CN110672187A - Sensor symmetry detection method and device - Google Patents
Sensor symmetry detection method and device Download PDFInfo
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- CN110672187A CN110672187A CN201911070788.2A CN201911070788A CN110672187A CN 110672187 A CN110672187 A CN 110672187A CN 201911070788 A CN201911070788 A CN 201911070788A CN 110672187 A CN110672187 A CN 110672187A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F25/00—Testing or calibration of apparatus for measuring volume, volume flow or liquid level or for metering by volume
Abstract
The invention provides a sensor symmetry detection method and a sensor symmetry detection device, wherein the method comprises the following steps: sequentially applying different first voltage values and second voltage values to two ends of a high-order winding of the sensor; obtaining an output voltage value based on a resistance value change of the high-order winding generated when the first voltage value is switched to the second voltage value; and calculating to obtain a value representing the symmetry of the high-order winding according to the output voltage value. The technical scheme of the sensor symmetry detection method and the sensor symmetry detection device provided by the invention can improve the test efficiency, realize batch detection, and avoid damage to welding points of the sensor and bonding pads of the circuit board and damage to the cleanliness of the circuit board.
Description
Technical Field
The invention relates to the technical field of sensor detection, in particular to a method and a device for detecting symmetry of a sensor.
Background
The gas mass flow controller as a precision measuring instrument plays an important role in a plurality of fields such as the semiconductor industry, the chemical industry, the environmental protection industry and the like. The gas mass flow sensor is used as a core component in the gas mass flow controller, and the performance of the gas mass flow sensor directly influences various performance indexes of the gas mass flow controller, such as important index parameters of precision, null shift, linearity, response time and the like. The symmetry of the high order windings of the sensor (two windings located upstream and downstream) is a very important indicator of the gas mass flow sensor, which determines the quality of the gas control by the gas mass flow controller. Therefore, a symmetry test of the gas mass flow sensor is required to determine whether the symmetry requirement is met.
The traditional symmetry test is to install a sensor in a gas mass flow controller, connect the gas mass flow controller into a gas path, and then test the symmetry of the sensor by introducing gas into the gas path. However, this method is inefficient in testing and is not suitable for mass detection of sensors. Moreover, the sensor needs to be welded on a circuit board of the gas mass flow controller, and the sensor needs to be detached through welding after the test is finished, so that certain damage and even falling of the welding point of the sensor and the welding pad of the circuit board can be caused, and meanwhile, the cleanliness of the circuit board can be damaged through welding.
Disclosure of Invention
The invention aims to at least solve one of the technical problems in the prior art, and provides a sensor symmetry detection method and a sensor symmetry detection device, which can improve the test efficiency, realize batch detection, and avoid damage to a welding point of a sensor and a bonding pad of a circuit board and damage to the cleanliness of the circuit board.
In order to achieve the above object, the present invention provides a sensor symmetry detection method, including:
sequentially applying different first voltage values and second voltage values to two ends of a high-order winding of the sensor;
obtaining an output voltage value based on a change in resistance of the high secondary winding that occurs when the first voltage value switches to a second voltage value;
and calculating a value representing the symmetry of the high secondary winding according to the output voltage value.
Optionally, the first voltage value and the second voltage value are two voltage values generated across the high-order winding before and after the fluid flows through the fluid pipeline of the sensor.
Optionally, the first voltage value is 6V; the second voltage value is 14V.
Optionally, before the step of applying the first voltage value and the second voltage value to the two ends of the high-order winding of the sensor in sequence, the method further includes:
forming a Wheatstone bridge circuit by the high-order winding, two preset resistors and a variable resistor;
in the step of obtaining an output voltage value based on a change in resistance value of the high secondary winding that occurs when the first voltage value is switched to a second voltage value,
and outputting a corresponding voltage value when the first voltage value or the second voltage value is applied by utilizing the Wheatstone bridge circuit.
Optionally, the step of sequentially applying different first voltage values and second voltage values to two ends of the high-order winding of the sensor further includes:
applying the first voltage value across the high order winding;
adjusting the resistance value of the variable resistor to enable a fourth voltage value output by the Wheatstone bridge circuit to be 0V;
and switching the first voltage value to a second voltage value.
Optionally, after the step of adjusting the resistance value of the variable resistor to make the fourth voltage value output by the wheatstone bridge circuit be 0V, the method further includes:
and converting the fourth voltage value into a reading zero, and displaying.
Optionally, after the step of obtaining a value representing symmetry of the high secondary winding according to the output voltage value, the method further includes:
and displaying the numerical value.
The present invention also provides a sensor symmetry detection apparatus, comprising:
the voltage supply unit is used for sequentially applying different first voltage values and second voltage values to two ends of a high-order winding of the sensor;
a voltage output unit for obtaining an output voltage value based on a resistance value change of the high secondary winding generated when the first voltage value is switched to a second voltage value;
and the calculating unit is used for calculating and obtaining a numerical value representing the symmetry of the high secondary winding according to the output voltage value.
Optionally, the voltage providing unit includes:
the first power supply control circuit is used for reducing the 220V alternating voltage to a first alternating voltage value;
the second power supply control circuit is electrically connected with the first power supply control circuit and used for converting the first alternating current voltage value into a reference voltage value;
and the voltage switching circuit is used for selectively switching the reference voltage value to the first voltage value or the second voltage value and applying the reference voltage value to two ends of the high-order winding.
Optionally, the voltage output unit includes two preset resistors and a variable resistor, and forms a wheatstone bridge circuit with the high-order winding.
Optionally, the system further comprises a display unit, configured to display the numerical value obtained by the calculation unit.
Optionally, the system further comprises a digital panel table, and the computing unit and the display unit are integrated in the digital panel table.
Optionally, the first power supply control circuit is further configured to step down the 220V ac voltage to a second ac voltage value;
the voltage supply unit further comprises a third power supply control circuit which is electrically connected with the first power supply control circuit and used for converting the second alternating current voltage value into a direct current voltage value and outputting the direct current voltage value to the digital panel meter.
The invention has the beneficial effects that:
according to the technical scheme of the sensor symmetry detection method and device, different first voltage values and second voltage values are applied to the two ends of the high-order winding of the sensor in sequence, so that when the first voltage value is switched to the second voltage value, resistance value changes generated by the high-order winding before and after gas flows through a pipeline of the sensor can be simulated, and the purpose of testing the symmetry of the high-order winding is achieved. Because can direct test sensor, and need not install the sensor in gas mass flow controller, this not only can improve efficiency of software testing, realizes detecting in batches, can avoid causing the welding point of sensor and the pad damage of circuit board moreover to the destruction to the cleanliness of circuit board.
Drawings
Fig. 1 is a block flow diagram of a sensor symmetry detection method according to a first embodiment of the present invention;
fig. 2 is a block flow diagram of a sensor symmetry detection method according to a second embodiment of the present invention;
fig. 3 is a schematic block diagram of a sensor symmetry detection apparatus according to a third embodiment of the present invention;
fig. 4 is a schematic block diagram of a sensor symmetry detection apparatus according to a fourth embodiment of the present invention;
FIG. 5 is a circuit diagram of a voltage converting circuit according to a fourth embodiment of the present invention;
fig. 6 is a circuit diagram of a wheatstone bridge circuit employed in a fourth embodiment of the present invention.
Detailed Description
In order to make those skilled in the art better understand the technical solution of the present invention, the sensor symmetry detection method and apparatus provided by the present invention are described in detail below with reference to the accompanying drawings.
First embodiment
Referring to fig. 1, the sensor symmetry detection method provided in this embodiment can be applied to the symmetry test of the high-order winding of the mass flow sensor. The high-order winding is two windings respectively positioned at the upstream and the downstream, and the two windings are thermistor wires and have the characteristics of thermistors. When the voltage at the two ends of the two windings changes, the two windings generate heat, and the resistance values of the two windings change according to the characteristics of the thermistor. The symmetry detection method of the sensor provided by the embodiment is based on the principle to realize symmetry test.
Specifically, the method for detecting symmetry of a sensor provided by this embodiment includes the following steps:
and S1, applying different first voltage value and second voltage value to two ends of the high-order winding of the sensor in sequence.
S2, an output voltage value is obtained based on the resistance value change of the high-order winding generated when the first voltage value is switched to the second voltage value.
And S3, calculating and obtaining a value representing the symmetry of the high-order winding according to the output voltage value.
The traditional symmetry test is to install a sensor in a gas mass flow controller, connect the gas mass flow controller into a gas path, and then test the symmetry of the sensor by introducing gas into the gas path. When the sensor during operation, have invariable electric current to flow through high order winding, high order winding can heat up because of producing the heat this moment, when gas passes through the fluid pipeline of gas path inflow sensor, can bring high order winding's part heat to secondary winding, and high order winding's heat change can arouse high order winding's resistance value change simultaneously. Based on this, according to the method for detecting symmetry of a sensor provided by this embodiment, by successively applying different first voltage values and second voltage values to the two ends of the high-order winding of the sensor, when the first voltage value is switched to the second voltage value, the resistance value change generated by the high-order winding before and after the gas flows through the fluid pipeline of the sensor can be simulated, so as to achieve the purpose of testing the symmetry of the high-order winding. That is to say, through making the voltage change at secondary winding both ends replace the mode of letting in gas, direct test sensor no longer need install the sensor in gas mass flow controller, and this not only can improve efficiency of software testing, realizes detecting in batches, can avoid causing the welding point of sensor and the pad damage of circuit board moreover to the destruction to the cleanliness of circuit board.
Optionally, the first voltage value and the second voltage value are two voltage values generated at two ends of the high-order winding before and after the fluid flows through the fluid pipeline of the sensor respectively. Therefore, resistance value changes generated by high-order windings before and after gas flows through a fluid pipeline of the sensor can be simulated. For example, the first voltage value is 6V; the second voltage value is 14V.
Second embodiment
Referring to fig. 2, the method for detecting symmetry of a sensor according to the present embodiment includes the following steps:
and S101, forming a Wheatstone bridge circuit by the high-order winding, two preset resistors and one variable resistor.
And S102, applying different first voltage values and second voltage values to two ends of the high-order winding in sequence.
And S103, outputting a corresponding voltage value when the first voltage value or the second voltage value is applied by using a Wheatstone bridge circuit.
And S104, calculating and obtaining a numerical value representing the symmetry of the high-order winding according to the output voltage value.
The output voltage of the Wheatstone bridge circuit can change along with the voltage change at two ends of the high-order winding, so that the Wheatstone bridge circuit can convert the resistance value change of the high-order winding into the voltage change, and then can calculate and obtain a numerical value representing the symmetry of the high-order winding according to the voltage change, namely, the aim of testing the symmetry of the high-order winding is achieved.
It is easy to understand that the voltage value output by the wheatstone bridge circuit when the first voltage value is switched to the second voltage value is the output voltage value in step S104.
Optionally, the step S102 further includes:
s1021, applying a first voltage value to two ends of the high-order winding;
s1022, adjusting the resistance value of the variable resistor to enable the fourth voltage value output by the Wheatstone bridge circuit to be 0V;
s1023, the first voltage value is switched to the second voltage value.
Thus, when the voltage across the high-order winding is the first voltage value, the value of the voltage output by the wheatstone bridge circuit is set to 0V by adjusting the resistance value of the variable resistor, and the zero adjustment of the value indicating the symmetry of the high-order winding can be realized.
Optionally, after step S1022, the method further includes:
and converting the fourth voltage value into a reading zero, and displaying.
In this way, a reading of zero can be displayed to the user when the voltage across the high order winding is at the first applied voltage value.
Third embodiment
Referring to fig. 3, the sensor symmetry detecting apparatus 1 provided in the present embodiment includes a voltage providing unit 11, a voltage output unit 12, and a calculating unit 13. The voltage providing unit 11 is configured to successively apply a first voltage value and a second voltage value to two ends of the high-order winding 21 of the sensor 2; the voltage output unit 12 is configured to obtain an output voltage value based on a resistance value change of the high-order winding 21 that occurs when the first voltage value is switched to the second voltage value; the calculation unit 13 is configured to obtain a value representing the symmetry of the high secondary winding 21 from the output voltage value calculation.
The sensor symmetry detection device 1 provided by this embodiment can simulate the resistance change of gas generated by the front and rear high-order windings of the fluid pipeline of the sensor when the first voltage value is switched to the second voltage value by successively applying the different first voltage value and second voltage value to the two ends of the high-order winding 21 of the sensor 2, so as to achieve the purpose of testing the symmetry of the high-order winding. That is to say, through making the voltage change at secondary winding 21 both ends replace the mode of letting in gas, direct test sensor no longer need install the sensor in gas mass flow controller, and this not only can improve efficiency of software testing, realizes detecting in batches, can avoid causing the welding point of sensor and the pad damage of circuit board moreover to the destruction to the cleanliness of circuit board.
Fourth embodiment
Referring to fig. 4, a sensor symmetry detection apparatus provided in this embodiment is a specific implementation manner of the third embodiment. Specifically, the voltage supply unit 11 includes a first power supply control circuit 111, a second power supply control circuit 112, and a voltage switching circuit 113, wherein the first power supply control circuit 111 is configured to step down the 220V ac voltage to a first ac voltage value. For example, the first ac voltage value is 18V, and the first power supply control circuit 111 supplies ac power having a voltage of 18V (a current of 1.4A) to the second power supply control circuit 112. The second power control circuit 112 is electrically connected to the first power control circuit 111 for converting the first ac voltage value into a reference voltage value. The voltage switching circuit 113 is configured to selectively switch the reference voltage value to the first voltage value or the second voltage value, and apply the reference voltage value to both ends of the high-order winding 21.
In the present embodiment, referring to fig. 5, the voltage switching circuit 113 includes four resistors (R11, R12, R13, R14) for voltage division, and a selection switch S2. The second power supply control circuit 112 converts the first ac voltage value into a reference voltage value U0, and then supplies the reference voltage value U0 to the voltage switching circuit 113. Specifically, the reference voltage value satisfies, for example, the following formula:
U0＝1.25×(1+R12/R11)
the voltage switching circuit 113 has two output terminals for outputting a first voltage value and a second voltage value, respectively. For example, the first voltage value is 6V; the second voltage value is 14V. The selection switch S2 is used to switch between two output terminals to selectively output the first voltage value or the second voltage value. Optionally, the selection switch S2 is a toggle switch or the like.
In the present embodiment, referring to fig. 6, the voltage output unit 12 includes two preset resistors (R15, R16) and a variable resistor (RP3), and forms a wheatstone bridge circuit with the high-order windings (Rx and Rs). Specifically, sensor 2 has three signal leads (A, B, C). Two preset resistors (R15, R16) and a variable resistor (RP3) are connected in series in a circuit, a first end of the circuit is grounded, and a second end of the circuit is used as an input end of the voltage switching circuit 113. The variable resistor (RP3) is located between the two preset resistors (R15, R16), and the two ends of the active end of the variable resistor (RP3) and the outgoing line B of the sensor 2 are the voltage output ends of the Wheatstone bridge circuit, and the output voltage value is U1. Two lead lines (A, C) of the sensor 2 are connected to both ends of the resistor R15 and the resistor R16, respectively. Thus, a Wheatstone bridge circuit is formed.
Optionally, the variable resistor (RP3) is an adjustable potentiometer.
When the toggle switch S2 is turned on with the output terminal outputting 6V, U0 is 6V, and the wheatstone bridge circuit may be zeroed by the variable resistor (RP3) so that the output voltage value U1 is 0V.
When the toggle switch S2 is switched from the output terminal outputting 6V to the output terminal outputting 14V, U0 is 14V, and at this time, in the wheatstone bridge circuit, the resistances of the high-order windings (Rx and Rs) are changed based on the characteristics of the thermistor, so that the output voltage value U1 is changed accordingly. The calculating unit 13 is configured to calculate a value representing the symmetry of the high secondary winding 21 from the output voltage value U1, wherein the value is capable of reflecting whether the symmetry meets the requirement.
Optionally, the sensor symmetry detection apparatus 1 further includes a display unit, configured to display the value obtained by the calculation unit 13, so that the symmetry of the sensor can be intuitively known.
Optionally, the sensor symmetry detection apparatus 1 further includes a digital panel table 4, and the digital panel table 4 integrates the above calculation unit 13 and the display unit. On this basis, optionally, the first power supply control circuit 111 is further configured to step down the 220V ac voltage to a second ac voltage value. The voltage providing unit further includes a third power control circuit 114 electrically connected to the first power control circuit 111 for converting the second ac voltage value into a dc voltage value and outputting the dc voltage value to the digital panel table 4. For example, the second ac voltage value is 8.5V, and the first power supply control circuit 111 supplies ac power having a voltage of 8.5V (a current of 0.35A) to the third power supply control circuit 114. The third power control circuit 114 converts the alternating current into a direct current of 5V and outputs the digital panel table 4 so that it can normally operate.
In summary, in the technical solutions of the sensor symmetry detection method and the sensor symmetry detection device provided in the embodiments of the present invention, by sequentially applying the first voltage value and the second voltage value to the two ends of the high-order winding of the sensor, when the first voltage value is switched to the second voltage value, the resistance change generated by the high-order winding before and after the gas flows through the pipeline of the sensor can be simulated, so as to achieve the purpose of testing the symmetry of the high-order winding. Because can direct test sensor, and need not install the sensor in gas mass flow controller, this not only can improve efficiency of software testing, realizes detecting in batches, can avoid causing the welding point of sensor and the pad damage of circuit board moreover to the destruction to the cleanliness of circuit board.
It will be understood that the above embodiments are merely exemplary embodiments taken to illustrate the principles of the present invention, which is not limited thereto. It will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the spirit and substance of the invention, and these modifications and improvements are also considered to be within the scope of the invention.
Claims (13)
1. A method for detecting sensor symmetry, comprising:
sequentially applying different first voltage values and second voltage values to two ends of a high-order winding of the sensor;
obtaining an output voltage value based on a change in resistance of the high secondary winding that occurs when the first voltage value switches to a second voltage value;
and calculating a value representing the symmetry of the high secondary winding according to the output voltage value.
2. The sensor symmetry detection method of claim 1, wherein the first and second voltage values are two voltage values generated across the high order winding before and after the fluid flows through the fluid line of the sensor, respectively.
3. The sensor symmetry detection method according to claim 2, characterized in that the first voltage value is 6V; the second voltage value is 14V.
4. The method of claim 1, further comprising, prior to the step of applying the first and second different voltage values sequentially across the high order winding of the sensor:
forming a Wheatstone bridge circuit by the high-order winding, two preset resistors and a variable resistor;
in the step of obtaining an output voltage value based on a change in resistance value of the high secondary winding that occurs when the first voltage value is switched to a second voltage value,
and outputting a corresponding voltage value when the first voltage value or the second voltage value is applied by utilizing the Wheatstone bridge circuit.
5. The method of claim 4, wherein the step of applying the first and second voltages to the high-order windings of the sensor sequentially further comprises:
applying the first voltage value across the high order winding;
adjusting the resistance value of the variable resistor to enable a fourth voltage value output by the Wheatstone bridge circuit to be 0V;
and switching the first voltage value to a second voltage value.
6. The sensor symmetry detection method according to claim 5, further comprising, after the step of adjusting the resistance value of the variable resistor to make the fourth voltage value output by the wheatstone bridge circuit be 0V:
and converting the fourth voltage value into a reading zero, and displaying.
7. The sensor symmetry detection method according to claim 4, further comprising, after the step of obtaining a value representing symmetry of the high secondary winding from the output voltage value calculation:
and displaying the numerical value.
8. A sensor symmetry detection apparatus, comprising:
the voltage supply unit is used for sequentially applying different first voltage values and second voltage values to two ends of a high-order winding of the sensor;
a voltage output unit for obtaining an output voltage value based on a resistance value change of the high secondary winding generated when the first voltage value is switched to a second voltage value;
and the calculating unit is used for calculating and obtaining a numerical value representing the symmetry of the high secondary winding according to the output voltage value.
9. The sensor symmetry detection apparatus according to claim 8, wherein the voltage supply unit includes:
the first power supply control circuit is used for reducing the 220V alternating voltage to a first alternating voltage value;
the second power supply control circuit is electrically connected with the first power supply control circuit and used for converting the first alternating current voltage value into a reference voltage value;
and the voltage switching circuit is used for selectively switching the reference voltage value to the first voltage value or the second voltage value and applying the reference voltage value to two ends of the high-order winding.
10. The sensor symmetry detection apparatus of claim 8, wherein the voltage output unit comprises two preset resistors and a variable resistor, and forms a wheatstone bridge circuit with the high-order winding.
11. The sensor symmetry detection apparatus according to claim 8, further comprising a display unit configured to display the numerical value obtained by the calculation unit.
12. The sensor symmetry detection apparatus according to claim 11, further comprising a digital panel table integrating the calculation unit and the display unit.
13. The sensor symmetry detection apparatus of claim 12, wherein the first power control circuit is further configured to step down the 220 vac voltage to a second ac voltage value;
the voltage supply unit further comprises a third power supply control circuit which is electrically connected with the first power supply control circuit and used for converting the second alternating current voltage value into a direct current voltage value and outputting the direct current voltage value to the digital panel meter.
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