

[0013] Combining (1) and (2), we obtain the analog channel transfer function:

[0014] X / 4095 = N / Nmax; (3)

[0015] A piecewise linear fitting method is used to correct the linear distortion caused by distortion in the simulation loop.

[0016] Further, in the step of converting the digital signal representing the rotation speed into a 0-5V analog signal by the D / A chip, and then conditioning it to 0-10V, DQ11-DQ0 are the data input terminals of the DAC, SEC0 is the selection terminal, directly grounded on a single channel, / WR is the write terminal, the operating voltage of U0 is 5V, limiting the maximum value of OUT1 to 5V, and conditioning it through negative feedback of U3A; when the data input terminal is 4095, the full-bias output of OUT1 is 5V, and when the data input terminal is 0, OUT1 is 0V; through the zero-point correction, amplification and polarity adjustment of the op-amp U3B, the full-bias output is adjusted to close to 12V, U4A is a follower, which acts as a buffer and maintains the signal amplitude unchanged, G1 is an emitter follower, which increases the driving capability, and then conditioning it through resistor R4 to output a 10V voltage;

[0017] The calibration steps include:

[0018] With the data input at 0, adjust potentiometer R0 to make the output of U3B 0V;

[0019] When the input data is 4095, adjust the variable resistor R3 so that the output of U3B is 12V;

[0020] When the data input is 2047, fine-tune the variable resistor R3 to make the output of U3B close to 6V.

[0021] Fine-tune R3 and R4 so that the output of OUT-1 is about 5V. Adjust the variable resistor R4 so that the full-scale bias voltage of OUT-1 is 10V.

[0022] Fine-tune R0 so that when the input is 0, the output of OUT-1 is 0v;

[0023] Repeat the above process until the error at the +10V and 0V points is kept at its optimal level.

[0024] Furthermore, a piecewise linear fitting method is used to correct the linear distortion caused by distortion in the simulation loop, including:

[0025] Define the set of factors of the maximum rotational speed Nmax as A, and s as an element of this set. Then s must divide Nmax evenly. On the coordinate axis, the speed is defined as the X-axis and the value is set as the Y-axis.

[0026] If the interval is s, y = f(x) is an index function, and it is monotonically increasing, then the piecewise linear fitting algorithm is as follows:

[0027] For rotational speed N, let p = N mod s, q = N%s, then f(p) and f(p+1) are the values ​​of the endpoints of the y-axis on the broken line, and m is the offset, which can be obtained from equation (4);

[0028] m / q = [f(p+1)-f(p)] / s;

[0029] m = [f(p+1)-f(p)] / s*q; (4)

[0030] The speed setting is:

[0031] M=f(p)+m=f(p)+[f(p+1)-f(p)] / s*q; (5)

[0032] Relation (5) is the calculation formula for broken line correction, and relation (3) is used to calculate the initial value of the endpoint.

[0033] Furthermore, an 8-digit star-shaped digital tube is used to form the display interface for human-computer interaction, with the first 3 digits being the status bar and the last 5 digits being the information bar.

[0034] When the device is powered on, parameters are imported and the setting state is entered. The corresponding speed can be viewed. When setting the acceleration, each press of ">" increments the item by 1. If the key is not released, it increments by 1 every 500ms. If it is pressed more than 10 times, it increments by 10, and so on, until the key is released, ending the acceleration state. This 10-fold increment accumulation method can be extended to the highest digit. The "<" key is for reverse adjustment. It is stipulated that these two adjustment keys are only used to activate the cursor the first time, without any data increase or decrease operation. If no key is pressed within 10 seconds, the flashing will stop, and the input content will be temporarily stored in the DS12887 RAM.

[0035] Further, press Cor+ or Cor- to enter the calibration state. The interface displays the set speed. Each time Cor+ is pressed, the information bar increases by one 's'. Press Cor- to adjust in the opposite direction. Press Cut to view the corresponding acceleration. Press ">" or "<" to start the inverter and motor. The initial setting value is determined by the index table. Observe the tachometer to perform "table calibration". Press ">" and "<" to make fine adjustments to the setting. The adjustment only affects the output and does not affect the setting. The motor speed changes. The adjustment amount is determined by the adjustment coefficient k. If the adjustment result is satisfactory, press Stop to end. This setting is automatically saved to the index table. The motor stops and enters the setting state. The correction of one end of the broken line is completed.

[0036] Furthermore, pressing the Run button will display the real-time acceleration, allowing you to view the corresponding speed, and will also transfer the system parameters changed by the DS12887 to the 9376B.

[0037] Furthermore, the machine's running date and time parameters are not visible and can only be obtained or set during remote control; pressing the Cut button will temporarily switch to the window specified in the above description, returning after 5 seconds; calibration has a remote lock, which can be used after release; the spacing s value is set remotely; the remote desktop has a password lock, which can only be unlocked by the device administrator.

[0038] Furthermore, the method also includes:

[0039] The first relay controls the start and stop of the frequency converter. When the relay is de-energized, the normally closed (NC) contact closes, shorting 24V to the run / stop terminal of the frequency converter to achieve the stop operation. When the relay is energized, the normally open (NO) contact closes, simulating ground Agnd connected to the run / stop terminal by the (NO) contact, causing the frequency converter to start running. The second relay controls the vacuum valve. Two open collector signals OC1 and OC drive transistors G1 and G2, controlling the 12V relay coil voltage to activate the relay.

[0040] This invention offers the following advantages: A centrifuge linear distortion correction method based on WIA-FA wireless communication is provided. In the centrifuge equipment design, a frequency converter for speed regulation and a Hall sensor for speed measurement are used, employing a PID control method to form a closed-loop control. Through further algorithm optimization, the influence of linear distortion in the control link on the system is eliminated, resolving the troublesome problem of deviation between setpoint and actual values. By implementing a piecewise linear fitting method, the analog loop is corrected, effectively improving control accuracy and operational performance. During measurement, analog calibration is replaced with digital calibration, simplifying operation. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a flowchart of the centrifuge linear distortion correction method based on WIA-FA wireless communication according to the present invention;

[0043] Figure 2 This is the DAC channel circuit diagram;

[0044] Figure 3 This is a schematic diagram of a closed-loop control method;

[0045] Figure 4 It is a linear correction diagram;

[0046] Figure 5 This is a schematic diagram of the system state machine;

[0047] Figure 6 This is a circuit diagram for relay control signals. Detailed Implementation

[0048] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be pointed out that the following detailed description is illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0049] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0050] Exemplary embodiments according to this application will now be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. It should be understood that these embodiments are provided so that the disclosure of this application is thorough and complete, and that the concept of these exemplary embodiments is fully conveyed to those skilled in the art. In the drawings, for clarity, the thickness of layers and regions has been enlarged, and the same reference numerals are used to denote the same devices, and therefore their description will be omitted.

[0051] Please see Figure 1 This invention provides a method for correcting linear distortion in centrifuges based on WIA-FA wireless communication, comprising:

[0052] S101, acquire pulse signals, wherein three magnetic bodies are evenly distributed at a 120-degree angle on the motor rotor of the centrifuge, and Hall effect switches with magnetic sensitivity devices are used for sensing, and three pulse signals are generated for each revolution of the motor.

[0053] Because Hall effect sensors use a non-contact method, dust and electromagnetic interference can affect signal quality. The system uses speed as the target for control, but the standard uses acceleration. The conversion relationship is: w = 2 * 3.14159n, a = rw²; where n is the motor speed, r is the radius of the device from the axis, w is the angular velocity, and a is the acceleration. In this embodiment, r = 355 / 2 mm, g = 9.8 m / s², a is a maximum of 30000 g, and the maximum speed n is determinable, approximately 12300 r / min. For ease of description, this value can be represented by Nmax.

[0054] The centrifuge is equipped with a WIA-FA communication module, which connects the centrifuge to a WIA-FA wireless network for transmitting operating parameters and recording results. WIA-FA technology is a domestically developed and controllable industrial wireless technology standard used in industrial environments, designed for high-speed, hard real-time discrete intelligent manufacturing. It enables highly secure, reliable, and interference-resistant information exchange between automated devices within a factory. By connecting the centrifuge to the WIA-FA wireless network through the WIA-FA communication module, the transmission of operating parameters and recording results ensures data confidentiality and prevents the leakage of classified information.

[0055] S102, the pulse signal is amplified, shaped and filtered to remove glitches and background interference.

[0056] S103 counts the pulse signals within the sampling period and calculates the instantaneous speed of the motor.

[0057] S104 uses a D / A chip to convert the digital signal representing the rotational speed into a 0-5V analog signal, which is then conditioned to 0-10V. In open-loop mode, it directly controls the frequency converter to achieve speed regulation. In closed-loop mode, an analog PID controller is used, and the difference between the setpoint and feedback value is conditioned through an analog channel and sent to the PID controller. Alternatively, a digital PID controller is used, where the difference between the two values ​​is directly sent to the PID controller, and its output is then conditioned through an analog channel. The speed regulation input is Z, which is 0-10V, and the motor speed is N, which is 0-Nmax. The conventional mapping relationship is as follows:

[0058] Z / 10 = N / Nmax; (1)

[0059] Let the input of the 12-bit D / A conversion channel be X, where X is 0 to 4095; the output voltage be Z, where Z is 0 to 10V; the linear mapping is: X / 4095 = Z / 10; (2)

[0060] Combining (1) and (2), we obtain the analog channel transfer function:

[0061] X / 4095 = N / Nmax. (3)

[0062] The transmission channel includes: a D / A converter, voltage conditioning circuit, PID control, frequency converter, etc., with closed-loop operation as follows: Figure 3 As shown.

[0063] Specifically, please refer to Figure 2 DQ11 to DQ0 are the data input terminals of the DAC, SEC0 is the selection terminal, directly grounded for a single channel, / WR is the write terminal, the operating voltage of U0 is 5V, limiting the maximum value of OUT1 to 5V, and the output signal is more stable through negative feedback conditioning by U3A; when the data input terminal is 4095, the full-bias output of OUT1 is 5V, and when the data input terminal is 0, OUT1 is 0V; through the zero-point correction, amplification and polarity adjustment of the op-amp U3B, the full-bias output is adjusted to close to 12V; U4A is a follower, which acts as a buffer and maintains the signal amplitude; G1 is an emitter follower, which increases the driving capability; and the output voltage is 10V after conditioning by resistor R4.

[0064] The calibration steps include: when the data input is 0, adjust potentiometer R0 to make the output of U3B 0V; when the input data is 4095, adjust variable resistor R3 to make the output of U3B 12V; when the data input is 2047, fine-tune variable resistor R3 to make the output of U3B close to 6V; fine-tune R3 and R4 to make the output of OUT-1 approximately 5V; adjust variable resistor R4 to make the full-scale bias voltage of OUT-1 10V; fine-tune R0 so that when the input is 0, the output of OUT-1 is 0V; repeat the above process until the error at +10V and 0V is kept optimal, and the errors at intermediate and other points need to be corrected in the calibration process.

[0065] The process and standards require the equipment to achieve an acceleration of 30,000g (g = 9.8m / s²), with commonly used values ​​being 5,000g, 10,000g, 20,000g, and 30,000g. Therefore, the real-time speed display and setting process can be converted into acceleration form to facilitate human-machine interaction. During measurement and calibration, it can be presented in speed form, and ultimately, the speed quantity is used for description and application in control.

[0066] Although theoretically the setting, feedback, and PID control, including the motor itself, are linear transmission relationships, in reality there will be distortions, such as... Figure 4 The diagrams A and B illustrate this. Therefore, this invention focuses on the relationship between motor speed and set value.

[0067] S105 uses a piecewise linear fitting method to correct the linear distortion caused by distortion in the simulation loop.

[0068] Using a 12-bit D / A converter allows for very precise speed control. However, distortions in the D / A setting channel, feedback channel, and PID speed control circuitry can all introduce linear distortion, causing the speed at certain points to deviate significantly from the actual value. If this is not corrected, firstly, relevant standards cannot be effectively implemented, and secondly, the process parameters and effects cannot be fully reproduced on other equipment, causing unnecessary problems. In conclusion, relying on potentiometer adjustments to "calibrate" the meter is sometimes ineffective and may even fail metrological audits. Therefore, nonlinear adjustments are essential.

[0069] In fact, regardless of whether the distortion occurs in the speed regulation or setting stage, as long as the overall transfer function Y = F(X) is monotonically increasing, that is, for any X [0 ≤ X ≤ 4095], there is a unique Y [0 ~ Nmax] corresponding to it one-to-one, and when X0 ≤ X1, F(X0) ≤ F(X1), showing comparability. The inverse function also has the same characteristic. This mathematical expression represents the necessary performance state for linear devices or linear transfer functions. Due to the existence of distortion, if several discrete points are taken in the Y domain and are uniformly distributed, the corresponding point set in the X domain will be nonlinearly distributed. Therefore, given Y, X cannot be obtained linearly through calculation; a lookup table is needed for indexing.

[0070] In fact, because the function Y = F(X) is unknown, such as Figure 4 The goal is to control the motor speed, and then work backward to deduce the corresponding set input value. This value needs to be obtained through measurement. Once this correspondence is determined, the X data can be indexed by Y. This data structure is a linear list or a one-dimensional array. The process of forming this numerical correspondence when the output Y determines the input X is called nonlinear correction, which can also be considered as a metrological calibration process.

[0071] In general, it is impractical to perform full fine-tuning. A piecewise linear fitting method can be used, which involves calibrating only at a few points and using linear interpolation between adjacent points. This method can also fit the actual curve well, ensuring accuracy while making the calibration process simpler and more convenient.

[0072] In this embodiment, a piecewise linear fitting method is used to correct the linear distortion caused by distortion in the simulation loop, including:

[0073] Define the set of factors of the maximum rotational speed Nmax as A, and s as an element of this set. Then s must divide Nmax evenly. On the coordinate axis, the speed is defined as the X-axis and the value is set as the Y-axis.

[0074] If the interval is s, y = f(x) is an index function, and it is monotonically increasing, then the piecewise linear fitting algorithm is as follows:

[0075] For rotational speed N, let p = N mod s, q = N%s, then f(p) and f(p+1) are the values ​​of the endpoints of the y-axis on the broken line, and m is the offset, which can be obtained from equation (4);

[0076] m / q = [f(p+1)-f(p)] / s;

[0077] m = [f(p+1)-f(p)] / s*q; (4)

[0078] The speed setting is:

[0079] M=f(p)+m=f(p)+[f(p+1)-f(p)] / s*q; (5)

[0080] When p is the top, f(p+1) is meaningless. At this moment, due to the constraint of s, q must be 0, that is, M = f(p), and the formula still holds. Relation (5) is the calculation formula for broken line correction, and relation (3) is used to calculate the initial value of the endpoint. And form an uncorrected index table. Why initialize this table? Because the result of linear mapping may be closer to the desired setting value than random numbers, which is convenient for adjustment. At this moment, calculating the setting value using equation (5) is equivalent to calculating the setting value using equation (3), because the current index table is still in the linear stage. Therefore, after correction, the result calculated using equation (5) is closer to reality.

[0081] According to equation (5), by selecting the speed interval s, p is determined. When the speed N < s, p = 0. Let N = Nmax, and the corresponding p is Ptop. The maximum storage space is 0 to Ptop. Generally, Ptop < 1k is sufficient. In this embodiment, Nmax > 10000 r / min, and the mapping space is selected as 0 to 4095, so the resolution is compressed. Why isn't a larger space selected? Because this means that a D / A converter with a higher bit width also needs to be selected to improve the resolution. At the same time, it also requires that the frequency converter must have this follow-up ability, and the cost is relatively high. In principle, it only needs to meet the metering requirements, and the loss caused by compression can be ignored. Moreover, this does not affect the description and discussion of a method, idea, and example application at all. For the control method with the motor speed as the target, the corresponding set value is deduced by speed, and the control result is accurate.

[0082] If calculated by equation (4), when N = 50, the calculated value is X0, then X0 / 10*K (K is a positive integer) can be used as the calibration variable. The larger K is, the larger the adjustment amount. It can be seen that the minimum calibration step is 5 r / min. Define K (1 ≤ K ≤ 99) as the calibration coefficient.

[0083] Furthermore, the present invention uses an 8-bit cross-shaped digital tube to form a display interface for human-machine interaction. The first 3 bits are the status bar, and the last 5 bits are the information bar.

[0084] When the device is powered on, parameters are imported and it enters the setting state. The corresponding speed can be switched and viewed. When setting the acceleration, each time the ">" key is pressed, this item increases by 1. If the key is not lifted, it continuously increases by 1 every 500 ms. If it continuously exceeds 10 times, it becomes an increase of 10,... until the key is lifted, ending the acceleration state. This 10-fold incremental accumulation method can extend to the highest bit; the "<" key is for reverse adjustment. It is stipulated that these two adjustment keys are only used to activate the cursor for the first time, and there is no data increase or decrease operation. If no key is pressed within 10 s, the flashing stops, and the input content is stored in the DS12887 ram for temporary storage.

[0085] Press Cor+ or Cor- to enter the calibration state. The set speed is displayed on the interface. Each time Cor+ is pressed, the information bar increases by one s amount. Pressing Cor- has the opposite adjustment direction. Press Cut to view the corresponding acceleration. Press ">" or "<", and the frequency converter and the motor start. The initial set value is determined by the index table. Observe the tachometer to "align the watch". Press ">" and "<" to finely adjust the increase and decrease of the set value. The adjustment only affects the output and does not affect the setting. When the motor speed changes, the adjustment amount is determined by the calibration coefficient k. If the adjustment result is satisfactory, press Stop to end, and this set value is automatically saved to the index table. The motor stops and enters the setting state, completing the correction of one end point of the broken line.

[0086] Press the Run button to operate the system, displaying the real-time acceleration. You can switch to view the corresponding speed and save the system parameters changed by DS12887 to 9376B. During control operation, changing the set value is a major disturbance factor. Frequent changes to this value will subject the inverter and motor to huge shocks, causing damage to the machine. In this case, only the Stop button will work.

[0087] The machine's running date, time, and other parameters are not visible and can only be obtained or set during remote control. The Cut button will temporarily switch to the window specified in the above description and return after 5 seconds. Calibration has a remote lock, which can be used after release. The spacing s value is set in the remote control. The remote desktop has a password lock, which can only be unlocked by the device administrator. Changing the spacing value must be done with great care. For example, if the calibration button is pressed, when the new and old spacings are multiples of each other, the overlapping points will be reset to the new index table, and the non-overlapping points will be updated in a linear manner according to formula (4), causing damage to the index table. The above remote control is based on the WIA-FA wireless network.

[0088] Calibration doesn't need to be completed all at once. If 's' is selected very small, there will be many points to be calibrated. First, calibrate the points near the working point, then you can turn on the machine. In this application example, it is recommended to set 's' to 500 r / min and the number of calibration points to be between 200 and 300. Overheating, excessive evacuation time, and excessive noise will trigger alarms, which should be addressed promptly. The buzzer is driven by different square waves from the DS12887; press any key to deactivate it. Please refer to the state transition relationship. Figure 5 System state machine.

[0089] Figure 6 For the relay control logic of the frequency converter, this example only controls the run / stop function. The signal is a switching quantity. Some signals can be fixed, such as the forward / reverse control terminal, which is fixed to forward rotation. The reset function is not selected. The frequency converter combines the run and stop functions into one terminal. Grounding is the running state, and high connection or floating is the stop state. Therefore, a set of relays (including normally open and normally closed contacts) is used to implement the control.

[0090] The first relay controls the start and stop of the frequency converter. When the relay is de-energized, the normally closed (NC) contact closes, shorting 24V to the run / stop terminal of the frequency converter to achieve the stop operation. When the relay is energized, the normally open (NO) contact closes, simulating ground Agnd connected to the run / stop terminal by the (NO) contact, causing the frequency converter to start running. The second relay controls the vacuum valve. Two open collector signals OC1 and OC drive transistors G1 and G2, controlling the 12V relay coil voltage to activate the relay.

[0091] In summary, centrifuges are mainly used in research institutes and machinery factories for acceleration testing, providing support and assurance for related research and product inspection. This invention, through nonlinear correction of the analog channel, reduces the motor speed error from ±5% using traditional methods to ±2%, achieving a more ideal control effect and making speed adjustment smoother and more refined. This method allows the accuracy of each operating point to be adjusted to an ideal state, eliminating the mutual coupling and interference issues inherent in traditional potentiometric calibration, improving measurement efficiency, and enhancing equipment and inspection quality. This method has also shown good results in open-loop motor control. The piecewise linear correction method is not only suitable for speed correction but also for the correction of engineering quantities such as temperature, flow rate, and pressure, and has broad application prospects.

[0092] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0093] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented, for example, in sequences other than those illustrated or described herein.

[0094] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for correcting linear distortion in centrifuges based on WIA-FA wireless communication, characterized in that, include: The centrifuge acquires pulse signals by using three magnetic bodies evenly distributed at a 120-degree angle on the motor rotor. A Hall effect switch with magnetic sensitivity is used for sensing, and three pulse signals are generated for each revolution of the motor. The centrifuge has a WIA-FA communication module, which is used to connect the centrifuge to the WIA-FA wireless network and transmit working parameters and result records through the WIA-FA wireless network. The pulse signal is amplified, shaped, and filtered to remove glitches and background interference. The instantaneous speed of the motor is obtained by counting the pulse signals within the sampling period and converting them. The digital signal representing the rotational speed is converted into a 0-5V analog signal by a D / A chip, and then conditioned to 0-10V. In open-loop mode, the speed is directly controlled by the frequency converter. In closed-loop mode, an analog PID controller is used, and the difference between the setpoint and feedback value is conditioned through an analog channel and sent to the PID controller. Alternatively, a digital PID controller is used, where the difference between the two values ​​is directly sent to the PID controller, and its output is then conditioned through an analog channel. The input to the speed control circuit is Z, which is 0-10V, and the motor speed is N, which is 0-Nmax. The conventional mapping relationship is as follows: Z / 10 = N / Nmax; (1) Let the input of the 12-bit D / A conversion channel be X, where X is 0 to 4095; the output voltage be Z, where Z is 0 to 10V; the linear mapping is: X / 4095 = Z / 10; (2) Combining (1) and (2), we obtain the analog channel transfer function: X / 4095 = N / Nmax; (3) A piecewise linear fitting method is used to correct the linear distortion caused by distortion in the simulation loop.

2. The centrifuge linear distortion correction method based on WIA-FA wireless communication as described in claim 1, characterized in that, In the process of converting the digital signal representing the rotation speed into a 0-5V analog signal by the D / A chip, and then conditioning it to 0-10V, DQ11-DQ0 are the data input terminals of the DAC, SEC0 is the selection terminal, directly grounded for a single channel, / WR is the write terminal, U0 operates at 5V, limiting the maximum value of OUT1 to 5V, and is conditioned by negative feedback from U3A; when the data input terminal is 4095, the full-bias output of OUT1 is 5V, and when the data input terminal is 0, OUT1 is 0V; through zero-point correction, amplification, and polarity adjustment by the op-amp U3B, the full-bias output is adjusted to close to 12V; U4A is a follower, which acts as a buffer and maintains the signal amplitude; G1 is an emitter follower, which increases the driving capability; and finally, the output is conditioned to 10V by resistor R4. The calibration steps include: With the data input at 0, adjust potentiometer R0 to make the output of U3B 0V; When the input data is 4095, adjust the variable resistor R3 so that the output of U3B is 12V; When the data input is 2047, fine-tune the variable resistor R3 to make the output of U3B close to 6V. Fine-tune R3 and R4 so that the output of OUT-1 is about 5V. Adjust the variable resistor R4 so that the full-scale bias voltage of OUT-1 is 10V. Fine-tune R0 so that when the input is 0, the output of OUT-1 is 0v; Repeat the above process until the error at the +10V and 0V points is kept at its optimal level.

3. The centrifuge linear distortion correction method based on WIA-FA wireless communication as described in claim 1, characterized in that, A piecewise linear fitting method is used to correct the linear distortion caused by distortion in the simulation loop, including: Define the set of factors of the maximum rotational speed Nmax as A, and s as an element of this set. Then s must divide Nmax evenly and share it equally. On the coordinate axis, the speed is defined as the X-axis and the value is set as the Y-axis. If the interval is s, y = f(x) is an index function, and it is monotonically increasing, then the piecewise linear fitting algorithm is as follows: For rotational speed N, let p = N mod s, q = N%s, then f(p) and f(p+1) are the endpoint values ​​of the y-axis on the broken line, and m is the offset, which can be obtained from equation (4); m / q = [f(p+1)-f(p)] / s; m = [f(p+1)-f(p)] / s*q; (4) The speed setting is: M=f(p)+m=f(p)+[f(p+1)-f(p)] / s*q; (5) Relation (5) is the calculation formula for broken line correction, and relation (3) is used to calculate the initial value of the endpoint.

4. The centrifuge linear distortion correction method based on WIA-FA wireless communication as described in claim 1, characterized in that, The display interface is composed of 8-digit star-shaped digital tubes for human-computer interaction. The first 3 digits are the status bar and the last 5 digits are the information bar. When the device is powered on, parameters are imported and the setting state is entered. The corresponding speed can be viewed. When setting the acceleration, the item increases by 1 each time the ">" key is pressed. If the key is not released, it will continuously increase by 1 every 500ms. If it is pressed more than 10 times, it will increase by 10, and so on, until the key is released, ending the acceleration state. This 10-fold increment accumulation method can be extended to the highest digit. The "<" key is for reverse adjustment. It is stipulated that these two adjustment keys are only used to activate the cursor the first time, and there is no data increase or decrease operation. If no key is entered within 10 seconds, the flashing will stop, and the input content will be temporarily stored in the DS12887 RAM.

5. The centrifuge linear distortion correction method based on WIA-FA wireless communication as described in claim 4, characterized in that, Press Cor+ or Cor- to enter calibration mode. The interface displays the set speed. Each press of Cor+ increments the information bar by one 's'. Press Cor- to reverse the adjustment direction. Press Cut to view the corresponding acceleration. Press ">" or "<" to start the inverter and motor. The initial setting is determined by the index table. Observe the tachometer to perform "table calibration". Press ">" and "<" to fine-tune the setting. The adjustment only affects the output and does not affect the setting. The motor speed changes. The adjustment amount is determined by the adjustment coefficient k. If the adjustment result is satisfactory, press Stop to end. This setting is automatically saved to the index table. The motor stops and enters the setting mode. The correction of one end of the broken line is completed.

6. The centrifuge linear distortion correction method based on WIA-FA wireless communication as described in claim 5, characterized in that, Press the Run button to run the program, which displays the real-time acceleration. You can switch to view the corresponding speed and save the system parameters changed by DS12887 to 9376B.

7. The centrifuge linear distortion correction method based on WIA-FA wireless communication as described in claim 6, characterized in that, The machine's running date and time parameters are not visible; they can only be obtained or set during remote control. Pressing the Cut button will temporarily switch to the window specified in the above description, returning after 5 seconds. Calibration has a remote lock; it can be used after being released. The spacing s value is set remotely. The remote desktop has a password lock, which can only be unlocked by the device administrator.

8. The centrifuge linear distortion correction method based on WIA-FA wireless communication as described in claim 1, characterized in that, The method further includes: The first relay controls the start and stop of the frequency converter. When the relay is de-energized, the normally closed (NC) contact closes, shorting 24V to the run / stop terminal of the frequency converter to achieve the stop operation. When the relay is energized, the normally open (NO) contact closes, and the analog ground Agnd is connected to the run / stop terminal through the normally open contact (NO), causing the frequency converter to start running. The second relay controls the vacuum valve. Two open collector signals OC1 and OC2 drive transistors G1 and G2, controlling the 12V relay coil voltage to activate the relay.

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