Some standard content:
National Standard of the People's Republic of China
Load cell test procedure
UDC 681.2:531
.781 -620.17
GB5604-85
This standard specifies the general test method for tension, compression or tension-compression dual-purpose electrical measuring sensors (hereinafter referred to as simple displacement sensors) for measuring force and weighing.
This standard does not specify the test methods for certain influencing quantities of sensors (such as displacement, electrical disturbance, etc.). 1 Terminology
The terms used in this standard generally comply with GB503-95 "Terminology of Load Sensors". 2 Test conditions
2.1 Standard test conditions
The test must be carried out under the following conditions:
a. Temperature: 20±2C
b. Relative humidity: 70%;
c. Air pressure: 90~106 kPa (680 ~800mmHg) Note:) Of course, when the standard test conditions are not met, it is allowed to conduct the test under the indoor conditions specified in GB5603-85, and the test station should be kept for half a year. ② When the sensor is tested, the change in the indoor temperature per hour shall not exceed 1 degree. This note applies to any place mentioned in the standard test conditions later.
③ When the use conditions are inconsistent with the test conditions, attention should be paid to the deviation of the relevant technical characteristics caused by this, and the test results should be corrected as needed.
2.2 Loading conditions||tt| |2.2.1 Installation
The sensor should be installed to ensure that the axis of the sensor coincides with the load line, so as to minimize the influence of the tilting load and the eccentric load. 2.2.2 Compression
2.2.2.1 When using any loading device, attention must be paid to the quality of the loading contact. The supporting surface of the sensor and the bottom surface of the sensor should be even and free of corrosion, scratches and debris.
2.2.2.2 The sensor should generally be equipped with an upper and lower pressure. 2.2.3 Tensile
The two ends of the sensor should be connected to the Use appropriate connectors: 2.3 Release time
The sensor should be placed under standard test conditions for a long enough time to ensure that the temperature of the actual and standard test parts is high and stable. It is recommended that the sensor be placed for no less than 8h. 2.4 Preheating
Before the test, the sensor and its connected indicating instrument must be preheated with power supply. The preheating time should meet the requirements of the system! After all parts are determined, the test can be carried out: For sensors or test equipment that the manufacturer does not specify the heating time, the power supply should be set to 0.5~1 h. 2.5 Atmospheric pressure
Where changes in atmospheric pressure may significantly affect the output of the sensor, such changes should be noted. National Bureau of Standards 1985-11-25 Issued
1986-1001 Implementation
2.6 Excitation power supply
GB5E04-85
An excitation power supply with sufficient stability and accuracy must be used. Its accuracy index should generally be better than the relevant accuracy index of the tested sensor. The excitation value should be the manufacturer's recommended value. 12.7 Indicating instrument
The accuracy of the indicating instrument used to test the accuracy index of the sensor should be at least 3 times better than the corresponding accuracy index of the sensor. The indicating instrument should be calibrated regularly. The calibration values of the indicating instrument with a calibration mechanism before and after the test must be recorded. The self-calibration mechanism should be regularly compared with instruments with higher accuracy.
3 Force Standard Machine and Loading Device
Force standard machine usually uses the gravity generated by the silicon code with accurate mass in the gravity field with accurate measured gravity acceleration to directly or indirectly (through lever: or through cylinder piston system, etc.) load the sensor. At this time, the air buoyancy correction should be made to the code mass. 3.1 Types
3.1.1 Static Gravity Force Standard Machine
This machine uses the gravity generated by the magnetic code as the standard load. It is automatically applied to the sensor under test in a certain order through appropriate mechanisms. This machine has high force value accuracy and small force value fluctuation. The force value accuracy of the machine mainly depends on the weighing accuracy and stability of the code, the measurement accuracy of gravity acceleration, and the measurement accuracy of the code and air density. It is also related to the material, surface treatment and unloading method of the silicon code. The force value accuracy of the machine is generally better than 5×10*5.3.1.2 Red sample # standard machine
This machine uses a lever to amplify the standard load produced by the standard weight. It is easier to obtain a larger force value than a static weight force standard machine. Its metrological performance mainly depends on the structure and combination of the lever, the structure of the blade and the knife bearing, and the quality of processing and installation. The force value accuracy of the machine is generally better than 5×10-4, and the force value complexity is not greater than 1×10,3.1.3 Hydraulic force standard
This machine uses a combination of a standard weight and two sets of pistons and cylinders to obtain a larger load through the principle of hydraulic amplification. Its metrological performance mainly depends on the structure, processing, installation, combination and motion state of the two sets of pistons and cylinders. The force value accuracy of the machine is generally better than 5×10-1
3.1.4 Loading device
3.1.4.1 Dead weight brick code
When the force value is relatively small, the code can be added to the sensor under test. It is essentially a dead weight force standard machine without a special loading mechanism.
3.1.4.2 Loading device
Use a force measuring instrument (group) with higher accuracy than the sensor under test as a standard, connect it in series with the sensor under test, and apply load by hydraulic or mechanical means. The force value accuracy of this device mainly depends on the accuracy index of the standard force measuring instrument (group), the performance of the loading mechanism, and the installation and installation.
3.2 Requirements
3.2.1 In principle, the relevant technical indicators of the force standard machine should be better than 3 times the corresponding indicators of the sensor under test. Select the appropriate force standard machine or loading device according to the test content and accuracy index of the sensor. 3.2.2 While requiring the force standard machine to have high accuracy and low non-repeatability, it is also required to have low position effect, low additional hysteresis on the sensor, be able to realize incremental and incremental load recognition and rapid loading and unloading, and have the force value stabilize quickly and be able to maintain for a sufficiently long time. 3.2.3 The standard machine should be calibrated or compared regularly to give its accuracy indicators such as force value accuracy and non-repeatability and related metrological performance.
4 Test method
&.1 Load characteristic test
Determine the zero output, rated output, pressure, non-repeatability, hysteresis, non-repeatability and comprehensive error according to the following procedures. GB 5604B5
4.1.1 Check whether the environmental conditions and test conditions of the test are consistent with this standard by comparing with the "test conditions" of the technical standard. 4.1.2 Place the sensor on the force standard machine and apply the frequency load 3 times. Each time, add the load to the rated load and then return to zero load. Note: When the load characteristics of the sensor are required to be tested without preload, this clause is not applicable. 4.1.3 If necessary, the electrical excitation can be tested or adjusted, the range and zero point of the indicating instrument can be adjusted, and the zero point output value can be read. After applying the preload 3 times, wait for 1 minute before conducting the formal test. 4.1.4
Apply increasing loads in the same increments until the rated load is reached. After each level of load is applied, keep it for a certain time and then read the output value. 4.1.5
Note: @) The load holding time can be 5s, 155, 0s and 1min. 30s is recommended. The other 3 times should be taken accurately. : When the loading conditions of the force standard machine are limited, the load increase is allowed to be different. The first level load is generally 10% to 20% of the rated load.
?The number of load levels shall not be less than 5 (excluding zero load point), and 10 levels are recommended. 4.1.6 After reaching the rated load, apply decreasing load in the same way and requirements as above. After each load level is reduced, keep it for a certain time (then note ① in 4.1.5), and then read the output value. 4.1.7 Return to zero load, keep it for 1 minute, and then read the zero output value. If necessary, readjust the zero point of the indicating instrument. Carry out steps 4.1.5 to 4.1.7 continuously for at least 3 times. 4.1.83
According to the above test results, refer to the following training formula to obtain the corresponding technical indicators (see figure). 4.1.9 According to the calibration curve, no complex 46R is set. Non-linear spring point output Figure 1 Calibration curve Zero point output 9 When expressed as a percentage of rated output: 100% rated output × 100% rated output Approximately. Rated load F is abbreviated as ~%FS (below). In China: GB5604-85 Rated output 6. — (9nir0.）
True line accuracy L
Hysteresis H:
A8L×10C%FS3
AeH.×100[%FS3
Unmeasured complexity R
Comprehensive error E
Number of torsion calibration cycles;
× 106 FS3
× 101[%FS」
an」—the output reading of zero load during the first (=1.2, m) measurement: 8alr——the withdrawal reading of rated load during the ith measurement: snack——the maximum value of the deviation between the process average calibration line and the average endpoint sound line; the maximum value of the deviation between the process average calibration curve and the process average calibration curve; AS
the maximum value of the output range of each load point during repeated calibration of a process A8. -The maximum deviation of the process average calibration curve and the process average calibration line from the average endpoint straight line. Note: The sensitivity of the strain sensor is also calculated by the following formula: 4.
The center is the mean value of the excitation voltage.
4.2 Crosstalk characteristic test
Determine the input resistance, output resistance and insulation resistance according to the above procedures: .2.1 Check whether the environmental conditions and test conditions of the test are consistent with this standard by comparing with the "test conditions of this standard". 4.2.2 Check and confirm that each connector of the sensor circuit is connected to the external circuit and maintains the circuit. 4.2.3 Connect the resistor to the input and output terminals of the sensor respectively, and read the value of the sensitive input and output resistance. (3)
4.4 Connect the megohmmeter to the input terminal and the external terminal, and read the megohm attenuation reading. If the input circuit and the output circuit are in an isolated state, connect the megohmmeter to the output terminal. On a head and a shell, measure its insulation resistance limit. Note: When there are no other special specifications, the voltage of the insulation resistance test is one V. The test conditions are different from the standard test conditions and should be noted.
4.3 Temperature characteristic test
Determine the zero point temperature effect and output temperature effect in the following sequence. 4.3.1 Check whether the environmental conditions and test conditions of the test are consistent with this standard by comparing them with the "Test Conditions" of this standard. 4.3.2 Place the sensor screen in the temperature chamber of the force standard machine (a section of the main cable of the sensor should be placed in the constant temperature chamber): 4.3.3 Apply the load 3 times, each time adding load to the rated load and then retreating to zero load. After applying the preload After that, read the vehicle for 1min, and then conduct the formal test:
4.3.4 If necessary, the electrical excitation can be tested or adjusted. Adjust the range and zero point of the indicator and read the zero output value. 4..5 Apply the rated load. After the rated load is applied, keep it for 30s and read the output value: return to zero, 1min at the same end, GB5604—85
Read the zero output value. If necessary, readjust the electrical excitation and the indicator instrument. Record the zero output value. Perform this step at least 3 times in a row.
4.3.6 The temperature of the high temperature box reaches the upper limit of the sensor compensation temperature range. Repeat 4.3.3~ after the temperature is fully stable. 4.3.5 step.
method: When the temperature of the thermostat does not reach the limit of the compensation temperature range, it is allowed to test with a temperature lower than the upper limit. 4.3.7 Lower the temperature of the thermostat until it reaches the lower limit of the sensor compensation temperature range. Repeat steps 4.3.3-4.3.5 after the temperature is fully stable.
Note: When the temperature of the thermostat does not reach the lower limit of the compensation temperature range, it is allowed to test with a temperature higher than the lower limit. 4.3.8 Restore the temperature of the thermostat to the standard test temperature. Repeat steps 4.3.3~4.3.4 after the temperature is fully stable. 4.3.9 Based on the above test results, refer to the following calculation formula to calculate the corresponding technical indicators. Ghh - fas
Effect of zero point temperature
enr - ,s
×100［%FS/10K］
（9）
×100［%FS10K]
(0n6- 6oh)-(0.5-gs)
Effect of output temperature
(0. -(,1) - (0ns -Hs)
T,-T，
-x100[%FS:10K]
X100C%FS:10K
In the formula, T, Ts, T, are the upper limit temperature, standard test temperature and leakage limit of the test respectively; goh, ess, 8s! are the zero point output corresponding to Th, , and 7, respectively: h, T and T! are respectively. The approximate value of the output reading under the corresponding rated load: When processing the test results of
, the absolute value of the sum of the two is taken as the standard for the zero-point temperature influence Z. S and S: The larger absolute value of the two is taken as the final output reduction influence method: ①D Under certain conditions, the zero-point source influence and output temperature influence are tested separately. When the "current width" obtained before and after the lifting and lowering is inconsistent, the pure results of these two times should be used for calculation respectively, and the larger absolute value is taken as the final corresponding humidity influence index. 14 Creep test
The following procedure determines the terminal creep and creep recovery. 4.1 Check whether the circulating current conditions and test conditions of the test are consistent with this standard by comparing with the "test conditions" of this standard. 4.4.2 The sensor is in compliance with the standard and the agent is applied Preload the load three times, then increase the load to the rated load and then back off to zero load. If the preload has an impact on the test results, the sensor should not be subjected to frequency load, and no load should be applied at least 24 hours before the test. GE5604—85
4.4.3 If necessary, the excitation can be tested or adjusted, the range and zero point of the indicating instrument can be adjusted, and the zero point output value can be read. 4.4.4 Apply the rated load as soon as possible (the load application time should generally not exceed 5 seconds, and it is best to apply a dead weight), read the output value immediately after the load is applied (it is recommended to be 5-10 seconds), and then read the output value in sequence at certain time intervals within 30 minutes. Take other output values. 4.4.5 Remove the rated load as soon as possible (the unloading time should generally not exceed 55), read the output immediately after the load is removed (5-10s is recommended), and then read other output values in sequence at certain time intervals within 3 minutes. 4.4.6 According to the above test results, refer to the following calculation formula to obtain the corresponding technical indicators (see Figure 2). Positive wax change
Some reading effects
Negative pass change
Positive creep change gas
Negative creep recovery
Figure 2 End change characteristics
fa-t,-
t+-ts-
一Time from zero load to rated load.
- Time from adding rated load to the first reading (5~10s). - Time to observe the transformer (30min).
±,, the time of removing load is approximately equal to,. ts-t.
t#-+s---
Where:
is the time from unloading to zero load to the first reading (5~105). Time to observe transformer recovery (min)
transformer CP
x100rFS
terminal transformer recovery C
,-rated output
8,* 0g- +3+ 8: B6
x100[%FS1
Time, t,13, t:, t6 corresponding output reading. (11)
(12)
Note: When the strain C is given, the load time (r+-t,) and the first operation time (r-f,) should be indicated. When the withstand recovery C is given, the unloading time (r+-t,) and the first reading time (r-f,) should be indicated. .5 Natural frequency test
Determine the natural frequency according to the following procedure.
GB 5804-85
4.5.1 Connect a suitable excitation power supply to the input end of the sensor (strain sensor is preferably a DC power supply) and connect a suitable oscilloscope to its output end.
4.5.2 Use an excitation device or other method to excite the force-bearing part of the sensor to generate self-vibration (for example, knocking with a lift). 4.5.3 Observe and record the waveform on the oscilloscope screen, and measure the natural vibration period T: Determine the natural frequency of the sensor by the following formula. fa
Note: Other instruments such as a perturbation table can also be used to measure the fixed vibration rate of the sensor. 4.8 Non-axial load test
Determine the effects of concentric load (including lateral load), central feed load and eccentric load according to the given procedure (this clause is only applicable to the compression direction of compression sensors or tension and compression dual-purpose sensors). 4.6.1 Check whether the environmental conditions and test conditions of the test are consistent with this standard by comparing with the "Test Conditions" of this standard. 4.6.2 Place the sensor on the force standard machine. 4.8.3 In order to determine the influence of concentric tilt load (including lateral load), two angles are respectively placed above and below the sensor (see Figure 3A), and the relative positions of the three are adjusted so that the sensor bears the concentric tilt load. The size of the tilt angle α is determined according to needs.
F,=Fs?
A: Schematic diagram of concentric tilt load (including lateral load) test
F-load
B: Schematic diagram of concentric tilt load test
F-load
Figure 3 Non-axial load test diagram
C, lateral load test diagram
, "lateral load
Apply preload 3 times, each time the load is added to the rated load and then returned to zero load. After 3 preloads, interval 1min, select 4.6 .4
Perform formal tests,
4.6.5 If necessary, the electrothermal ablation can be tested or adjusted. Adjust the range and zero point of the indicating instrument and read the zero output value. 4.6.6 Apply the rated load, maintain it for 30 seconds after the load is applied, and read the output value. 4.6. Remove the rated load, wait for 1 minute, and read the zero output value. GB5604---85
4.6.8 Rotate the sensor around its main axis three times in sequence, each time 90 degrees (that is, the force standard machine pressure pad position vector is consistent with The angle of the sensor position loss - referred to as the azimuth - changes from 0° to 90°, 180°, and 270°. After each rotation, repeat steps 4.6.5 to 4.6.7.
4.6.9 To determine the effect of eccentric tilt load, remove the wedge block placed above the sensor (see Figure 3B) and repeat steps 4.6.4 to 4.6.8. If the eccentricity is to be changed, the loading cylinder should be replaced with a convex end face, and a spacer should be placed between the convex end face and the upper surface of the sensor. By changing the chemical reaction of the sensor 4.6, 10 In order to determine the influence of eccentric load, the upper and lower pads of the obstacle removal sensor are fastened (see Figure 3C). The eccentricity is adjusted by changing the relative position between the sensor and the convex loading cylinder, and steps 4.6.4 to 4.6, 8 are repeated. 4.6.11 The errors caused by various non-axial negative flower effects are determined using the following formula (see Figure 3). dn
Where: 8—Error caused by a concentric tilt load: ,—Error caused by an eccentric tilt load; 8—Error caused by an eccentric load:
x 100[%FS]
x 100[%fS
I max× 100[%Fs]
8——When applying an eccentric tilt load with an inclination angle of α, when the azimuth angle is (=0, 90°, 180°, 270, at the same time, the sensor output;
2——When applying an eccentric tilt load with an inclination angle of α and an eccentricity of e, when the azimuth angle is, the sensor output, 3——When applying an eccentric load with an eccentricity of e, when the azimuth angle is Φ, the sensor output, rated output.
4.7 Non-center load testbzxZ.net
For beam sensors, taking into account special circumstances, special provisions are made (see Figure 1). User
GB5604-85
Figure 4 Schematic diagram of the action of the beam sensor
Magnification of the source
4. The load acting along the design direction of the load is marked as "center load" (see the arrow in Figure 4). 4.7.2 The load acting along the longitudinal geometric axis of the sensor is called "longitudinal load" (see the arrow in Figure 4). The measurement of the influence of eccentricity
"longitudinal load" is carried out by applying the allowable "longitudinal load" to the sensor and reading the offset of its zero point output. It is usually expressed as a percentage of the offset relative to the rated output. .7.3 The load acting along the intersection of the plane passing through the longitudinal geometric axis of the sensor and perpendicular to the "center load" action line and the plane passing through the "center load" action line and perpendicular to the longitudinal geometric axis is called "lateral load" (arrow in Figure 4): The measurement of the influence of "lateral load" is carried out by applying the allowable "lateral load" to the sensor and reading the offset of the sensor zero point. It is usually expressed as a percentage of the offset relative to the rated output. 4.7.4 The load whose action direction is parallel to the "center load" and whose action line intersects the longitudinal geometric axis is called "longitudinal eccentric load" (see ④ in Figure 4). The load whose action line intersects with the action line of the "central load" and the "lateral load" is called "lateral eccentric load" (see the arrow in Figure 4). The measurement of the influence of "longitudinal eccentric load" and "lateral eccentric load" is completed by applying the rated load in the specified direction and measuring the change in the rated output of the sensor. The percentage of the rated output is generally indicated by the modulator (the test result should indicate the change in the load). Additional remarks:
This standard was proposed by the National Bureau of Metrology
This standard was drafted by the Chinese Academy of Metrology. The main drafter of this standard is Li Shizhong.
This standard is entrusted to the Chinese Academy of Metrology for interpretation.4 The load whose action direction is parallel to the "central load" and whose action line intersects the longitudinal geometric axis is called "longitudinal eccentric load" (see ④ in Figure 4). The load whose action direction is parallel to the "central load" and whose action line intersects the action line of the "lateral load" is called "lateral eccentric load" (see arrow 4). The measurement of the influence of "longitudinal eccentric load" and "lateral eccentric load" is completed by applying the rated load in the specified direction and measuring the change in the rated output of the sensor. The percentage of the rated output is usually indicated (the test result should indicate the change). Additional remarks:
This standard was proposed by the National Bureau of Metrology
This standard was drafted by the Chinese Academy of Metrology. The main drafter of this standard is Li Shizhong.
This standard is entrusted to the Chinese Academy of Metrology for interpretation.4 The load whose action direction is parallel to the "central load" and whose action line intersects the longitudinal geometric axis is called "longitudinal eccentric load" (see ④ in Figure 4). The load whose action direction is parallel to the "central load" and whose action line intersects the action line of the "lateral load" is called "lateral eccentric load" (see arrow 4). The measurement of the influence of "longitudinal eccentric load" and "lateral eccentric load" is completed by applying the rated load in the specified direction and measuring the change in the rated output of the sensor. The percentage of the rated output is usually indicated (the test result should indicate the change). Additional remarks:
This standard was proposed by the National Bureau of Metrology
This standard was drafted by the Chinese Academy of Metrology. The main drafter of this standard is Li Shizhong.
This standard is entrusted to the Chinese Academy of Metrology for interpretation.
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