Some standard content:
1 Scope
National Standard of the People's Republic of China
DC bridge for measuring resistance
DC bridge for measuring resistance This standard applies to point-to-point current bridges used for measuring resistance, and also to the auxiliary equipment attached to the bridge. UDC 621.317.733
011.22: 621
317.331.083.4
GB 3930—83
IEC564--77
This standard does not apply to bridge comparators, automatic balancing bridges and bridges that replace the null scale to obtain partial indications, and is not suitable for external auxiliary equipment used with the bridge (Note: A bridge comparator is a device used to compare two resistors, such as an adjustable ratio set with two arms).
2 Terms and Definitions
2.1 DC bridge for measuring resistance (hereinafter referred to as "bridge") A combination of at least two resistor arms, plus a test resistor, forms a bridge network. When the bridge is in operation, a DC power supply and a zero indicator are also required. These can be included or not included. When the bridge is balanced, there is a calculable relationship between the resistance values of the resistors.
Previous: The DC bridge for measuring sensitive resistors can be used to browse two-terminal or four-terminal resistors with or without leakage current shielding (circuit), and accordingly control it as a two-terminal bridge or four-terminal resistor with or without leakage current shielding (circuit). 2.2 Test resistor testresistor
Resistors to be measured
2.3Two-terminal resistorTwo-terminal resistorA resistor with only one current and potential terminal at each end. 2.4Four-terminal resistorFour-terminal resistorA resistor with two terminals at each end, one of which is used to connect to the current-carrying loop and the other is used to connect to the potential measurement circuit. Note: Assuming that no current flows out of the potential terminal, the resistance value is defined as the ratio of the potential difference between the two potentials to the current flowing through the current terminal. 2.5Resistors with leakage current screen (circuit)Resistors with leakage current screen (circuit) connected to the isolation terminal (usually called the "guard terminal"). Note: The resistor with leakage current screen (circuit) can be represented by a network composed of three equivalent resistors connected to each pair of terminals. The resistance between the two main terminals of the three resistors is the equivalent resistor to be measured. The two resistors in the diagram are usually the leakage resistors, which are equivalent resistors of very high resistance values. Their resistance values are coded: the equivalent resistance is one level or lower than the equivalent resistance. The equivalent resistor can be regarded as a two-terminal resistor, or a standard resistor. 2.6 decade resistor resistance decade-a multi-value resistor that can select the combination of resistors in equal steps, usually by means of a switching device. Each step value is equivalent to an increment of the decade resistance, for example 0.1%, 1 or 102. Note: A switch can select 10, 11 or 12 resistance values (including zero) 2.7 range-changing device range-changing device A switch or similar device that multiplies the effective range by a factor called "range factor" or "range multiplier" (for example: 0.1).
2.8 Measuring dials
National Bureau of Standards 1983-11-08 Issued
1984-06-01 Implementation
GB 3930 —83
Reading dials for determining the resistance of the test resistor. If a range converter is integrated, the setting of the converter should also be considered. 2.9 Connecting resistance (potential) tonnating resistance (potential) For a four-terminal bridge, this is the resistance of the wire connecting the potential end of the bridge to the corresponding potential end of the test resistor, plus the resistance of the potential wire inside the test resistor.
2.10 Link resistance (current) For a western bridge, this is the resistance of the wire connecting the current end of the bridge to the corresponding current end of the test resistor, plus the resistance of the current wire inside the test resistor.
2.11 Auxiliary equipment Auxiliary equipment necessary to enable the bridge to operate accurately and safely as specified. It may or may not be an integral part of the bridge. 2.12 Ripple content Ripple content RMS value of the ripple component
Average value of the power supply
2.13 Leakage current screen (circuit) Leakage current screen (circuit) Conductive passage to prevent leakage current from affecting the test results. The terminal strip of the leakage current screen (circuit) is called the "protective terminal". 2.14 Electrostatic screen - A conductive shell or coating used to protect the space it surrounds from the influence of external static electricity. 2.15 Measuring terminal measuring termina
Terminal used to connect the test resistor. 2.16 Measuring circuit measuring circuit Internal circuit of the bridge that is (or can be) conductively connected to the measuring terminal. 2.t7 effective range
the range of resistance values between the lowest and highest resistance values that the bridge can measure with a specified accuracy for a given range factor. 2.18 overall effective range the total range of resistance values that can be measured with a specified accuracy using all range factors 2.19 dial setting
the number of measuring dials after the bridge has been balanced. When determining the value of the test resistor, multiply by the range factor, if applicable. 2.20 resolution
for measuring dials with only discontinuous readings, the resolution is the resistance value corresponding to one step of the lowest value measuring dial on any given range. For bridges with one of the measuring dials being continuously adjustable, the resolution is the resistance value corresponding to the smallest division within any range of the lowest value measuring dial settings on any given range. Note: in the case of continuously adjustable non-linear measuring dials, the resolution may vary with the number of measuring dial settings. 2.21 influence quantity
a quantity other than the measured quantity that tends to cause an undesired change in the dial indication. 2.22 reference condition reference condition some specified condition under which the bridge meets the requirements for the basic error. 2.23 reference value reference value
a specified single value of an influence quantity, within whose given tolerance the bridge meets the requirements for the basic error. 2.24 reference range relerence range
a specified range of values of an influence quantity, within which the bridge meets the requirements for the Bi-value error. 2.25 variation with influence quantity the difference between the dial indications measured twice for a fixed value test resistor when an influence quantity takes two different specified values in succession. lnominalrangeofuse
2.26 Nominal range of use
The specified range of values for each influencing factor when the variation does not exceed the specified limit value: GB 3930-83
2.27 Limiting values of influencing quantity The maximum value that a certain influencing quantity can take without damaging the bridge or causing permanent changes so that it no longer meets the accuracy grade requirements. 2.28 Reference value
A single value for reference of each effective range in order to specify the accuracy of the bridge: Unless otherwise specified by the manufacturing unit, the reference value of a given effective range is the largest integer power of 10 within the range. 2.29 Error error
The value obtained by subtracting the true value of the measured value from the indication of the dial. Note: ①Since the true value cannot be determined from the measured product, the value obtained under the specified test conditions and within the specified time is used to represent the true value. This value is transferred from the national measurement standard to a standard agreed upon by the manufacturer and the account. ②The error caused by any auxiliary device not attached to the bridge is not included in the electric correction error. 2.30 Basic error intrinsic error
The error determined under reference conditions.
2.31 Accuracy accuracy
The accuracy of the bridge is determined according to the basic error limit and the variation limit caused by the influence. 2.32 Accuracy class accuracy class
The class of the bridge. All bridges that meet all the requirements of this standard can use the same number to indicate their accuracy. 2.33 Class index class index
A number indicating the accuracy class.
3 Classification
The bridges described in this standard may be classified as follows: 3.1 According to whether the bridge measures the resistance of a two-terminal resistor or a concave-terminal resistor with or without a leakage current shield (circuit).
Note: Some bridges may be capable of measuring the values of multiple types of resistors. 3.2
According to the classification of bridge accuracy grades defined in Article 2.32, see Table 1: Table 1
1 ×10 -5
2000ppm
2 × 10 3
2 × 10 -5
500Dppm
5 × 103
5 × 10-5
10000ppm
1 × 10-2
100ppm
1 × 10 -4
20000Ppm
2 × 10 -2
2 × -4
50000mpm
s × in-3
5×10-1
no0oop
10×0-2
t00oppm
1×10-3
The grade index of the bridge can be expressed as a fraction, and/or as b, in ppm, or in scientific notation. If a bridge has several measurement ranges, each range can have its own grade index. Note: Except for measuring very high resistance bridges, the accuracy grade index 2~tu (20000ppm~100000ppm) (2x10**~10×102) is not used. Explanation for use:
, compared with IEC564-77<Single DC bridge for electric power) adds scientific notation. ·*The original text of IF.C564413.2 is: "The grade index of the bridge can be expressed as a fraction, or as a part per million (ppm), or both."
4 Stability
GB 3930-83
If the conditions of use, transportation and storage specified by the manufacturer are observed, the bridge shall meet the limits of the relevant basic errors specified for the respective accuracy grades within one year from the date of verification at the time of delivery or another date agreed upon by the manufacturer (or the responsible supplier) and the user.
: For the bridge, the stability over time is a basic function. Here it is specified as one year, but experience shows that the rate of change caused by aging usually decreases with time.
5 Allowable limit of basic error
The allowable limit of the basic error of the bridge consists of two parts: a. Constant term related to the reference value:
b. 5.1 The positive and negative values of the following two formulas give the two limit values of error: RN
Elim=±
Wu: E1m—allowable error limit, α; RN—reference value, 2
z—dial indication, S2:
—grade index expressed as a percentage; K=10 (if the manufacturer does not specify a higher value). When the grade index c is expressed in parts per million (ppm), the following formula should be used: Elim = +
1000000K
When the grade index c is expressed in scientific notation, the following formula should be used: Eim = ±c(
Note: Any error caused by the lack of resolution is included in the allowable error. (1)
5.2 The bridge used to measure the resistance of four-terminal resistors shall comply with the requirements of Clause 5.1. If, in order to meet these requirements, the connecting resistance (potential end) and the cross-line resistance (current end) must have a specified value or range of values, the manufacturer shall make appropriate explanations for these values for each valid range.
6 Conditions for determining the basic error
6.1 The reference values related to the various influencing quantities are shown in Table 2 . 6.2 Before any low-frequency measurement is made, sufficient time should be allowed for the bridge to reach a stable state and for the bridge to be balanced at the reference value of the influencing quantity.
6,3 If there is a leakage current shield (line) and an electrostatic shield, they should be connected in accordance with the instructions of the manufacturer. 6.4 The tests should be carried out successively under two conditions of DC power supply. If the difference between the two measurement results does not exceed 20% of the grade index, this difference is considered to be negligible. When the difference exceeds this value, the error is taken as the average position of the errors obtained under positive and negative polarity,
Method: The test resistor should not be a source of electromotive force, otherwise, if it is a source of electromotive force, it should be taken into account when determining the bridge error. Instructions for use: || tt||1EC564 does not have this table, and it is increased by referring to IEC523-75 (79) (DC potentiometer). Influence quantity
Lake surrounding temperature
Recruitment on humidity
Bridge power supply electric shop
or current
Bridge power supply points
Standard power supply cold
Continuous with time
Reference conditions
405-60 Road
Rated value
Note: T. Unless otherwise specified by the manufacturer. ② There shall be no tolerance for the reference standard,
GB3930-83
Reference conditions and difference of influence quantity
0.00[-0.[002
0. 005~ n.05
?·If another degree is to be specified, it should be based on 23℃ or 27℃1Permissible variation
7.1 Limits of variation
50-5en
I -- n
Scientific notation
1×1052×105
5×1155-5 ×20 -4
×10-3 - 10 × i( 2
Tolerance chart for test day
When the bridge is under the reference conditions given in Table 2 and the single influence mask is varied as required in Clause 7.2, the variation shall not exceed the value specified in Table 31.
7. 2 Conditions for determining the variation
The variation shall be determined for each influencing quantity. During each test, all other influencing quantities shall be kept at their reference conditions. The evaluation variation is as follows:
a, when a reference value is specified for the bridge, the influence quantity shall vary between this value and any value at the limit of the nominal use range given in Table 3.
b, when a reference range and a nominal use range are specified for the bridge, the influence quantity may vary between each reference range limit and any value within the adjacent nominal use range. Quick Note:
* Scientific notation is added to the IEC564 spectrum
* The original text of IEC564 is: "If a temperature is specified, it shall be 23 °C or 27 °C according to IEC SU publication (Standard atmospheric conditions for the test date).
Influence island
Ambient temperature
Relative humidity
Bridge power supply
Voltage or current
0.001 -0,002
0, 005 ~ 0. 05
GB393083
Table 3 Nominal use range limits and allowable variations
To: Unless otherwise specified by the manufacturer.
50-500
1000-100000
Expressed as a percentage of the allowable basic error.
Additional electrical and mechanical requirements
8.1**: Voltage test
Scientific notation*
1 × 10-5 - 2 × 10-5
[5×10-5~5×10
1×10-3~10xIn-2
Nominal use range
Range limit
Parameter value±2℃
Reference value５℃
Reference value=10℃:
25% and 75%
Rated value
Allowed variation
The test voltage of the bridge is a function of its line insulation voltage. The table lists the test voltage values corresponding to each line insulation voltage. Table 4 Insulation voltage and test voltage of circuits
Insulation voltage of bridge circuits
Insulation resistance
Test voltage (RMS value)
The manufacturer shall specify the insulation voltage of any easily accessible terminal of the bridge circuit and other untouched terminals under the test voltage of 500V±10%. Notes:
*Scientific symbols are added compared with IEC5B4.
**Clause 3.1 Voltage test and other safety requirements in IEC564, the original text is: "The requirements for voltage test and other safety aspects are included in the IEC414 publication: <Safety requirements for electrical measuring, indicating and recording instruments and their accessories> for reference". The following table is taken from IEC 414 "Nominal line voltage (line insulation voltage) mark and test voltage of the test panel circuit. GB3930-83
Calculate and bridge the lowest DC insulation resistance value measured between any accessible points of the circuit. This value should not be less than 5MS2*. The insulation resistance measurement should be carried out between 1 minute and 2 minutes of applying the test voltage. 8.2.1 Except for the cases pointed out in 8.2.2, the variation caused by the connection of any terminal to the shell or the earth should not exceed 10% of the allowable limit of basic error. When conducting this test, if the shell is conductive, it should be grounded. If the shell is made of insulating material, the bridge should be placed on a conductive plate, and the plate should be grounded. 8.2.2 If there are restrictions on grounding, the manufacturer should indicate which terminals can be grounded or connected to the shell, or which terminals must be grounded or connected to the shell, and which terminals are connected to the outside by the manufacturer. 8.2.3 If the test resistance If the shield of the test device is connected to the leakage current shield (line) of the bridge to avoid leakage current of the test device, the manufacturer shall state the minimum leakage resistance value that will cause a variation of less than 10% of the permissible limit of error. Under such conditions, the requirements of 8.2.1 are generally no longer applicable.
8.3 Duration of application of the limiting values of the influencing quantity
If the limiting values of the influencing quantity are dependent on the duration of application, the manufacturer shall state this fact and the duration for which the influencing quantity is permitted to be applied.
B.4 Storage, transportation and use temperature limits If the manufacturer has not otherwise specified, the bridge shall be able to withstand exposure to ambient temperatures of -10 to +50°C without damage. After returning to the reference conditions, the bridge shall meet the requirements of this standard. NOTE: (If the bridge is installed on a rack test bench, ensure that the ventilation required for the operation of the bridge is not obstructed. The bridge should be transported and mounted in accordance with the manufacturer's instructions and ensure that it is properly installed. Avoid shock, continuous plate movement and temperature fluctuations within the research range to prevent changes in electrical performance.
9 Information, signs and symbols
9.1 Information
9.1.1 The manufacturer shall provide the following information:
a. The name and trademark of the manufacturer and the supplier responsible for the product b.
The model set by the manufacturer (if any): c. The serial number;
d. The effective range, resolution and range factor, for For bridges with a grade of 0.5 to 10 [(5000 to 100000 ppm) (5×10-310×10-2)], the manufacturer may also give only the total effective range instead of the former; the accuracy grade of each range or (when the total effective range is given) only the accuracy grade: e.
other K values when K value is not 10 (see 5.1) reference values and nominal use ranges of temperature, if they are different from those listed in Tables 2 and 3 Reference position and nominal range of use of the position (if necessary); i. Reference value (range) and nominal range of use of other influencing quantities (see and h times), if different from those given in Tables 2 and 3: Duration of application of the limit value of the influencing quantity (if necessary) (see 8.3) k. Main performance of auxiliary equipment (if necessary); Test voltage: Temperature limits for transportation, storage and use and other requirements (if necessary) (see 8.4); n. Circuit diagram, component values and list of replaceable parts: o. Steps for using the bridge, Instructions for use: The original text of 8.2 in EC564 is: "This value should not be less than the value specified by IEC411 Publication - Safety Requirements". This value is specified in 6.6 of EC411 as not less than 5M2.
GB 393083
Resistance or positive value range of the terminal connection resistor and the current terminal cross-line resistor (see 5.2); P.
9, resistance of DC insulation resistance (see 8.2). 9.1.2 If a verification certificate is provided in accordance with the agreement between the manufacturer or the responsible supplier and the user, the verification certificate shall contain the following:
Verification value and its uncertainty:
Verification month and date:
Name of the verification unit.
9.2 Marks, symbols and their positions
Marks and symbols shall be clear and easy to read and not easy to erase. When necessary, the symbols specified in Table 4 shall be used. 9.2.1 The following information shall be marked on the nameplate or housing: ab, ce (using symbols E-7 or F-8), h (using symbols D-1 to D-6), 1 (using symbols C1 to C-3) in 9.1.1.
In addition, the following mark shall be made: "DC resistance bridge" or this name written in another language. When necessary, the symbol F-33 indicates that other necessary information is also given in a separate document. If the reference value or reference range is marked, it shall be underlined for easy identification. 9.2.2 All terminals shall be marked to indicate polarity (when required), function and power supply, etc. In particular, the following terminals shall be marked near them for easy identification.
Measurement terminal
b, terminal for connecting auxiliary equipment;
c. : Ground terminal, if any (indicated by symbol F-31); d.
Leakage current shield (line) terminal, if any; electrostatic shield terminal, if any.
9.2.3 The following shall be given on the nameplate1 or on the housing or in a separate document: d, g, i in 9.1.1.
9.3 Provision of documents
9.3.1 The documents provided shall state:
a, a, b, c, f, k, m, n, o, P, qsb in 9.1.1, d, g, 1 in 9.1.1 (if these are not indicated on the nameplate or on the housing) (see 9.2.3). 9.3.2 The verification certificate mentioned in 9.1.2 (when provided to the user) shall state: a, b, c in 9.1.2. 9.4 Examples of bridge markings
9.4.1 Electrolysis described according to effective rangeNN
Number: 12345
(....t00kg/10)(*)
DC resistance bridge. Electric car
Model: A, B, C, D
In this example, these markings indicate:
DC resistance bridge, model ABCD, number 12315, manufacturing unit N, N., a
GB3930-83
The effective range when using ×1 maximum range coefficient is 0~100k, resolution 1, range coefficient is 0.1, ×1, ×10 and b
×100 The corresponding grade index is 50ppm, 50ppm, 10ppm, 200ppm; c. The reference value of temperature is 23℃, and the nominal use range is 20～28℃ (because these data are different from those given in Table 2 and Table 3, 3 should be marked.
d. Test voltage 2kv
No position symbol means that the bridge can be used in any position. e.
9.4.2 Describe the comb according to the total effective range NN
No. 67 8 9 0
In this example, these symbols indicate:
DC resistance bridge
Model: E, F, G, H
a. DC resistance bridge, model EFGH, No. 67890 manufacturing unit NN: b, the total effective range is 0～10M9, and the resolution limit is less than the allowable limit of the basic error. The range multiplier is ×0.! , ×1, ×10, ×100, the grade index of each range is 0.5,: When using the bridge, the support surface is vertical:
Test voltage is 500V.
Table 5 Symbols used to mark the bridge
Test voltage
Test voltage is greater than 500V (for example, 2V)
Instruments that have not been subjected to voltage tests
Usage position
Support surface vertical 1 Use bridge
Use bridge when the support surface is in water
D— 4
Instructions for use:
GBa930—83
Continued Table 5
When using the bridge, the support surface is inclined with the horizontal plane (for example, 60°) The bridge is used according to D-1, and the nominal use range is: 80 ~ + 100°
Example of using the bridge according to the D"3, nominal use range: 45～75
Grade of accuracy
When the allowable error is partly proportional to the reference value or ratio and partly proportional to the dial reading, the error grade index is expressed in percentage (e.g. 0.01)
When the allowable error is partly proportional to the reference value and partly proportional to the dial reading, the error grade index is expressed in parts per million
(e.g. loopp)
When the allowable error is partly proportional to the reference value and partly proportional to the dial reading, the error grade index is expressed in scientific notation (e.g. 1×10-1)General symbol
Electrostatic shielding
*IEC564 does not have E-9 Added due to the adoption of scientific notation. Symbols
45.-60...75
F—41
Additional notes:
Earth terminal
See separate text
Current surge protection
GB3930—83
Continued Table 5
(Under consideration)www.bzxz.net
This standard is equivalent to the publication of the International Electrotechnical Commission IEC564—77 "Direct current bridge for measuring resistance", with only editorial changes. This standard was proposed and managed by the Shanghai Instrument and Meter Research Institute of the Ministry of Machinery Industry. This standard was drafted by the Shanghai Instrument and Meter Research Institute of the Ministry of Machinery Industry. This standard was entrusted to the Shanghai Instrument and Meter Research Institute of the Ministry of Machinery Industry for interpretation. From the date of implementation of this standard, the original Ministry standard JB1391-74 "Technical conditions for direct current bridge for measurement" will be invalidated.
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