Some standard content:
GB18523--2001
All technical contents of this standard are mandatory. Former
This standard is a revision of the original GB9359.7--1988 "General Technical Conditions and Safety Requirements for Hydrological Instruments". The main revisions are as follows:
a) Added content related to environmental pollution, personal health, instruments and their carriers, and long-term unattended instruments in the "General Requirements";
b) Based on the technical experience accumulated in the scientific research, production and practical application of hydrological instruments for many years, and taking into account the application of many new technologies and new devices for hydrological instruments, this standard appropriately supplements and revises the relevant technical contents of weak current protection and instrument safety stipulated in the original standard;
c) The basic safety sign table in the original standard has been deleted and replaced by the text description of "Equipment Graphic Symbols" in the GB4793.1 standard. d) The electric strength test clause in the original standard has been deleted and replaced with a dielectric strength test, and the test content and method have been simplified to "should be carried out in accordance with the relevant provisions of Appendix D in GB4793.11995", e) This standard adds the content of "software and data security requirements". This standard replaces GB9359.7-1988 from the date of implementation. This standard is proposed by the Ministry of Water Resources.
The National Technical Committee for Hydrological Standardization Hydrological Instruments Technical Committee is responsible for this standard. This standard was drafted by Nanjing Water Resources and Hydrological Automation Research Institute. The main drafters of this standard are Shi Minghua, Xu Haifeng, Wang Zhiyi, and Lu Xu. This standard was first issued in December 1988 and revised for the first time in November 2001. This standard is entrusted to Nanjing Water Resources and Hydrological Automation Research Institute for interpretation. 665
1 Scope
National Standard of the People's Republic of China
Safety requirements for hydrologic instruments
General specificalion for hydrologic instrument safety requirements This standard specifies the general safety requirements for hydrologic instruments. This standard applies to various types of hydrologic instruments (hereinafter referred to as instruments). 2 Referenced standards
GB18523—2001
Replaces GB9359.71988
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards are subject to revision, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB4793.1-1995 Safety requirements for electrical equipment for measurement, control and laboratory use Part 1: General requirements (dt IEC 61010-1:1990)
GB6738-1986 Safety requirements for electrical measuring, indicating and recording instruments and their accessories (EQV60414:1973) GB/T6833.8--1987 Electromagnetic compatibility test specification for electronic measuring instruments - Working state magnetic field interference test GB/T6833.101987 Electromagnetic compatibility test specification for electronic measuring instruments - Radiated interference test SL.10-1989 Terminology of hydrological instruments
3 Definitions
The term definitions used in this standard are the same as those defined in GB6738, GB4793.1, GB/T6833.8, GB/T6833.10, SL10 and other standards.
4 Classification of product electrical safety levels
a) Instruments that are connected to a voltage exceeding extra-low voltage or are powered by the mains and have accessible conductive parts are Class 1 safety instruments; b) Instruments that are connected to a voltage exceeding extra-low voltage or are powered by the mains but do not have accessible conductive parts are Class I safety instruments; c) Instruments whose power supply voltage and internal voltage do not exceed the safety extra-low voltage or extra-low voltage are Class II safety instruments. 5 General requirements
5.1 The design and construction of the instrument should ensure that it will not cause danger to people or the surrounding environment under normal operation and possible failure or misoperation conditions.
5.2 The materials (such as isotopes) used by the instrument during normal testing and the energy or substances (such as electromagnetic radiation) released should not cause harm to the health of the operator, should not pollute the surrounding environment, and should not interfere with the normal operation of other nearby instruments. If the released energy or substance may affect the health of the operator in a confined space (refer to relevant national standards), it must be clearly stated in its instruction manual, and corresponding text descriptions or prominent warning signs must be placed on the instrument panel or other obvious locations. 5.3 The mechanical and electrical connection between the instrument and its carrier should ensure the safety of the carrier (vehicle, ship, cableway) and the instrument during transportation and testing (including extreme water flow conditions) and should not cause danger to people or the surrounding environment. And eye-catching operation marks should be placed during the testing process to remind passing vehicles and ships.
5.4 For instruments that are unattended for a long time, low-voltage DC power supply should be given priority to reduce unsafe factors. 6 Structural safety requirements
6.1 Stability and mechanical hazards
6.1.1 Under normal working conditions, the instability of the instrument structure should not bring danger to the operator or maintenance personnel. 6.1.2 The moving parts or energy storage parts of the instrument should be arranged or packaged reasonably. The moving parts of the instrument with obvious mechanical hazards (such as high-speed shafts, wheels, steel belts, etc.) should be equipped with outer covers or protective devices. Special ones can be equipped with keys or warning signs to avoid personal injury.
6.1.3 In addition to special functional requirements, the edges and corners of the instrument curtains, parts, etc. that may be touched by people should be rounded and smooth.
6.1.4 If the instrument is equipped with a handle or grip for moving, it should be able to withstand a force of 4 times the weight of the instrument, and there should be no obvious deformation or failure during the service life.
6.1.5 The outer shell or protective cover of the instrument should have measures to prevent moisture, dust and insect invasion. The instruments used underwater should have a sealed structure and the pressure resistance should exceed 50% of the rated working head. 6.1.6 The vehicles used for bridge measurement must have a mechanical safety device to prevent overturning. 6.2 Mechanical strength
6.2.1 The structure and materials of the instrument should have sufficient mechanical strength and should be able to withstand the changes of various severe climates in the use environment and possible improper operation.
6.2.2 The fixing device of the instrument fixed on the carrier should have sufficient strength and anti-vibration measures to prevent the instrument from failing, loosening or causing personal injury due to vibration during operation and impact during measurement under extreme water flow conditions. 6.2.3 The fixing devices of the instruments, instrument sensor components, antenna components and their signal cables fixed on outdoor buildings should have sufficient mechanical strength to withstand the changes of various severe climates in the use environment and should not cause damage to the instrument, loosening or causing personal injury. 6.2.4 The fixing devices of the instruments, instrument sensor components and their signal cables fixed underwater should have sufficient mechanical strength to prevent damage or loosening of the instrument due to water flow impact. 6.3 Protection
6.3.1 The structure and casing of Class I and Class II instruments should have good protection against electric shock to ensure that users do not accidentally come into contact with live parts.
General paint, enamel, ordinary paper, cotton fabric, metal oxide film and similar covering materials cannot be used as protective insulating layers. 6.3.2 Instruments powered by the mains power supply should be protected from overcurrent by fuses, circuit breakers, thermal circuit breakers or similar measures. 6.3.3 The scale of instrument readings and indications should be clear. The active light-emitting device of the instrument display device should have filtering measures to make it bright and not dazzling; for applications where its brightness contrast may be reduced under strong background light, a shading device should be added. 6.3.4 The instrument panel and operating table should not have large areas of reflection. 6.3.5 When the instrument has two or more indicator lights, the indicator light (cover) should be red, yellow, green and other colors according to different meanings.
Red: prohibition and emergency signal: warning of abnormal operation, overload, overheating, fault or operation error, high voltage connection, etc.; yellow: attention signal: indicates that the power is on; green: safety and permission signal: indicates that the instrument is working normally and can be operated. 6.3.6 The main operating mechanism should be set in an area where operation is convenient. The operating mechanism that issues emergency instructions should be set in a conspicuous position in the commonly used operation area. The control mechanism and its corresponding indicator light and display device should have an obvious position correspondence. 6.3.7 Generally, power sockets, fuse holders, fine-tuning mechanisms that are not frequently adjusted, and plug-in components that are not frequently plugged in and out should be set on the back panel.
GB 18523--2001
6.3.8 The AC and DC power input and output terminals on the instrument should use pin sockets, and the end of the power cord connected to the socket should use a hole plug: the insertion direction must be unique. Instruments using multiple power supplies should use different connectors to avoid wrong power connection. 6.3.9 The electrical connection between the instrument and its carrier should be safe and reliable and will not loosen due to vibration during operation. 6.4 Marking
6.4.1 All text symbols, graphic symbols, abbreviations, numbers, signs, physical quantities and unit symbols marked on the instrument should comply with the provisions of relevant standards.
6.4.2 The relationship between the operating direction of the control mechanism and the function mark should comply with the provisions of Table 1. Table 1
Operation mode and time
Function symbol
*", "on", "start", "increase", etc.
"off", "stop", "decrease", etc. Rotation
Clockwise
Counterclockwise
Direct reciprocation
6.4.3 When using multi-layer knobs on the instrument panel, the corresponding relationship between the knobs and the scales can be distinguished by color. 6.4.4 The color marking of the wires and insulating sleeves used in the electrical assembly of the instrument should refer to the relevant standards. 6.5 Test
In (press, push forward)
Out (pop up, release)
The test methods of 6.1.4 and 6.1.5 shall be carried out in accordance with the test methods specified in the respective product standards, and the rest shall be inspected by visual inspection. 7 Electrical safety requirements
7.1 Safety markings
7.1.1 The various safety markings used on the instrument shall be placed in the main position that is easy to see, and shall be clear and durable. 7.1.2 Basic safety markings shall comply with the relevant provisions of "Graphic symbols for equipment" in GB4793.1. 7.1.3 If the instrument is not equipped with a display device, it shall have an indicator light indicating that the power is on. When there is a power switch, the power supply should be indicated in words as *on* or *off
7.1.4 The fuse used in the instrument should indicate the rated value of the fuse current, and should be marked in a prominent place on or near the fuse. 7.1.5 The input and output terminals of the low-voltage DC power supply on the instrument, if using terminal blocks (rows) or socket-type wiring devices, should use red to represent the power supply "+", and green to represent the power supply "-", and indicate the voltage rating. 7.1.6 If a backup battery is installed on the instrument circuit board, its installation position should have a conspicuous "+" and "+" mark, and different sockets should be used when using dual power supplies.
7.2 Basic electrical protection
7.2.1 All easily touched conductive parts on the instrument's surface should not be hazardous live parts. 7.2.2 Metal handle switches are not allowed to be used as the power switch of the instrument. 7.2.3 Class 1 safety instruments must have a protective grounding terminal, and Class 1 safety instruments can have a functional grounding terminal. The protective grounding terminal should be able to withstand strong Corrosion, corrosion resistance can be obtained through appropriate coating and plating treatment. The connection resistance between the protective grounding terminal or grounding point and the parts required to be connected should not exceed 0.10.
7.2.4 The protective grounding wire can be bare or insulated. If it is insulated, except for the braided grounding wire which can be insulated with transparent insulation, the insulation of the other grounding wires should be yellow-green.
7.2.5 Instruments powered by batteries or as backup power supplies should prevent battery leakage and the accumulation of flammable gases. 7.2.6 External terminals or plugs should be equipped with covers or groove structures to prevent accidental short circuits. 7.2.7 According to the use environment of various instruments, the signal interface, antenna interface, telephone line interface and power input and output ports of the instrument and other devices that are susceptible to lightning strikes should take corresponding lightning protection measures. 7.2.8 The circuit and structure of the instrument should have effective protection measures against various industrial electromagnetic interference. 668
GB 18523--2001
7.2.9 The lightning protection grounding wire of the instrument should be reliably connected to the grounding grid, and the grounding resistance should not be greater than 100: For strong lightning strike areas, the grounding resistance should not be greater than 50.
7.3 Basic safety test
Basic safety test includes insulation resistance, leakage current and dielectric strength test. 7.3.1 Pretreatment
Place the instrument in an alternating heat and humidity test box with a relative humidity of 93% ± 2% or indoors for 48 hours of humidity treatment. At this time, the temperature should be controlled at a suitable temperature t between 20℃ and 30℃, and the variation range should not exceed 1℃, and no condensation should occur. 481 After that, The instrument is removed from the alternating damp heat test chamber and the following three basic tests are performed under normal atmospheric conditions. 7.3.2 Insulation resistance test
7.3.2.1 The insulation resistance test should be performed when the instrument power plug is not plugged into the main power supply and the instrument power switch is turned on. 7.3.2.2 Apply a 500V DC voltage between the primary circuit of the instrument power supply and the casing, and read the insulation resistance after the megohmmeter reading stabilizes for 5s.
a) For instruments with a protective grounding terminal (Class 1 safety instrument), the insulation resistance should not be less than 2Mo: b) For instruments without a protective grounding terminal (Class I safety instrument), the insulation resistance should not be less than 7Ma. 7.3.2.3 For instruments whose power supply voltage and internal voltage do not exceed the safety extra-low voltage (class safety instruments), apply a 100V DC voltage between the primary circuit of the power supply and the casing. After the megohmmeter reading stabilizes at 55, the insulation resistance should be no less than 1M0. 7.3.3 Leakage current test
Regardless of whether the instrument is connected in single phase or three phase, different test circuits are used for different power distribution factors. However, the measured leakage current of the instrument shall not exceed the following specified values:
Handheld Class I safety instrument: 0.75mA;
Mobile or fixed Class 1 safety instrument: 3.5mA; Class I safety instrument: 0.25mA;
For a system composed of several unit instruments connected to each primary power supply, each unit instrument shall be tested separately. A system composed of several unit instruments connected to the same primary power supply shall be tested as a single unit instrument. The following test shall be used for qualification inspection. A calibrated leakage current measuring instrument shall be used, and a power isolation transformer shall be used for testing.
For Class 1 instruments, all accessible conductive parts shall be tested. 7.3.3.1 For single-phase instruments with a rated voltage not exceeding 250V, the single-phase instruments and instruments using direct current shall be tested according to the circuit in Figure 1 if they are Class 1 safety instruments; and according to the circuit in Figure 2 if they are Class 2 safety instruments. Instrument under test or most sensitive conductor
Isolation transformer
Protective grounding terminal
Measuring instrument
Figure 1 Leakage current test circuit of Class 1 safety instrument connected in single phase 669
Isolation transformer
GB18523—2001
Reinforced insulation
Instrument under test
Not easy to touch conductor
Basic insulation,
Double insulation
Supplementary insulation
Measuring night
Figure 2 Leakage current test circuit of Class I safety instrument connected in single phase During the test, the conversion switch and the power switch of the instrument shall be disconnected or connected in various possible combinations, and the measured value shall not exceed its specified value.
7.3.3.2 For three-phase instruments with a single-phase rated voltage not exceeding 250V and instruments to be powered by two phase lines, if they are Class 1 safety instruments, the test shall be carried out according to the circuit in Figure 3.
Tested instrument or easily touched conductor
Isolation transformer
Protective grounding terminal
Measuring instrument
Figure 3 Three-phase connected Class I safety instrument leakage current test circuit 7.3.3.3 For instruments whose power supply voltage and internal voltage do not exceed the safety extra-low voltage, this test shall not be carried out. 7.3.4 Dielectric strength test
Should be carried out in accordance with the relevant provisions of Appendix D in GB4793.1--1995. 8 Software and data security requirements
The instrument itself should have safety protection and protection measures against accidental operating errors for application software programs, system data and measurement and collection data.
8.1 The instrument application software should be solidified in the non-volatile program memory. For storage chips with ultraviolet erasable windows, after writing the program, the window should be sealed with a light-shielding label to prevent the program from being lost. 8.2 The instrument application software should have a fault-tolerant function, so that it can automatically handle errors to prevent logical confusion and eliminate erroneous measurement data. 8.3 The measurement and storage instrument should have a hardware "watchdog" circuit and a software program trap to prevent "freeze" to ensure the normal operation of the instrument.
8.4 Instruments that need to initialize or modify system data (instrument operating parameters) should have a password or key lock setting function to prevent data loss or even instrument failure due to misoperation.1 All text symbols, graphic symbols, abbreviations, numbers, signs, physical quantities and unit symbols marked on the instrument shall comply with the provisions of relevant standards.
6.4.2 The relationship between the operating direction of the control mechanism and the function symbol shall comply with the provisions of Table 1. Table 1
Operation mode and direction
Function symbol
*", "on", "start", "increase", etc.
"off", "stop", "reduce", etc. Rotation
Clockwise
Counterclockwise
Direct reciprocation
6.4.3 When using multi-layer knobs on the instrument panel, colors can be used to distinguish the corresponding relationship between the knobs and the scales. 6.4.4 The color markings of the wires and insulating sleeves used in the electrical assembly of the instrument shall refer to relevant standards. 6.5 Testing
In (press, push forward)
Out (pop up, release)
The test methods of 6.1.4 and 6.1.5 shall be carried out in accordance with the test methods specified in the respective product standards, and the rest shall be inspected by visual inspection. 7 Electrical safety requirements
7.1 Safety markings
7.1.1 The various safety markings used on the instrument shall be placed in the main position that is easy to see, and shall be clear and durable. 7.1.2 Basic safety markings shall comply with the relevant provisions of "Graphic symbols for equipment" in GB4793.1. 7.1.3 If the instrument is not equipped with a display device, it shall have an indicator light indicating that the power is on. When there is a power switch, the power supply should be indicated in words as *on* or *off
7.1.4 The fuse used in the instrument should indicate the rated value of the fuse current, and should be marked in a prominent place on or near the fuse. 7.1.5 The input and output terminals of the low-voltage DC power supply on the instrument, if using terminal blocks (rows) or socket-type wiring devices, should use red to represent the power supply "+", and green to represent the power supply "-", and indicate the voltage rating. 7.1.6 If a backup battery is installed on the instrument circuit board, its installation position should have a conspicuous "+" and "+" mark, and different sockets should be used when using dual power supplies.
7.2 Basic electrical protection
7.2.1 All easily touched conductive parts on the instrument's surface should not be hazardous live parts. 7.2.2 Metal handle switches are not allowed to be used as the power switch of the instrument. 7.2.3 Class 1 safety instruments must have a protective grounding terminal, and Class 1 safety instruments can have a functional grounding terminal. The protective grounding terminal should be able to withstand strong Corrosion, corrosion resistance can be obtained through appropriate coating and plating treatment. The connection resistance between the protective grounding terminal or grounding point and the parts required to be connected should not exceed 0.10.
7.2.4 The protective grounding wire can be bare or insulated. If it is insulated, except for the braided grounding wire which can be insulated with transparent insulation, the insulation of the other grounding wires should be yellow-green.
7.2.5 Instruments powered by batteries or as backup power supplies should prevent battery leakage and the accumulation of flammable gases. 7.2.6 External terminals or plugs should be equipped with covers or groove structures to prevent accidental short circuits. 7.2.7 According to the use environment of various instruments, the signal interface, antenna interface, telephone line interface and power input and output ports of the instrument and other devices that are susceptible to lightning strikes should take corresponding lightning protection measures. 7.2.8 The circuit and structure of the instrument should have effective protection measures against various industrial electromagnetic interference. 668
GB 18523--2001
7.2.9 The lightning protection grounding wire of the instrument should be reliably connected to the grounding grid, and the grounding resistance should not be greater than 100: For strong lightning strike areas, the grounding resistance should not be greater than 50.
7.3 Basic safety test
Basic safety test includes insulation resistance, leakage current and dielectric strength test. 7.3.1 Pretreatment
Place the instrument in an alternating heat and humidity test box with a relative humidity of 93% ± 2% or indoors for 48 hours of humidity treatment. At this time, the temperature should be controlled at a suitable temperature t between 20℃ and 30℃, and the variation range should not exceed 1℃, and no condensation should occur. 481 After that, The instrument is removed from the alternating damp heat test chamber and the following three basic tests are performed under normal atmospheric conditions. 7.3.2 Insulation resistance test
7.3.2.1 The insulation resistance test should be performed when the instrument power plug is not plugged into the main power supply and the instrument power switch is turned on. 7.3.2.2 Apply a 500V DC voltage between the primary circuit of the instrument power supply and the casing, and read the insulation resistance after the megohmmeter reading stabilizes for 5s.
a) For instruments with a protective grounding terminal (Class 1 safety instrument), the insulation resistance should not be less than 2Mo: b) For instruments without a protective grounding terminal (Class I safety instrument), the insulation resistance should not be less than 7Ma. 7.3.2.3 For instruments whose power supply voltage and internal voltage do not exceed the safety extra-low voltage (class safety instruments), apply a 100V DC voltage between the primary circuit of the power supply and the casing. After the megohmmeter reading stabilizes at 55, the insulation resistance should be no less than 1M0. 7.3.3 Leakage current test
Regardless of whether the instrument is connected in single phase or three phase, different test circuits are used for different power distribution factors. However, the measured leakage current of the instrument shall not exceed the following specified values:
Handheld Class I safety instrument: 0.75mA;
Mobile or fixed Class 1 safety instrument: 3.5mA; Class I safety instrument: 0.25mA;
For a system composed of several unit instruments connected to each primary power supply, each unit instrument shall be tested separately. A system composed of several unit instruments connected to the same primary power supply shall be tested as a single unit instrument. The following test shall be used for qualification inspection. A calibrated leakage current measuring instrument shall be used, and a power isolation transformer shall be used for testing.
For Class 1 instruments, all accessible conductive parts shall be tested. 7.3.3.1 For single-phase instruments with a rated voltage not exceeding 250V, the single-phase instruments and instruments using direct current shall be tested according to the circuit in Figure 1 if they are Class 1 safety instruments; and according to the circuit in Figure 2 if they are Class 2 safety instruments. Instrument under test or most sensitive conductor
Isolation transformer
Protective grounding terminal
Measuring instrument
Figure 1 Leakage current test circuit of Class 1 safety instrument connected in single phase 669
Isolation transformer
GB18523—2001
Reinforced insulation
Instrument under test
Not easy to touch conductor
Basic insulation,
Double insulation
Supplementary insulation
Measuring night
Figure 2 Leakage current test circuit of Class I safety instrument connected in single phase During the test, the conversion switch and the power switch of the instrument shall be disconnected or connected in various possible combinations, and the measured value shall not exceed its specified value.
7.3.3.2 For three-phase instruments with a single-phase rated voltage not exceeding 250V and instruments to be powered by two phase lines, if they are Class 1 safety instruments, the test shall be carried out according to the circuit in Figure 3.
Tested instrument or easily touched conductor
Isolation transformer
Protective grounding terminal
Measuring instrument
Figure 3 Three-phase connected Class I safety instrument leakage current test circuit 7.3.3.3 For instruments whose power supply voltage and internal voltage do not exceed the safety extra-low voltage, this test shall not be carried out. 7.3.4 Dielectric strength test
Should be carried out in accordance with the relevant provisions of Appendix D in GB4793.1--1995. 8 Software and data security requirements
The instrument itself should have safety protection and protection measures against accidental operating errors for application software programs, system data and measurement and collection data. bzxz.net
8.1 The instrument application software should be solidified in the non-volatile program memory. For storage chips with ultraviolet erasable windows, after writing the program, the window should be sealed with a light-shielding label to prevent the program from being lost. 8.2 The instrument application software should have a fault-tolerant function, so that it can automatically handle errors to prevent logical confusion and eliminate erroneous measurement data. 8.3 The measurement and storage instrument should have a hardware "watchdog" circuit and a software program trap to prevent "freeze" to ensure the normal operation of the instrument.
8.4 Instruments that need to initialize or modify system data (instrument operating parameters) should have a password or key lock setting function to prevent data loss or even instrument failure due to misoperation.1 All text symbols, graphic symbols, abbreviations, numbers, signs, physical quantities and unit symbols marked on the instrument shall comply with the provisions of relevant standards.
6.4.2 The relationship between the operating direction of the control mechanism and the function symbol shall comply with the provisions of Table 1. Table 1
Operation mode and direction
Function symbol
*", "on", "start", "increase", etc.
"off", "stop", "reduce", etc. Rotation
Clockwise
Counterclockwise
Direct reciprocation
6.4.3 When using multi-layer knobs on the instrument panel, colors can be used to distinguish the corresponding relationship between the knobs and the scales. 6.4.4 The color markings of the wires and insulating sleeves used in the electrical assembly of the instrument shall refer to relevant standards. 6.5 Testing
In (press, push forward)
Out (pop up, release)
The test methods of 6.1.4 and 6.1.5 shall be carried out in accordance with the test methods specified in the respective product standards, and the rest shall be inspected by visual inspection. 7 Electrical safety requirements
7.1 Safety markings
7.1.1 The various safety markings used on the instrument shall be placed in the main position that is easy to see, and shall be clear and durable. 7.1.2 Basic safety markings shall comply with the relevant provisions of "Graphic symbols for equipment" in GB4793.1. 7.1.3 If the instrument is not equipped with a display device, it shall have an indicator light indicating that the power is on. When there is a power switch, the power supply should be indicated in words as *on* or *off
7.1.4 The fuse used in the instrument should indicate the rated value of the fuse current, and should be marked in a prominent place on or near the fuse. 7.1.5 The input and output terminals of the low-voltage DC power supply on the instrument, if using terminal blocks (rows) or socket-type wiring devices, should use red to represent the power supply "+", and green to represent the power supply "-", and indicate the voltage rating. 7.1.6 If a backup battery is installed on the instrument circuit board, its installation position should have a conspicuous "+" and "+" mark, and different sockets should be used when using dual power supplies.
7.2 Basic electrical protection
7.2.1 All easily touched conductive parts on the instrument's surface should not be hazardous live parts. 7.2.2 Metal handle switches are not allowed to be used as the power switch of the instrument. 7.2.3 Class 1 safety instruments must have a protective grounding terminal, and Class 1 safety instruments can have a functional grounding terminal. The protective grounding terminal should be able to withstand strong Corrosion, corrosion resistance can be obtained through appropriate coating and plating treatment. The connection resistance between the protective grounding terminal or grounding point and the parts required to be connected should not exceed 0.10.
7.2.4 The protective grounding wire can be bare or insulated. If it is insulated, except for the braided grounding wire which can be insulated with transparent insulation, the insulation of the other grounding wires should be yellow-green.
7.2.5 Instruments powered by batteries or as backup power supplies should prevent battery leakage and the accumulation of flammable gases. 7.2.6 External terminals or plugs should be equipped with covers or groove structures to prevent accidental short circuits. 7.2.7 According to the use environment of various instruments, the signal interface, antenna interface, telephone line interface and power input and output ports of the instrument and other devices that are susceptible to lightning strikes should take corresponding lightning protection measures. 7.2.8 The circuit and structure of the instrument should have effective protection measures against various industrial electromagnetic interference. 668
GB 18523--2001
7.2.9 The lightning protection grounding wire of the instrument should be reliably connected to the grounding grid, and the grounding resistance should not be greater than 100: For strong lightning strike areas, the grounding resistance should not be greater than 50.
7.3 Basic safety test
Basic safety test includes insulation resistance, leakage current and dielectric strength test. 7.3.1 Pretreatment
Place the instrument in an alternating heat and humidity test box with a relative humidity of 93% ± 2% or indoors for 48 hours of humidity treatment. At this time, the temperature should be controlled at a suitable temperature t between 20℃ and 30℃, and the variation range should not exceed 1℃, and no condensation should occur. 481 After that, The instrument is removed from the alternating damp heat test chamber and the following three basic tests are performed under normal atmospheric conditions. 7.3.2 Insulation resistance test
7.3.2.1 The insulation resistance test should be performed when the instrument power plug is not plugged into the main power supply and the instrument power switch is turned on. 7.3.2.2 Apply a 500V DC voltage between the primary circuit of the instrument power supply and the casing, and read the insulation resistance after the megohmmeter reading stabilizes for 5s.
a) For instruments with a protective grounding terminal (Class 1 safety instrument), the insulation resistance should not be less than 2Mo: b) For instruments without a protective grounding terminal (Class I safety instrument), the insulation resistance should not be less than 7Ma. 7.3.2.3 For instruments whose power supply voltage and internal voltage do not exceed the safety extra-low voltage (class safety instruments), apply a 100V DC voltage between the primary circuit of the power supply and the casing. After the megohmmeter reading stabilizes at 55, the insulation resistance should be no less than 1M0. 7.3.3 Leakage current test
Regardless of whether the instrument is connected in single phase or three phase, different test circuits are used for different power distribution factors. However, the measured leakage current of the instrument shall not exceed the following specified values:
Handheld Class I safety instrument: 0.75mA;
Mobile or fixed Class 1 safety instrument: 3.5mA; Class I safety instrument: 0.25mA;
For a system composed of several unit instruments connected to each primary power supply, each unit instrument shall be tested separately. A system composed of several unit instruments connected to the same primary power supply shall be tested as a single unit instrument. The following test shall be used for qualification inspection. A calibrated leakage current measuring instrument shall be used, and a power isolation transformer shall be used for testing.
For Class 1 instruments, all accessible conductive parts shall be tested. 7.3.3.1 For single-phase instruments with a rated voltage not exceeding 250V, the single-phase instruments and instruments using direct current shall be tested according to the circuit in Figure 1 if they are Class 1 safety instruments; and according to the circuit in Figure 2 if they are Class 2 safety instruments. Instrument under test or most sensitive conductor
Isolation transformer
Protective grounding terminal
Measuring instrument
Figure 1 Leakage current test circuit of Class 1 safety instrument connected in single phase 669
Isolation transformer
GB18523—2001
Reinforced insulation
Instrument under test
Not easy to touch conductor
Basic insulation,
Double insulation
Supplementary insulation
Measuring night
Figure 2 Leakage current test circuit of Class I safety instrument connected in single phase During the test, the conversion switch and the power switch of the instrument shall be disconnected or connected in various possible combinations, and the measured value shall not exceed its specified value.
7.3.3.2 For three-phase instruments with a single-phase rated voltage not exceeding 250V and instruments to be powered by two phase lines, if they are Class 1 safety instruments, the test shall be carried out according to the circuit in Figure 3.
Tested instrument or easily touched conductor
Isolation transformer
Protective grounding terminal
Measuring instrument
Figure 3 Three-phase connected Class I safety instrument leakage current test circuit 7.3.3.3 For instruments whose power supply voltage and internal voltage do not exceed the safety extra-low voltage, this test shall not be carried out. 7.3.4 Dielectric strength test
Should be carried out in accordance with the relevant provisions of Appendix D in GB4793.1--1995. 8 Software and data security requirements
The instrument itself should have safety protection and protection measures against accidental operating errors for application software programs, system data and measurement and collection data.
8.1 The instrument application software should be solidified in the non-volatile program memory. For storage chips with ultraviolet erasable windows, after writing the program, the window should be sealed with a light-shielding label to prevent the program from being lost. 8.2 The instrument application software should have a fault-tolerant function, so that it can automatically handle errors to prevent logical confusion and eliminate erroneous measurement data. 8.3 The measurement and storage instrument should have a hardware "watchdog" circuit and a software program trap to prevent "freeze" to ensure the normal operation of the instrument.
8.4 Instruments that need to initialize or modify system data (instrument operating parameters) should have a password or key lock setting function to prevent data loss or even instrument failure due to misoperation.4 The color marking of the wires and insulating sleeves used in the electrical assembly of the instrument shall refer to the relevant standards. 6.5 Test
Entry (press, push forward)
Exit (pop out, release)
The test methods of 6.1.4 and 6.1.5 shall be carried out in accordance with the test methods specified in the respective product standards, and the rest shall be inspected by visual inspection. 7 Electrical safety requirements
7.1 Safety markings
7.1.1 The various safety markings used on the instrument shall be placed in the main position that is easy to see, and shall be clear and durable. 7.1.2 The basic safety markings shall comply with the relevant provisions of "graphic symbols for equipment" in GB4793.1. 7.1.3 If the instrument is not equipped with a display device, it shall have an indicator light indicating that the power is on. When equipped with a power switch, the power supply shall be indicated in words as "on" or "off".
7.1.4 The fuse used in the instrument shall indicate the rated value of the fuse current, and shall be marked in a prominent place on or near the fuse. 7.1.5 If the input and output terminals of the low-voltage DC power supply on the instrument use terminal blocks (rows) or socket-type wiring devices, red should represent the power supply "+", white should represent the power supply "-", and indicate the voltage rating. 7.1.6 If a backup battery is installed on the instrument circuit board, its installation position should have a conspicuous "+" and "+" mark, and different sockets should be used when using dual power supplies.
7.2 Basic electrical protection
7.2.1 All easily touched conductive parts on the instrument's surface should not be dangerous live parts. 7.2.2 Metal handle switches are not allowed to be used for the instrument's power switch. 7.2.3 Class 1 safety instruments must have a protective grounding terminal, and Class 1 safety instruments can have a functional grounding terminal. The protective grounding terminal should be resistant to strong corrosion, and the corrosion resistance can be obtained through appropriate coating and plating. The connection resistance between the protective grounding terminal or grounding point and the parts required to be connected should not exceed 0.10.
7.2.4 The protective grounding wire can be bare or insulated. If insulated, except for the braided grounding wire which can be insulated with transparent insulation, the insulation of the other grounding wires should be yellow-green.
7.2.5 Instruments powered by batteries or as backup power sources should prevent battery leakage and the collection of flammable gases. 7.2.6 External terminals or plugs should be equipped with covers or groove structures to prevent accidental short circuits. 7.2.7 According to the use environment of various instruments, the signal interface, antenna interface, telephone line interface, power input and output ports of the instrument and other devices that are susceptible to lightning strikes should take corresponding lightning protection measures. 7.2.8 The instrument should have effective protection measures against various industrial electromagnetic interference in circuits and structures. 668
GB 18523--2001
7.2.9 The lightning protection grounding wire of the instrument should be reliably connected to the grounding network, and the grounding resistance should not be greater than 100: For strong lightning strike areas, the grounding resistance should not be greater than 50.
7.3 Basic safety test
Basic safety test includes the test of insulation resistance, leakage current and dielectric strength. 7.3.1 Pretreatment
Place the instrument in an alternating damp heat test chamber with a relative humidity of 93%±2% or indoors for 48h of humidity treatment. At this time, the temperature should be controlled at a suitable temperature t between 20℃ and 30℃, and its variation range should not exceed 1℃, and no condensation should occur. After 481, move the instrument out of the alternating damp heat test chamber and perform the following three basic tests under normal atmospheric conditions. 7.3.2 Insulation resistance test
7.3.2.1 The insulation resistance test should be carried out when the instrument power plug is not plugged into the main power supply and the instrument power switch is turned on. 7.3.2.2 Apply a 500V DC voltage between the primary circuit of the instrument power supply and the casing, and read the insulation resistance after the megohmmeter reading is stable for 5s.
a) For instruments with protective grounding terminals (Class 1 safety instruments), the insulation resistance shall not be less than 2Mo: b) For instruments without protective grounding terminals (Class I safety instruments), the insulation resistance shall not be less than 7Ma. 7.3.2.3 For instruments whose power supply voltage and internal voltage do not exceed the safety extra-low voltage (Class I safety instruments), apply a 100V DC voltage between the primary circuit of the power supply and the casing. After the megohmmeter reading stabilizes at 55, the insulation resistance shall be no less than 1M0. 7.3.3 Leakage current test
Whether it is a single-phase or three-phase connected instrument, different test circuits are used for different power distribution factors. However, the measured leakage current of the instrument shall not exceed the following specified values:
Handheld Class I safety instrument: 0.75mA;
Mobile or fixed Class 1 safety instrument: 3.5mA; Class I safety instrument: 0.25mA;
For a system composed of several unit instruments interconnected with each other with a primary power supply line, each unit instrument shall be tested separately. A system consisting of several unit instruments interconnected to a common primary power supply shall be tested as a single unit instrument. Compliance shall be checked by the following test. A calibrated and qualified measuring instrument for measuring leakage current shall be used and a power isolation transformer shall be used for the test.
All accessible conductive parts of Class 1 instruments shall be tested. 7.3.3.1 For single-phase instruments with a rated voltage not exceeding 250V, single-phase instruments and instruments using direct current shall be tested as single-phase instruments. If they are Class 1 safety instruments, they shall be tested according to the circuit in Figure 1. If they are Class 1 safety instruments, they shall be tested according to the circuit in Figure 2. Instrument under test or most sensitive conductor
Isolation transformer
Protective grounding terminal
Measuring instrument
Figure 1 Leakage current test circuit of Class 1 safety instrument connected in single phase 669
Isolation transformer
GB18523—2001
Reinforced insulation
Instrument under test
Not easy to touch conductor
Basic insulation,
Double insulation
Supplementary insulation
Measuring night
Figure 2 Leakage current test circuit of Class I safety instrument connected in single phase During the test, the conversion switch and the power switch of the instrument shall be disconnected or connected in various possible combinations, and the measured value shall not exceed its specified value.
7.3.3.2 For three-phase instruments with a single-phase rated voltage not exceeding 250V and instruments to be powered by two phase lines, if they are Class 1 safety instruments, the test shall be carried out according to the circuit in Figure 3.
Tested instrument or easily touched conductor
Isolation transformer
Protective grounding terminal
Measuring instrument
Figure 3 Three-phase connected Class I safety instrument leakage current test circuit 7.3.3.3 For instruments whose power supply voltage and internal voltage do not exceed the safety extra-low voltage, this test shall not be carried out. 7.3.4 Dielectric strength test
Should be carried out in accordance with the relevant provisions of Appendix D in GB4793.1--1995. 8 Software and data security requirements
The instrument itself should have safety protection and protection measures against accidental operating errors for application software programs, system data and measurement and collection data.
8.1 The instrument application software should be solidified in the non-volatile program memory. For storage chips with ultraviolet erasable windows, after writing the program, the window should be sealed with a light-shielding label to prevent the program from being lost. 8.2 The instrument application software should have a fault-tolerant function, so that it can automatically handle errors to prevent logical confusion and eliminate erroneous measurement data. 8.3 The measurement and storage instrument should have a hardware "watchdog" circuit and a software program trap to prevent "freeze" to ensure the normal operation of the instrument.
8.4 Instruments that need to initialize or modify system data (instrument operating parameters) should have a password or key lock setting function to prevent data loss or even instrument failure due to misoperation.4 The color marking of the wires and insulating sleeves used in the electrical assembly of the instrument shall refer to the relevant standards. 6.5 Test
Entry (press, push forward)
Exit (pop out, release)
The test methods of 6.1.4 and 6.1.5 shall be carried out in accordance with the test methods specified in the respective product standards, and the rest shall be inspected by visual inspection. 7 Electrical safety requirements
7.1 Safety markings
7.1.1 The various safety markings used on the instrument shall be placed in the main position that is easy to see, and shall be clear and durable. 7.1.2 The basic safety markings shall comply with the relevant provisions of "graphic symbols for equipment" in GB4793.1. 7.1.3 If the instrument is not equipped with a display device, it shall have an indicator light indicating that the power is on. When equipped with a power switch, the power supply shall be indicated in words as "on" or "off".
7.1.4 The fuse used in the instrument shall indicate the rated value of the fuse current, and shall be marked in a prominent place on or near the fuse. 7.1.5 If the input and output terminals of the low-voltage DC power supply on the instrument use terminal blocks (rows) or socket-type wiring devices, red should represent the power supply "+", white should represent the power supply "-", and indicate the voltage rating. 7.1.6 If a backup battery is installed on the instrument circuit board, its installation position should have a conspicuous "+" and "+" mark, and different sockets should be used when using dual power supplies.
7.2 Basic electrical protection
7.2.1 All easily touched conductive parts on the instrument's surface should not be dangerous live parts. 7.2.2 Metal handle switches are not allowed to be used for the instrument's power switch. 7.2.3 Class 1 safety instruments must have a protective grounding terminal, and Class 1 safety instruments can have a functional grounding terminal. The protective grounding terminal should be resistant to strong corrosion, and the corrosion resistance can be obtained through appropriate coating and plating. The connection resistance between the protective grounding terminal or grounding point and the parts required to be connected should not exceed 0.10.
7.2.4 The protective grounding wire can be bare or insulated. If insulated, except for the braided grounding wire which can be insulated with transparent insulation, the insulation of the other grounding wires should be yellow-green.
7.2.5 Instruments powered by batteries or as backup power sources should prevent battery leakage and the collection of flammable gases. 7.2.6 External terminals or plugs should be equipped with covers or groove structures to prevent accidental short circuits. 7.2.7 According to the use environment of various instruments, the signal interface, antenna interface, telephone line interface, power input and output ports of the instrument and other devices that are susceptible to lightning strikes should take corresponding lightning protection measures. 7.2.8 The instrument should have effective protection measures against various industrial electromagnetic interference in circuits and structures. 668
GB 18523--2001
7.2.9 The lightning protection grounding wire of the instrument should be reliably connected to the grounding network, and the grounding resistance should not be greater than 100: For strong lightning strike areas, the grounding resistance should not be greater than 50.
7.3 Basic safety test
Basic safety test includes the test of insulation resistance, leakage current and dielectric strength. 7.3.1 Pretreatment
Place the instrument in an alternating damp heat test chamber with a relative humidity of 93%±2% or indoors for 48h of humidity treatment. At this time, the temperature should be controlled at a suitable temperature t between 20℃ and 30℃, and its variation range should not exceed 1℃, and no condensation should occur. After 481, move the instrument out of the alternating damp heat test chamber and perform the following three basic tests under normal atmospheric conditions. 7.3.2 Insulation resistance test
7.3.2.1 The insulation resistance test should be carried out when the instrument power plug is not plugged into the main power supply and the instrument power switch is turned on. 7.3.2.2 Apply a 500V DC voltage between the primary circuit of the instrument power supply and the casing, and read the insulation resistance after the megohmmeter reading is stable for 5s.
a) For instruments with protective grounding terminals (Class 1 safety instruments), the insulation resistance shall not be less than 2Mo: b) For instruments without protective grounding terminals (Class I safety instruments), the insulation resistance shall not be less than 7Ma. 7.3.2.3 For instruments whose power supply voltage and internal voltage do not exceed the safety extra-low voltage (Class I safety instruments), apply a 100V DC voltage between the primary circuit of the power supply and the casing. After the megohmmeter reading stabilizes at 55, the insulation resistance shall be no less than 1M0. 7.3.3 Leakage current test
Whether it is a single-phase or three-phase connected instrument, different test circuits are used for different power distribution factors. However, the measured leakage current of the instrument shall not exceed the following specified values:
Handheld Class I safety instrument: 0.75mA;
Mobile or fixed Class 1 safety instrument: 3.5mA; Class I safety instrument: 0.25mA;
For a system composed of several unit instruments interconnected with each other with a primary power supply line, each unit instrument shall be tested separately. A system consisting of several unit instruments interconnected to a common primary power supply shall be tested as a single unit instrument. Compliance shall be checked by the following test. A calibrated and qualified measuring instrument for measuring leakage current shall be used and a power isolation transformer shall be used for the test.
All accessible conductive parts of Class 1 instruments shall be tested. 7.3.3.1 For single-phase instruments with a rated voltage not exceeding 250V, single-phase instruments and instruments using direct current shall be tested as single-phase instruments. If they are Class 1 safety instruments, they shall be tested according to the circuit in Figure 1. If they are Class 1 safety instruments, they shall be tested according to the circuit in Figure 2. Instrument under test or most sensitive conductor
Isolation transformer
Protective grounding terminal
Measuring instrument
Figure 1 Leakage current test circuit of Class 1 safety instrument connected in single phase 669
Isolation transformer
GB18523—2001
Reinforced insulation
Instrument under test
Not easy to touch conductor
Basic insulation,
Double insulation
Supplementary insulation
Measuring night
Figure 2 Leakage current test circuit of Class I safety instrument connected in single phase During the test, the conversion switch and the power switch of the instrument shall be disconnected or connected in various possible combinations, and the measured value shall not exceed its specified value.
7.3.3.2 For three-phase instruments with a single-phase rated voltage not exceeding 250V and instruments to be powered by two phase lines, if they are Class 1 safety instruments, the test shall be carried out according to the circuit in Figure 3.
Tested instrument or easily touched conductor
Isolation transformer
Protective grounding terminal
Measuring instrument
Figure 3 Three-phase connected Class I safety instrument leakage current test circuit 7.3.3.3 For instruments whose power supply voltage and internal voltage do not exceed the safety extra-low voltage, this test shall not be carried out. 7.3.4 Dielectric strength test
Should be carried out in accordance with the relevant provisions of Appendix D in GB4793.1--1995. 8 Software and data security requirements
The instrument itself should have safety protection and protection measures against accidental operating errors for application software programs, system data and measurement and collection data.
8.1 The instrument application software should be solidified in the non-volatile program memory. For storage chips with ultraviolet erasable windows, after writing the program, the window should be sealed with a light-shielding label to prevent the program from being lost. 8.2 The instrument application software should have a fault-tolerant function, so that it can automatically handle errors to prevent logical confusion and eliminate erroneous measurement data. 8.3 The measurement and storage instrument should have a hardware "watchdog" circuit and a software program trap to prevent "freeze" to ensure the normal operation of the instrument.
8.4 Instruments that need to initialize or modify system data (instrument operating parameters) should have a password or key lock setting function to prevent data loss or even instrument failure due to misoperation.2 Basic electrical protection
7.2.1 All easily touched conductive parts on the instrument surface should not be dangerous live parts. 7.2.2 Metal handle switches are not allowed to be used for the power switch of the instrument. 7.2.3 Class 1 safety instruments must have a protective grounding terminal, and Class 1 safety instruments can have a functional grounding terminal. The protective grounding terminal should be resistant to strong corrosion, and the corrosion resistance can be obtained through appropriate coating and plating treatment. The connection resistance between the protective grounding terminal or grounding point and the parts required to be connected should not exceed 0.10.
7.2.4 The protective grounding wire can be bare or insulated. If insulated, except for the braided grounding wire, which can be insulated with transparent insulation, the insulation of the other grounding wires should be yellow-green.
7.2.5 Instruments powered by batteries or as backup power supplies should prevent battery leakage and the collection of flammable gases. 7.2.6 External terminals or plugs should be equipped with covers or groove structures to prevent accidental short circuits. 7.2.7 According to the use environment of various instruments, the signal interface, antenna interface, telephone line interface and power input and output port of the instrument and other devices susceptible to lightning strikes should adopt corresponding lightning protection measures. 7.2.8 The instrument should have effective protection measures against various industrial electromagnetic interference in circuit and structure. 668
GB 18523--2001
7.2.9 The lightning protection grounding wire of the instrument should be reliably connected to the grounding network, and the grounding resistance should not be greater than 100: For strong lightning strike areas, the grounding resistance should not be greater than 50.
7.3 Basic safety test
Basic safety test includes insulation resistance, leakage current and dielectric strength test. 7.3.1 Pretreatment
Place the instrument in an alternating damp heat test chamber with a relative humidity of 93%±2% or indoors for 48h of humidity treatment. At this time, the temperature should be controlled at a suitable temperature t between 20℃ and 30℃, and the variation range should not exceed 1℃, and no condensation should occur. After 481, remove the instrument from the alternating damp heat test chamber and perform the following three basic tests under normal atmospheric conditions. 7.3.2 Insulation resistance test
7.3.2.1 The insulation resistance test should be performed when the instrument power plug is not plugged into the main power supply and the instrument power switch is turned on. 7.3.2.2 Apply a 500V DC voltage between the primary circuit of the instrument power supply and the casing, and read the insulation resistance after the megohmmeter reading is stable for 5s.
a) For instruments with protective grounding terminals (Class 1 safety instruments), the insulation resistance should not be less than 2Mo: b) For instruments without protective grounding terminals (Class I safety instruments), the insulation resistance should not be less than 7Ma. 7.3.2.3 For instruments whose power supply voltage and internal voltage do not exceed the safety extra-low voltage (class safety instruments), apply a 100V DC voltage between the primary circuit of the power supply and the casing. After the megohmmeter reading stabilizes at 55, the insulation resistance should be no less than 1M0. 7.3.3 Leakage current test
Regardless of whether the instrument is connected in single phase or three phase, different test circuits are used for different power distribution factors. However, the measured leakage current of the instrument shall not exceed the following specified values:
Handheld Class I safety instrument: 0.75mA;
Mobile or fixed Class 1 safety instrument: 3.5mA; Class I safety instrument: 0.25mA;
For a system composed of several unit instruments connected to each primary power supply, each unit instrument shall be tested separately. A system composed of several unit instruments connected to the same primary power supply shall be tested as a single unit instrument. The following test shall be used for qualification inspection. A calibrated leakage current measuring instrument shall be used, and a power isolation transformer shall be used for testing.
For Class 1 instruments, all accessible conductive parts shall be tested. 7.3.3.1 For single-phase instruments with a rated voltage not exceeding 250V, the single-phase instruments and instruments using direct current shall be tested according to the circuit in Figure 1 if they are Class 1 safety instruments; and according to the circuit in Figure 2 if they are Class 2 safety instruments. Instrument under test or most sensitive conductor
Isolation transformer
Protective grounding terminal
Measuring instrument
Figure 1 Leakage current test circuit of Class 1 safety instrument connected in single phase 669
Isolation transformer
GB18523—2001
Reinforced insulation
Instrument under test
Not easy to touch conductor
Basic insulation,
Double insulation
Supplementary insulation
Measuring night
Figure 2 Leakage current test circuit of Class I safety instrument connected in single phase During the test, the conversion switch and the power switch of the instrument shall be disconnected or connected in various possible combinations, and the measured value shall not exceed its specified value.
7.3.3.2 For three-phase instruments with a single-phase rated voltage not exceeding 250V and instruments to be powered by two phase lines, if they are Class 1 safety instruments, the test shall be carried out according to the circuit in Figure 3.
Tested instrument or easily touched conductor
Isolation transformer
Protective grounding terminal
Measuring instrument
Figure 3 Three-phase connected Class I safety instrument leakage current test circuit 7.3.3.3 For instruments whose power supply voltage and internal voltage do not exceed the safety extra-low v
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