The test methods specified in this standard shall be adopted when detailed specifications of electromechanical components for electronic equipment within the scope of IEC/TC 48 are required. They may also be adopted when detailed specifications of similar components are required. GB/T 5095.2-1997 Basic test procedures and measurement methods for electromechanical components for electronic equipment Part 2: General inspection, electrical continuity and contact resistance tests, insulation tests and voltage stress tests GB/T5095.2-1997 Standard download decompression password: www.bzxz.net

GB/T 5095.2--1997
10 Basic test procedures and measurement methods Part 2: This standard is equivalent to IEC512-2:1985 "Electromechanical components for electronic equipment - Inspection, continuity, contact resistance test, insulation test and voltage stress test" and its amendment sheet 1 (1994). It is the first revision of (L J93, 2-86), and adds test 1c functional operation (switch). This standard is proposed by the Ministry of Electric Industry of the People's Republic of China. This standard is under the jurisdiction of the National Technical Committee for Standardization of Electromechanical Components for Electric Equipment. This standard was drafted by the Institute of Standardization of the Ministry of Electric Industry. The main drafters are: Yu Yufang, Zhi Qilong, Zhang Juhua, Wang Yutang. CB/T 5095.2—1997
IEC Foreword
1) The formal resolutions or agreements of IE (International Electromechanical Commission) on technical issues are formulated by the National Committees that are particularly concerned with these issues and participate in the Technical Committees. They represent the international consensus on the issues involved as much as possible. 2) These resolutions or agreements are published in the form of standards, technical reports or guidelines and are recommended for international use. In this sense, they are recognized by the National Committees.
3) In order to promote international unity, each IEC National Committee has the responsibility to adopt the IEC standard as much as possible in its national and regional standards. Any differences between the IFC standard and the corresponding national or regional standards should be indicated in the national or regional standards. IEC introduces
International Standard IC: S12-2 and 1EC/TC: 18 (Electromechanical Components for Electrical Equipment). The first edition of this standard replaces the first edition of 1EC 512-2 published in 1976 and its amendment 1 (1983) and the first supplementary IEC published in 1986 512-2A,
This standard is used together with Part 1: General Principles (IEC512-1:1984). The whole set of standards includes the following: Appendix A of IEC:512-1 gives the general plan. These test items will be published after they are formulated.
This standard is scheduled to replace 1EC:130-1 & Frequency below 3M IIz connector Part 1; General requirements and test methods X1 corresponding test items H. | |tt||This certification text is based on the following documents
Six-month method
48(CO)135
418(C)35wwW.bzxz.Net
18(CO)96
48(C)88
48(CO)278
48(C0)89
486002262
48(C0)90
48(C0 )9
48(CO)136
48(CO)232
Voting report
48(CO)159,169A
48(C0)10 9
28(00115
48(C0)106
28(C)285
48(CO)107
48(C0)264||t t||:8(C0)108
18(c)113
48(0)159
18(00)236
Two-month procedure
18(CO)150,150A
48(CO)129
Voting and standardizing The detailed information of this standard can be found in the voting report listed in the table above. This standard uses the following standards:
IEC 270:1981
Local effective electrical measurement
Voting report
48(CO)156
48(CO)154
National Standard of the People's Republic of China
Electromechanical components for electronic equipment
Basic test procedures and measuring methods
Part 2: General examination, electrical continuity and contact resistance tests, insulation tests and voltage stress tests
Part I
General examination
GB/T 5095.2—1997
idt IEC 512-2:1994
Replaces GB 5095. 2-86
The test force method specified in this standard shall be used when detailed specifications for electromechanical components for electronic equipment within the scope of IFC/TC48 are required. It may also be used when detailed specifications for similar components are required. 1 Test 1a; Appearance inspection
1.1 The purpose of this standard is to establish detailed standard test methods for inspecting the appearance of electromechanical components for electronic equipment. 1.2 General
Appearance inspection is to inspect whether the marking, appearance, quality and coating of the product conform to the relevant specifications. When detailed specifications are not available, the optical aids specified in 1.1 may be used. Appearance inspection is to a certain extent an observation method, so it should be carefully inspected to achieve a fair judgment. Defects that deviate from the standard or changes caused by stress should be carefully distinguished according to recurrence or effect. 1.3 Appearance features that need to be inspected
The inspection items of appearance features are as follows;
a) Workmanship quality and plating layer,
b) Marking:
TC48 standard: formulates international standards for components with electromechanical connection and switching functions used in "communication equipment and electronic devices using similar technologies".
1 R.F. connectors should not be from this technical committee, and are jointly formulated by TC:16 and H, F, and are formulated. 3 Sockets for core components such as crystals or electron tubes are approved by the State Administration of Technical Supervision on December 26, 1997 and implemented on October 1, 1998
c) Materials:
d) Surface processing quality. For example:
Scallop marks:
GB/T 5095.2—1997
Color (compared with relevant standard colors or samples); Gloss (compared with relevant standards, such as color scales or samples); Roughness, blemishes, ripples, scratches, wrinkles, pinholes, tiny pores, dents, protrusions, scratches, cracks, scratches, flash, etc.; Quality of embedded surfaces and closed surfaces; e) Internal state of translucent materials (such as cavities, air pools, fluid lines, fire debris); f) State and position of lubricants (visual inspection as much as possible); Looseness and separation of parts (especially 1.4 Visual inspection method
Perform visual inspection in accordance with the following methods: a) Visual inspection (at the most favorable viewing distance and under appropriate lighting conditions, with normal vision and color resolution). b) Inspection with a magnifying glass (if specified). For this standard, special inspection methods such as polarized light (to observe the internal tension of the material) or other indicators (to observe the internal cracks or fine pores of the material) are not allowed, except when the detailed specification has clear requirements. 1.5 Details to be specified
The detailed specification requires this item The following details shall be specified during the test: a) Details to be checked; b) Characteristics to be checked; c) Defect criteria; l) Magnification (if specified); c) Differences from the standard test method. 2 Test 1b: Dimensions and weight inspection 2.1 The purpose of this test is to establish detailed standard test methods for checking the dimensions and weight of electromechanical components used in electronic equipment: 2.2 General Dimensions and weight inspections are carried out in accordance with the relevant industry specifications with the aid of appropriate 2.3.1 Overall dimensions
Check whether the dimensions meet the requirements of the detailed specifications. 2.3.2 Weight
Check whether the weight meets the requirements of the detailed specifications. 2.3.3 Clearance and electrical distance
When the detailed specifications have provisions, the clearance and electrical distance should be checked, and their values ​​should meet the requirements of the relevant documents. 2.3.4 Detailed dimensions
When the detailed specifications have requirements. The detailed dimensions of the components to be checked should meet the requirements of the relevant drawings. 2.3.5.1.1.2.3.6.1.2.3.6.2.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.3.6.6.6.7.7.7.8.8.9 ...
b) Standard specification +
c) Other appropriate linear magnification projector: d) Quantitative microscope:
2.5 Details to be specified
Detailed specification requirements The following details should be specified in this test: a) Characteristic items to be inspected:
b) Standard specification details (if applicable):
c) Measuring equipment model and magnification;
l) Defect judgment band;
e) Differences from the standard test method 2his. Test 1c: Functional operation (switch)
2his.1's
is to establish a detailed standard test method to evaluate the function of each switching position of a switch under specified test conditions, as well as the function of associated external indicators (such as bulbs, light emitting diode indicators and liquid crystal displays) and components (such as solenoids, diodes, resistors) under specific operating conditions.
2his.2 Preparation of test samples
The test samples shall be prepared and installed in accordance with the provisions of the detailed specification. 2his.3 Test method
The test samples shall be connected to suitable displays and monitoring devices. The test equipment shall be able to check each switching position of the test sample. The test procedure shall comply with the provisions of the detailed specification. The components attached shall be checked for correct function. If the switch is delivered without these components, their connection devices shall be checked if possible. 2bis.4 Requirements
The functional operation of the switch, including the operation of any display components and/or structural parts, shall comply with the requirements of the detailed specification. 2his.5 Details to be specified
Detailed specification requirements The following details shall be specified for this test: a) Preparation of test samples;
b) Functional operation of the switch;
c) Differences from the standard test method. Part II Electrical continuity and contact resistance test 3 Test 2a: Contact resistance millivolt method
3.1 This test is to establish a detailed standard test method to measure the electrical resistance of a mating pair of contacts or of a contact mated with a measuring gauge. 3.2 General measurement requirements
Measurements may be made with direct current or alternating current. The frequency of the alternating current measurement shall not exceed 2kHz. In case of dispute, DC measurement shall prevail. The accuracy of the measuring equipment shall ensure that the total error is not greater than 10%. 3.3 Measurement method
3.3.1 Measurement of the voltage drop between the contact terminals (connection points specified in the detailed specification) is measured by a passband, thereby calculating the contact resistance. When the voltage is measured, the contact should not move. It must be noted that during the measurement process, abnormal pressure should be avoided on the contact under test, and the movement of the test cable should also be avoided. When the connection point specified in the detailed specification cannot be directly measured, the resistance value of the used resistor or wire should be subtracted from the measured value, and the corrected value should be recorded.
The contact to be measured should be selected according to the provisions of the detailed specification. 3.3.2 Test current and voltage
In order to prevent the insulation film on the contact from being broken down, the DC or AC peak value of the open circuit electromotive force of the test circuit should not exceed 20mV. The DC or AC test current should not exceed 100mA 3.4 Measurement cycle
3.4.1 Current measurement
A measurement cycle consists of the following:
a) Connect the contact;
h) Apply voltage;
c) Pass current in one direction for measurement;
d) Pass current in the opposite direction for measurement;
disconnect the power supply;
disconnect the contact.
3.4.2 AC measurement
A measurement cycle consists of the following:
a) Make contacts:
|) Apply current;
|t) Make measurements:
||c) Cut off power:
e) Disconnect contacts.
3. 4. 3 Multiple measurement cycles
When the detailed specification requires one or more measurement cycles, the cycles shall be carried out in close succession. Note: Unless otherwise specified, the contacts shall not be disturbed from the end of the previous test until the power is applied in this test or between any subsequent cycles.
3.5 Requirements
The measured contact resistance shall not exceed the value specified in the detailed specification. The contact resistance for DC measurement shall be the average of the two readings when the current is passed in the forward and reverse directions. Note: The test report shall indicate any differences from the standard test procedure. 3.6 Details to be specified Details The following specifications require that the following details should be specified for this test: a) Type and specification of the measuring wire connection point and its wire (if applicable); 6) For the matching components, the contacts to be measured and the number of measurement cycles; c) For a single mating contact, the number of measurements and the number of measurement cycles to be measured; d) Whether the contact is to be operated before the measurement and/or between each measurement cycle; e) The allowable range of contact resistance; 4 Test 2b: Contact resistance - 4.1 GB/T 5095.2-1997 specifies the test current method to establish a detailed standard test method to measure the resistance between the two ends of a single mating contact or between the contact and the measuring gauge. 4.2 General requirements for measurement are to be measured with direct current or alternating current. The frequency of the AC measurement shall not exceed 2 kV. In case of dispute, the blood flow measurement shall be used as the reference. The accuracy of the measuring equipment shall be such that the total error of the measurement shall not exceed 10%. 4.3 Measurement method
4.3.1 Measurement details
The voltage drop between the lead-out terminals of the contact (connection points specified by the detailed specification) is usually measured. When the contact resistance is calculated from the surface and the measured resistance is added, the contact will not move. It must be noted that during the measurement process, abnormal positive force should be avoided on the contact under test, and the movement of the test lead should also be avoided. When the connection points specified in the detailed specification cannot be measured directly, the torque value of the cable or wire used should be subtracted from the measurement position, and the hidden positive value should be recorded.
The contact to be measured should be selected according to the detailed specification. 4.3.2 Measurement of current and voltage
The contact resistance should be measured by passing the rated AC or DC current specified in the detailed specification. According to the provisions of the detailed specification, the peak value of the DC current of the power supply is not less than 1V. Each contact pair is tested when the test current is connected. 4.4 Measurement cycle
4.4.1 DC measurement
The composition of the measurement cycle is as follows:
a) Connect the contact:
h) Apply voltage;
c) Pass the current in one direction to measure;
c) Pass the current in the opposite direction to measure;
e) Cut off the power supply:
f) Disconnect the contact.
4.4.2 AC measurement
The composition of a measurement cycle is as follows:
a) Connect the contact:
b) Apply voltage:
e) Conduct the measurement:
d) Cut off the power supply;
e) Disconnect the contact.
4.4.3 Multiple measurement cycles
When the detailed specification requires two or more measurement cycles, the same measurement cycles shall be carried out continuously. Note: Unless otherwise specified, the contacts shall not be disturbed from the end of the previous test until the power is turned on in this test or between continuous measurement cycles.
4.5 Requirements
The measured contact resistance shall not exceed the value specified in the detailed specification. The contact resistance measured by direct current shall be the average of the two readings when the current flows in the forward and reverse directions. The test report shall include the differences from the standard test specifications. 4.6 Details to be specified
GB/T 5095.2-1997
Detailed specification requires that the following details be specified during the test: a) connection points of the measuring conductors and their conductor types and specifications (if applicable); c) the number of contacts and the number of measurement cycles required for mating contacts; d) whether the contacts need to be operated before measurement and/or between measurement cycles; t) the measured current; f) the permissible range of contact resistance; g) any differences from the standard test methods and (or) conditions. 5 Test 2c:Contact resistance change
is a standard test method specified in the specification: to measure the change in contact resistance of electromechanical components under specified dynamic conditions. This test is limited to electromechanical components with low contact resistance measured according to test 2a. 5.2 Installation of test samples
The test samples shall be installed in accordance with the requirements of the detailed specification. 5.3 General requirements
5.3.1 The change in contact resistance shall be determined according to the dynamic conditions. 5.3.2 The measurement of the change in contact resistance shall be carried out within the time specified in the relevant test and (or) detailed specification. 5.3.3 The DC current passing through during the measurement shall not exceed 50mA, and the electromotive force of the test circuit shall not exceed 20mV. 5.3.4 The change in contact resistance shall not exceed the value specified in 4 of the detailed specification. 5.4 Measuring equipment 5.4.1 Use a long-duration oscilloscope to display the voltage drop between the points specified by the detailed circuit to determine the change in contact resistance. 5.4.2 Test equipment requirements Predicted frequency response characteristics: The horizontal line is between 400Hz and 1MHz, and the error does not exceed 3dB. If an oscilloscope is used, its sensitivity should meet the following requirements: When measuring voltage up to 5tm and frequency up to 1MHz, the sensitivity is equal to or better than 50uV/cm. When measuring voltage up to 30m2 and frequency up to 1MHz, the sensitivity is equal to or better than 500uV/cm. When measuring voltage above 30m2 and frequency up to 1MHz, the sensitivity is equal to or better than 1.0mV/rm. 5.5 Details to be specified Detailed specifications require that the following details shall be specified for this test: a) Method of installation and wiring of the test sample, details of the wires and (or) wiring harness used; b) Range of variation of contact resistance; d) Severity of relevant dynamic tests; f) Contacts to be measured; 6 Test 2d: Microvolt circuit continuity (deleted) 7 Test 2e: Contact failure 7.1 GB/T 5095.2-1997 is a detailed standard test method to measure contact failures of electromechanical components under specified dynamic stress conditions. 7.2 Installation of test samples
The installation of test samples shall comply with the requirements of the detailed specification. 7.3 Measurement methods
7.3.1 Contact failures shall be measured under dynamic conditions. When the components are subjected to shock, impact, vibration or speed tests, the duration of the opening of closed contacts (contacts) and (or) the closing of open contacts (contacts) shall be measured. 7.3.2 The monitoring of contact failures shall be carried out within the scope specified in the relevant test and (or) detailed specification. It can be monitored for each contact or in one or more groups as specified in the detailed specification. When monitoring within a group, closed contacts (contacts) may be connected in series and open contacts (contacts) may be connected in parallel.
If the contact tested within the group fails, it is allowed to continue testing one by one. 7.4 Requirements
7.4.1 The test shall be carried out under the condition of a DC current not exceeding 150mA, and the dynamic potential shall not exceed 10V. 7.4.2 The duration of contact discharge shall not exceed the value specified in the relevant test and (or detailed specification. The preferred values ​​are as follows: 1k8, 10jes, 100x, Ims and 10ms
7.4.3 When the voltage drop across the closed contact (contact) exceeds 50% of the source electromotive force, the closed contact (contact) is considered to have failed. When the voltage drop across the open contact (contact) is less than 3% of the source electromotive force, the open contact (contact) is considered to have failed. 7.5 Details to be specified
The detailed specification requires that the following details be specified for this test: 1) The installation and wiring method of the test sample and the details of the cable or wire bundle to be used; h) Monitoring time, if different from the provisions of the relevant test method; ) Contacts to be monitored and their working conditions; d) Duration of contact failure rate:
e) Differences from standard test methods and (or) conditions. 8 Test 2f; Electrical Continuity of Enclosures
8.1 This test is a standard test method for establishing the electrical continuity of enclosures of components when mated. This test does not verify magnetic or radio frequency interference shielding. 8.2 General Requirements
8.2.1 Components having metal enclosures and providing circuit continuity when mated shall be measured as follows: 1. The measurement shall be made directly on the mating mating component. 2. The measurement shall be made on free-standing components connected to a short length of cable or conductor as specified in the detailed specification. 8.2.2 The resistance shall be measured across all series connections, for example: When one of a pair of mating components is of the fixed type, the measurement shall be made between the cable braid and/or enclosure and the mounting plate; when both are made of components, the measurement shall be made between the braids of the cable and/or enclosure; when both are made of components, the measurement shall be made between the braids of the cable and/or enclosure; when both are made of components, the measurement shall be made between the mounting plates. 8.2.3 The resistance shall be measured according to method 2b or 2. 8.3 Test requirements
The resistance value shall not be greater than the value specified in the detailed specification 8.4 The required provisions
The detailed specification requires that the following details shall be specified for this test: a) Installation of the test sample and connection method of the cable or wire harness: 6) Measuring point:
..comCB/T 5095.2
c) Test method (test 2h or 2a) and test current used: d) Maximum permissible core resistance value:
e) What are the differences from the standard test methods and (or) conditions? 9 Test 2g: Contact resistance stability (deleted) 10 Test 2h: Drive room mounting sleeve (surface) (ground) resistance 10.1H
is a detailed standard test method to determine the resistance between the metal drive of the switch and the mounting sleeve (the drive 1 is placed in it). 10.2 Measurement method
should be connected between the switch drive and the appropriate point outside the mounting sleeve. No external force should be applied to the drive during the resistance measurement. Before the test, the drive fiber can be fully cycled. During the test, the sense of movement of the differential drive is limited to the maximum value necessary for it to reach the next two measurement positions. For "rotating and closing", the resistance of the drive is measured at two positions as far apart as possible. For push-button switches, the resistance measurement should be made in the normal position of the drive. Or the resistance measurement should be made as specified in the detailed specification. The drive should be measured once in each test position. The electrical measurement should be carried out according to test 2a. 10.3 requires that the resistance value of any measurement should not exceed the value specified in the detailed specification. 10.4 Details to be specified The detailed specification requires that the following details should be specified for this test: a) The preferred measurement position of the drive (if different from that specified in 10.2): b) The maximum allowable resistance value:
) What are the differences from the standard test method? Part III Insulation test
11 Test 3; Insulation resistance
11. The purpose of this standard test is to establish detailed standard test methods to determine the insulation resistance of electromechanical components. 11.2 Installation of test samples Install the test samples in accordance with the requirements of the detailed specifications. 11.3 General requirements 11.3.1 Select method A, J or other methods in 11.4 to measure the insulation resistance in accordance with the provisions of the detailed specifications. The DC voltage of the circuit is 10V+1V, 100V±15V or 500V-=50V. 11.3.2 When measuring the insulation resistance, a stable value must be read. If the value reaches stability, read the value within 60s after correction. Note: If the value does not reach stability when recording the reading, it should be noted in the test report. 11.3.3 The insulation resistance should not be less than the value specified in the detailed specification. 11.4 Test method 11.4.1 Method A
The insulation resistance of the test sample is measured at the specified test voltage in turn between each tested lead-out terminal and all other leads connected to the housing and mounting plate.
11.4.2 Method 1
GB/ 5095.2-1997
First, alternately connect all the lead terminals of the test sample into two groups, and then apply the specified test voltage to measure the insulation resistance according to the following method. a) Between the first lead terminal and the second group connected to the housing or mounting plate: b) Between the second group of lead terminals and the first group connected to the housing or mounting plate. Note: When the lead terminals are arranged in two or more rows, in order to record the cable insulation resistance between each pair of adjacent lead terminals, two groups of two arrangements must be formed. 11.4.3
Apply the specified test voltage between adjacent lead terminals with the minimum spacing to measure the insulation resistance. 11.5 Details to be specified
Detailed specification requirements The following details should be specified for this test: a) Measurement method (see 11.4):
b) Test voltage value +
center) Minimum position of insulation resistance:
d) Tested connection:
e) Temperature:
f) Operating conditions, such as plugged in or unplugged state, etc.; g) What are the differences with the standard test methods and (or) conditions? Part 4 Voltage stress test
12 Test 4a: Withstand voltage
12.1 Purpose
To establish a detailed standard test method to determine the withstand capacity of electromechanical components when the specified test voltage is applied in accordance with the specified method. 12.2 Test sample installation
The test sample should be installed in accordance with the provisions of the detailed specification. 12.3 Test method
Select the following methods A, B or C according to the provisions of the detailed specification. Apply a vertical current or AC (peak) test voltage for 50s ± 5s. If it is an AC voltage, its frequency should be 45H2 ~ 60Hz, and the waveform should be approximately sinusoidal. The rate of applying the test voltage shall not exceed 1500V/5
12.3.1 Method A
Each lead of the test sample shall be subjected to the test voltage specified in the detailed specification between the other leads connected to the enclosure or mounting board in turn.
12.3.2 Method B
First, all the leads of the test sample are connected alternately to form two groups. In each group, there shall be no adjacent contacts (melting points). The test sample shall be subjected to the specified test voltage in turn. Between the first group of leads and the second group connected to the enclosure or mounting board: Between the first group of leads and the first group connected to the enclosure or mounting board: When the leads are arranged in two rows or more, in order to measure the withstand voltage between each pair of adjacent leads, another group of two arrangements must be placed. 12.3.3 Method C
The test sample is subjected to the test voltage between the adjacent leads specified in the detailed specification. 12.4 Test requirements
There should be no breakdown or arcing after the test discharge specified in the specification. The current does not exceed the maximum allowable value 12.5 Details that need to be specified
GB/T 5095.2-1997
Detailed specifications require that the following details be specified when testing items: n) Test method to be adopted:
1) Nature and value of test voltage;
) Maximum allowable leakage current (if required); d) Contacts to be tested:
) Environmental operation;
) When the test sample is open, the operating conditions should be specified: b) What are the differences from the standard test method (or) conditions: Note: For low gas and degradation properties, the derating system specified in the relevant general specification should be reported, and the test voltage should be reduced. 13 Test 4h: Partial discharge
13-1
is a standard test method that specifies details to assess the ability of a component to operate under specified positive voltage conditions without showing partial discharge. Note: This test is basically the same as IEC270 The test samples shall be wired and mounted in accordance with the detailed specifications. The operating conditions of the test samples, such as plugging or unplugging of connectors, switching on or off, shall be specified in the detailed specifications. 13.3 Test method
13.3.1 Test equipment
The basic circuit for measuring the flameout voltage of partial discharge is shown in Figure 1. The measurement circuit shall comply with the special requirements of electromechanical components with relatively small inductance and capacitance.
About the products
Test instruments
Figure 1 Test nozzle
The parameters of the equipment shown in the figure are as follows: Frequency of oscilloscope
Oscilloscope sensitivity
Time base scale
Capacitance C (including the capacitance of the oscilloscope body, wiring and coil)...Test voltage frequency
500kHz
2imm/mV10mm/mV
+2ms/scale
.. 20mH40mH
.80pF--120pF
40Hz60Hz
If necessary, a current limiting resistor (K,) can be used: In order to reduce the influence of the measuring device, a low impedance coupling can be used, and an amplifier can be used if necessary.
It must be ensured that the cable or wire used can meet the requirements higher than those of the test sample. 13.3.2 Test procedure
The applied test voltage shall be increased steadily until partial discharges can be detected on the oscilloscope. In order to determine the extinction voltage of partial discharges,
Tip: This standard content only shows part of the intercepted content of the complete standard. If you need the complete standard, please go to the top to download the complete standard document for free.