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Mechanical Industry Standard of the People's Republic of China
JB/T5492-91
Potentiometer Pressure Sensor
Published on 1991-07-15
Ministry of Machinery and Electronics Industry
Implementation on 1992-07-01
Mechanical Industry Standard of the People's Republic of China
Potentiometer Pressure Sensor
Subject Content and Scope of Application
JB/T5492--91
This standard specifies the technical requirements, test methods, inspection rules, packaging and storage of potentiometer pressure sensors. This standard applies to linear pressure sensors (hereinafter referred to as sensors) whose conversion elements are potentiometers (including wirewound potentiometers, conductive plastic potentiometers, metal film potentiometers and synthetic film potentiometers). This sensor is suitable for measuring the pressure of gas and liquid media. Reference standards
GB4439
GB4451
ZBY002
ZBY003
3 Measurement range
Priority number and priority number system
Working conditions of industrial automation instruments - vibration Industrial automation instruments Vibration (sinusoidal) test method Instrument transportation, transportation and storage Basic environmental conditions and test methods Instrument packaging technical conditions
The measurement range of the sensor should comply with the following series regulations: 0~0.16, 0~0.25; 0~0.4; 0~0.60~1, 0~1.6, 0~2.5; 0~4; 0~6, 0~100~16; 0~25; 0~40; 0~60MPa.
Note: The measurement range beyond the series listed above can be expanded according to the R5 series. Technical requirements
4.1 Reference working conditions
The reference working conditions of the sensor are:
a. Ambient temperature: 20±5℃;
b. Relative humidity: 45%~75%,
c. Atmospheric pressure: 86kPa to 106kPa. 4.2 Normal working conditions
The normal working conditions of the sensor are:
a. Ambient temperature: -40~70℃;
b. Relative humidity: 5%~95%
c. Atmospheric pressure: 86kPa to 106kPa. 4.3 Accuracy grade and basic error limit
The accuracy grade and basic error limit of the sensor shall comply with the provisions of Table 1. Approved by the Ministry of Machinery and Electronics Industry on July 15, 1991 and implemented on July 1, 1992
Accuracy level
Note: The values in brackets are only applicable to existing products. JB/T5492-91
Basic error limit (percentage of range output) ±0.5
The accuracy of the sensor is calculated according to the test data in accordance with the formula (20) of Article 6.4, and its value should not be greater than the basic error limit corresponding to the accuracy level specified in Table 1.
4.4 Total resistance of potentiometer and relative output resistance The total resistance value of the potentiometer in the sensor should meet the design requirements. The lower limit value, upper limit value and relative output resistance of the sensor should meet the requirements of Table 2. The relative output resistance of the sensor is defined as: R13×100%
In the formula: R-—relative output resistance of the sensor, %R13-output resistance of the sensor, 2;
R12—total resistance of the potentiometer in the sensor, 2. Potentiometer of sensor
Schematic diagram of sensor output circuit
Measurement lower limit output relative resistance
4.5 Nonlinearity
JB/T5492-91
Measurement upper limit output relative resistance
Range output relative resistance
≥92%
The working characteristic straight line of the sensor adopts the end point translation straight line, and the nonlinearity of the sensor shall comply with the provisions of nonlinearity in Table 3. Table 3
Accuracy level
4.6 Hysteresis
Nonlinearity
(Percentage of range output)
(≤2)
The hysteresis of the sensor shall comply with the provisions of hysteresis in Table 3. 4.7 Repeatability
The repeatability of the sensor shall comply with the provisions of repeatability in Table 3. 4.8 Friction error
(Percent of range output)
(≤2)
Repeatability
(Percent of range output)
(≤2)
The friction error of the sensor should not be greater than 1/2 of the absolute value of the basic error limit specified in Table 1. The calculation formula for friction error is as follows: f=Au'.
Where: f--friction error of the sensor, %; X100%..
AU.--output change value before and after tapping the same test point, the maximum value of all test points within the measurement range, V, Ups
-range output value of the sensor, V.
4.9 Resolution
For sensors whose conversion element is a wire-wound potentiometer, its resolution should not be greater than 1/2 of the absolute value of the basic error limit specified in Table 1. The calculation formula of resolution is as follows;
Wherein, r is the resolution of the sensor, %
JB/T5492—91
△U\-the maximum step value of the sensor output within the measuring range, V, Ur.s-
4.10 Overload
The range output value of the sensor, V.
The sensor should be able to withstand the pressure value specified in Table 4 for 1 minute. After the pressure is released, the sensor should still meet the requirements of Articles 4.3 to 4.7. Table 4
Upper limit of measurement
4.11 Insulation resistance
The insulation resistance between each terminal of the sensor and the housing shall not be less than 50M9. 4.12 Influence of ambient temperature change
Pressure value
2 times the upper limit of measurement
1.25 times the upper limit of measurement
When the working ambient temperature of the sensor deviates from 20±5℃, the temperature error of the sensor shall comply with the following formula. o,≤k[t,-t]
Where: 8-sensor temperature error, %, (4)
-sensor temperature coefficient, for 0.5, 1, 1.5 level sensors, take 0.4%/10℃, for 2, 2.5, 4 level sensors, take 0.6%/10℃;
t,-the actual value of the reference temperature when determining the working characteristics of the sensor, ℃, t-any value within the normal working ambient temperature range, ℃. 4.13 Effect of humidity and heat
After the sensor is subjected to a humidity and heat test of 91% to 95% relative humidity and 40 ± 2°C for 48 hours, the insulation resistance between each terminal and the housing should be no less than 5M2, and the surface should be free of discoloration and paint peeling. 4.14 Working life
The sensor should be able to withstand the alternating pressure test of the sinusoidal waveform specified in Table 5. After the test, the sensor should still meet the requirements of Articles 4.3 to 4.8.
4.15 Working vibration
Alternating amplitude
(of the measuring range)
JB/T5492-91
30%~70%
Alternating frequency
times/minute
Alternating times
The sensor should be able to withstand the working vibration of VH, 5 level specified in GB4439. After the vibration test, the sensor should still meet the requirements of Articles 4.3 to 4.8.
4.16 Vibration resistance contact continuity
When the sensor vibrates at a frequency of 10Hz, a displacement amplitude of 0.20mm and a frequency of 500Hz, an acceleration amplitude of 30m/s, the output of the sensor should be continuous when the input pressure changes evenly within the measurement range. 4.17 Appearancebzxz.net
The outer surface of the sensor should be free of visible defects, the coating should be uniform, the fasteners should not be loose or damaged, and the joint threads should be free of obvious burrs and damage.
8 Transport environment resistance
The sensor should meet the requirements of ZBY002 when transport packaging is used. Among them: high, low temperature and damp heat items can be exempted, and the free fall height is 250mm. After the test, the sensor should still meet the requirements of Articles 4.3 to 4.8 and 4.17. 5 Test method
5.1 Test requirements
5.1.1 Test sequence and time interval
The test sequence and time interval of the sensor type are shown in Appendix A (reference). 5.1.2 Test conditions
According to the reference working conditions in Article 4.1.
5.1.3 Test points
a. The pressure test points of the sensor should be no less than 6 points (including the zero point), and each test point should be evenly distributed within the measurement range. b. During the test, the input pressure of the same stroke should approach the test point in the same direction. 5.1.4 Measurement cycle
When the sensor is tested for accuracy, nonlinearity, hysteresis and repeatability, three measurement cycles should be carried out continuously. The friction error test can be carried out in one of the measurement cycles. 5.1.5 Output of sensor
During the test, the output of the sensor can be expressed as percentage voltage output or percentage resistance output. The data processing and performance index calculation in Article 6 of this standard are expressed as percentage voltage output. 5.1.6 Output measuring instrument
The accuracy of the instrument measuring the output of the sensor should not be less than 1/5 of the accuracy of the sensor under test within the corresponding range. 5.1.7 Pressure source
JB/T5492--91
The absolute value of the absolute error of the pressure source should not be greater than 1/3 of the absolute value of the absolute error of the sensor under test. 5.1.8 Power supply
The DC voltage stability of the power supply of the sensor under test should not be less than 1/5 of the accuracy of the sensor under test. 5.2 Verification of total resistance and relative output resistance of potentiometer Use a resistance measuring instrument to measure the total resistance of the sensor and the lower limit value, upper limit value and relative resistance of the range output. 5.3 Nonlinearity test
Steady pressure is applied to the sensor from zero, and the pressure is tested from the specified test point to the upper limit of the measurement, and the pressure is then steadily reduced, and each test point is tested to zero. This test is carried out for three consecutive measurement cycles, and the nonlinearity of the sensor is calculated according to the test data according to the formula (5) of Article 6.1.
5.4 Hysteresis test
Based on the data obtained from the nonlinearity test, the hysteresis of the sensor is calculated according to the formula (15) of Article 6.2. 5.5 Repeatability test
Based on the data obtained from the nonlinearity test, the repeatability of the sensor is calculated according to the formula (16) of Article 6.3. 5.6 Accuracy test
Based on the data obtained from the nonlinearity test, the accuracy of the sensor is calculated according to the formula (20) of Article 6.4. 5.7 Friction error test
In a measurement cycle of the nonlinearity test, tap the sensor at each test point, read the output values before and after tapping respectively, select the maximum value and calculate the friction error according to formula (2) of Article 4.8. 5.8 Resolution test
Connect the output end of the sensor to be tested to the X-axis input end of the X-Y recorder, and connect the output end of the sensor with continuous resolution to the Y-axis input end of the X-Y recorder. Use the same pressure source to slowly and evenly pressurize the two sensors from zero to the upper limit of the measurement, record the maximum step voltage output by the sensor within the measurement range, and calculate the resolution according to formula (3) of Article 4.9. 5.9 Overload test
Apply the pressure value specified in Table 4 of Article 4.10 to the sensor and maintain it for 1 minute, then reduce the pressure to zero, stay for 5 minutes, and test according to Articles 5.2 to 5.6.
5.10 Insulation resistance test
Use a megohmmeter or high resistance tester to measure the insulation resistance between each sensor terminal and the housing at a voltage of 100V. 5.11 Test on the influence of environmental temperature change
Put the sensor in a high (low) temperature test chamber, gradually increase (decrease) the temperature to the upper (lower) limit of the temperature specified in Article 4.2, and then apply a pressure of 50% of the upper limit of the measurement to the sensor. After the temperature stabilizes, keep it warm for 2 hours, and then reduce the pressure of the sensor to zero. Steadily increase the pressure of the sensor from zero to the specified test point to the upper limit of the measurement, and keep it for 1 minute. Then steadily reduce the pressure to zero at each test point. Carry out the test for three consecutive measurement cycles. Calculate the temperature error according to formula (22) of Article 6.5 based on the test data. 5.12 Humidity and heat influence test
Put the sensor in a humidity and heat test chamber, set the temperature of the test chamber to 40±2℃ and the relative humidity to 91%~95%, and keep it for 48 hours. Then take the sensor out of the test box, move it to the test conditions of 5.1.2 within 10 minutes, and use a megohmmeter or high resistance tester to complete the insulation resistance measurement between each sensor terminal and the shell at 100V voltage within 30 minutes. At the same time, observe that the surface of the sensor should not be discolored or peeled.
5.13 Working life test
The sensor shall be tested for working life in accordance with Article 4.14, and tested in accordance with Articles 5.2 to 5.7 after the test. 5.14 Working vibration test
The axial schematic diagram of the sensor is shown in Figure 2.
JB/T5492-91
The sensor shall be tested for vibration in accordance with GB4451 (the sensor shall be wired in accordance with Figure 3), and the vibration level shall be 3c. During the test, a pressure of 50% of the upper limit of the measurement value shall be applied to the sensor, and the durability test shall be a fixed frequency test. After the test, it shall be tested in accordance with Articles 5.2 to 5.7. Figure 2
Potentiometer of sensor
Axial schematic diagram of sensor
Oscilloscope
Figure 3 Wiring diagram of sensor working vibration and anti-vibration contact continuity 5.15 Anti-vibration contact continuity test
JB/T5492-91
Install the sensor on the vibration test bench in the X, Y and Z axes respectively, and apply mechanical vibration with a frequency of 10Hz, a displacement amplitude of 0.20mm, a frequency of 500Hz and an acceleration amplitude of 30m/s in each axial direction (if the resonance point of the sensor coincides with these two frequency points, avoid this resonance point and select another point nearby), then make the sensor input change evenly in the upper and lower strokes within the measurement range within a time of not less than 30s, and use an oscilloscope to check the contact continuity of the sensor (the sensor is wired as shown in Figure 3). When the pulse burrs or graph jumps on the oscilloscope are greater than 5% of the power supply voltage, the output is discontinuous. 5.16 Test of resistance to transport environment
The sensor shall be tested in accordance with the provisions of ZBY002, and after the test, it shall be inspected in accordance with Articles 5.2 to 5.7. 5.17 Appearance inspection
Visual inspection.
Data processing and performance indication calculation
In the following calculations, the output values of the sensor are expressed as a percentage of the power supply voltage applied at that time. 6.1 Nonlinearity
The nonlinearity of the sensor is calculated as follows: St = AUulx × 100%
Wherein: I△Ulx = |,-U;lmx\
U..s - IUh- U....
Wherein: U is the average output value of the upper and lower strokes of the th inspection point, %U, is the output value of the working characteristic line of the th inspection point, %; (5)
I△U: Ix is the maximum value of the absolute value of the difference between the output average value of each inspection point within the measurement range and the output value of the working characteristic line (see Figure 4), %;
U is the output value of the upper limit of the working characteristic line measurement, %; U, is the output value of the lower limit of the working characteristic line measurement, %; Up-s is the range output value of the sensor, %. The working characteristic straight line, that is, the endpoint translation straight line (see Figure 4), is calculated as follows: first calculate the endpoint connection line equation, which is: UPH-URPI+UN-UEP
Uep,=!
Wherein: Uepi——the output value of the endpoint connection line of the ith inspection point, %U,——the average output value of the upper and lower strokes of the measurement lower limit, %——the average output value of the upper and lower strokes of the measurement upper limit, %; P, the measurement lower limit, MPas
P the measurement upper limit, MPas
P,——the input pressure value of the ith inspection point, MPa. Calculate the difference between the average output of the forward and reverse strokes and the corresponding UEP respectively: 8
JB/T5492—91
AUu -U.-Ugpi ..
AUp;=Up;-Ugp
Wherein, U is the average output of the upper stroke at the th inspection point, %Up is the average output of the lower stroke at the th inspection point, %-the difference between the average output of the upper stroke at the th inspection point and the output value of the endpoint connection line, %; AU-
△Up: is the difference between the average output of the lower stroke at the th inspection point and the output value of the endpoint connection line, %; Then, the intercept of the endpoint translation line is calculated as follows: P-UP +I(AU,) 1 -I(U,) .
In the formula: (△U,)—the maximum positive deviation of all the test point differences within the measurement range calculated according to formulas (9) and (10), %; (AU)ax
—the maximum negative deviation of all the test point differences within the measurement range calculated according to formulas (9) and (10), %; the intercept of the end point translation line, %,
The meanings of the other variables are the same as in formula (8). The slope of the end point translation line is calculated as follows: b=-
—the slope of the end point translation line, %;
In the formula, b—
The meanings of the other variables are the same as in formula (8). The equation of the endpoint translation line is:
+(,) 1 - 1() 1+
When the measurement lower limit value P=0, the above equation becomes: Us = U++ CI(AU,) - (AU,) 3+,LP,PH
Wherein, Usi is the output value of the endpoint translation line of the j-th inspection point, %. When calculating, U, in (6) is replaced by Usei, (AU) and (AU,）has the same meaning as in (11); the other variables have the same meaning as in (8). (12)
(14）
6.2 Hysteresis H
Output reading
Average calibration curve
(Aun,)
The hysteresis of the sensor is calculated as follows:
JB/T5492—91
Calibration curve
(aun)）
End point translation straight line
(Working characteristic straight line)
End point connection line
Measurement lower limit output value
Figure 4 Schematic diagram of sensor calibration curve
E = AUmlm- ×100%
Where: 1△Ul.ax
Range output value
Input pressure
The maximum absolute value of the difference between the average output value of the upper stroke and the average output value of the lower stroke of all test points within the measuring range (see Figure 4), %
Ur.s——Calculated according to formula (7), %.
6.3 Repeatability s
The repeatability of the sensor is calculated according to the following formula;
Where: SThe standard deviation of the sub-sample of the sensor, %Uls—Calculated according to formula (7), %.
-×100%
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