Some standard content:
Alternating Current Bridge Verification Regulation
JJG441-1986
Verification Regulation of Current Converter Bridge
YeifcationRentlatirlafThe
Aiternating Currem Bridge
JJG441-186
This regulation was approved by the State [Bureau of Metrology] on May 28, 1980 and came into effect on April 1, 1917. Responsible unit: Shandong National Institute of Metrology Drafting unit: Guangdong National Institute of Metrology Technical strategy of this regulation is responsible for or interpretation of: The main drafters of this regulation are:
Ruan Yongshun (China Institute of Metrology) Institute)
Participant in the chapter:
Wang Xiaochao (China Institute of Metrology
Technical requirements
Verification policy…
【Inspection equipment·
(II) Six aspects of Tongdian
1. Verification items and verification methods
4. Verification results and idle period·
Appendix 2
Appendix?
Thank you 5…||t t||AC bridge calibration procedure
This procedure is not suitable for the calibration of AC bridges in use and after repair. It includes the actual current ratio bridge used for AC muscle, conductor, capacitor and its pseudo-torsion factor, inductance factor and its product factor: the working frequency of the bridge is limited to 40Hz and the frequency is within the range of 20kH. The calibration frequency is lower than
. This regulation is suitable for calibrating high-voltage power, high-voltage power and other special bridges. Technical requirements
1 The accuracy of the alternating current is classified as follows: 0.001.0.0m, 0.0c5.U.01.0.02.0.05.U.1.0.2, 0.5, 1.2, 5.2 The basic limit of alternating current is composed of two parts: {1) constant terms related to the calibration value;
(2) variable terms related to the self-regulation:
can be expressed by the following formula:
=-C[1- %
100x+Rg!
Wherein: grade index expressed in percentage: - allowable relative differential error;
2 allowable absolute differential error, unit: upper or E: R-standard value, unit is n, H or F, etc.: - effective indication value, unit is 1, H or F, etc.: K-- series, take 1 center (or accept the "rule of thumb", but not less), (2
For multiple frequencies and wide ranges, the grade potential of each range for the product can be listed separately or by formula, and the chart shows, 3 stable
In compliance with the provisions of the system, operation Under the conditions of compilation and initial storage, the bridge should meet the minimum error specified for its accuracy level within one year.
4 Data and markings
The bridge should provide the following data and markings on the inscription or casing, or in the documents provided by the parties: 4.1 Data
①Manufacturer's name or mark
②Mold number and serial number:
Specification, effective range, measurement factor (multiplier):
Accuracy level of the electric correction disk:
The phenomenon during random inspection and allowable error: You can use the nominal value for normal work: Shan Guang industry manual;
New certificate of use.
4.2 Marking
The marking shall be clean and not easy to wear out. The mark shall be fixed to the standard of 4.2.14.1 in the case of the enterprise or the standard bridge. 4.2.2 All terminals shall be marked to indicate their kinetic energy: Three conditions
【a) Standard equipment
5 When testing, the AC bridge should have the following testing equipment
5.1 Standard capacitors, transformers and variable electrical appliances. 5.1.1 Nominal value
--F (if necessary, expand to 1F
5.1.2 Technical indicators of standard electric seals
According to the requirements of JG183-1976 standard capacitor trial source, in addition, frequency stability and academic storage data must be included. 5.2 Standard electric devices and electric seals
5.2.1 Nominal value
10-$ -- [
5.2.2 Standard indicators of inductors
According to the requirements of G18-[976 standard for the trial verification of inductors: In addition, there must be metrological factors such as frequency stability,
5.3 AC standard resistors and AC resistance boxes. There is no national standard document for AC resistors at present. Please refer to standard document 272 (1979) for the time being. 5.4 Self-capacitance consumption factor standard device, inductance quality indication standard device and resistance time band standard device. See the attached requirements!
5.5 Meters and display meters are modified according to the "allowable variation of the quantity under the specified time" requirement of the thermometer, hygrometer and barometer. The measurement error of them is less than 1/5 of the allowable variation of the interference film when detecting. 5.6 Frequency counters are used to generate AC digital barometers for frequency and voltage measurement. The accuracy shall not exceed 1/10 Basic difference of medium and low voltage: 5.7 high i
see 15 policy time.
5.8 standard win AC bearing
is determined according to the yuan. For the same equipment, the variable bridge of the same store can reach the planned quantity. The error should not be more than the value specified in Table 1 (II) when the specified environment
is tested, and the reference equipment shown in Table 2 should meet the allowable variation. 8. The timing control shall be in accordance with the operating sequence and operating state specified in the technical manual of the bridge (if necessary, the operating mode and wiring method shall be selected, etc.), otherwise the system will continue to be faulty after repair. 9. If the system does not have a timing control, the bridge shall be able to withstand exposure to the basic temperature in an environment of 2 to 15: without damage. After reaching the specified conditions, the bridge shall still meet the technical requirements of Table 1. 0.05. 3.tu2.
IS. 、2 5
.I, .0m?
Small injection quantity on the basis of the recognition of the modified inspection of the base
bridge called convenient national technical no explosion actual difference
D and the standard scene H of the six errors and the lack of inspection
connected to the health drink free road
1: D>2JC 1, O≤1C
T: When D≤2×1C 4, Q>10C
When the converter is under the given reference conditions, the variation of the following quantity (maintaining the other dry batches under reference conditions F) shall not exceed the values specified in Table 3. Table 2 Interference quantity variation and external environment variation
External environment
External environment variation ... 3. The bridge standard has a fixed light tolerance range and is not specified by the manufacturer.
Electricity conditions (%
0.201---0 002
Basic reading of the "score of the agricultural small.
You or thorn" imagine.
You like a flower picture
Test position-
Line qualification-15%
Three verification items and verification methods
Qualified AC power conditions, should complete the change 4 specified its control items specified when a state quantity allowable evaluation difference
- 15-- 5
For the change operation 5
External modification inspection
Single position
Power supply
Operation type engineer
Measurement of electrical power
Six medical
11,12. 13
2. 26, 27
Comparison: 1. + "I show that the main inspection table of the purchase is necessary to violate the decision of the material
3, the control is still, the effect of the removal of the "absolutely strict" and other electrical inspection; (i) Appearance inspection
The integrity of the bridge should be checked in accordance with the manufacturer's technical instructions: 1
The bridge should not have any defects that affect the performance (such as the original control is not good, the degree is not clear, the contact is not good, etc.): if the product is not dead, re-calibrate it.
(ii) Resulting blood efficiency
14 The test voltage is 0.75k, the frequency is 50H, and the power is not less than 0.For 25V test equipment, the test product bearing time is 21min (when the DC power supply and the ground wire are connected, first disconnect the DC power supply and connect the ground wire). (3) Determine the absolute resistance
5 Use a high resistance meter to measure the resistance. The value is 10-1, the operating voltage is 1-11, and the measurement error is less than 30%.
Correct the absolute resistance between the two and find less than 1002. (IV) Operation test
17 According to the instructions for use of the bridge, turn on the power, connect the standard equipment, tentatively pass the bridge, observe the working state of the bridge, and check whether the contact between the switch and the probe is good. In order to eliminate the large oxide film or dust on the surface caused by long-term storage, the knob should be turned back and forth a few times before turning on the connection, and then the operation test is carried out. V) Determine the sensitivity of the bridge
18 When determining the sensitivity of the bridge, it should be carried out under the rated working voltage specified in the instructions for use. Only the sensitivity during the test can be measured. When making comparative measurements, first balance the bridge, then rotate the bridge by an amount equivalent to ten percent of the correction factor to determine the corresponding deflection grid number of the indicator. The deflection grid number should not be less than [grids]. The relative sensitivity S and absolute sensitivity S of the bridge can be calculated by formula (3) or formula (4): s_
to obtain the measured parameters, and take the calibration value:
or the increase in the measured state or the increase in the bridge main adjustment disk: a—When the increase is distributed, the deflection grid number of the indicator group (3)
18.1 to 1. Use a three-machine or oscilloscope display element to adjust the minimum input value of the daily point, and the point to be measured is 491
. After the difference is introduced, it should be within the basis of the electricity price. If the "production" technical parts do not specify, then the purchaser should teach the two small bridge level or number 1/10.18.2 When the state comes to the state overall calibration method, also called after the inspection called analysis, the error is reported: small inch complete display, six determination of the speed difference
19 frequency meter determination of power supply frequency indication deviation, power supply frequency indication deviation = input power reading, should be small 1/1 bridge basic error:
20 Some AC bridges or the marking devices used are greatly affected by the time of the power supply, the state should calibrate the power supply's electrical indication difference (North) bridge indication basic error calibration, press the items in the picture to select the calibration conditions. 21. The working efficiency of the fiber timing grid
is calibrated under the calibration frequency specified by the technical conditions of the bridge. If the bridge to be tested has a short circuit, the working efficiency of the mixing bolt can be selected according to the following measuring range:
in step 1F-1,F, 10.-0.1H.-2~1U2 AC electrolysis, calibrated under 1H, 1,,>U electrolysis, calibrated under 50T or 0001: 22. The basic measurement range of the reverse control
wide range is divided into several ranges, and the technical specifications of the bridge stipulate that it must be calibrated to the accuracy of the range (sometimes there can be several basic ranges). If there is no such time limit, select the most accurate or the scale when the ratio of the proportional device is 1, or use the scale when the bridge indication is used to the maximum reading effect according to the standard scale.
23 Working voltage of the bridge
When the bridge is calibrated with a standard instrument, the selected working voltage should be in accordance with the requirements of the bridge to be tested, and the smaller value should be selected.
24 Temperature and humidity calibration time
Before the bridge is calibrated, it should be stored in the environment shown in Table 2 for a period of time to achieve stability. Due to the different structures of the bridge and the differences between indoors and outdoors, the required stability time is not required. Therefore, only empirical data is provided. The following is a standard:
0.001~0.05 level efficacy 24h
0.1-5 digital storage 8h
25 The whole calibration reaches
The whole calibration method is to use the corresponding standard device as the measurement object of the bridge under the reference condition of the bridge, so as to determine the basic error of the bridge indication.
25.1: Determine the basic error of the bridge measurement of AC resistance (1 conductor) and inductance 25.1.1 Direct calibration with standard
According to the visual inspection object, connect the corresponding standard device, adjust the standard device (using capacitor, resistance box or inductor) and the orthogonal component adjustment disk to balance the electrolyte, so as to determine the actual value or the next value of the bridge indication, and complete the digit-by-digit calibration of all digital display channels. At this time, except for the decimal point, the other decimal points are zero. 25.1.2 The user has made a special supplementary test. The resistance of the user is connected with the standard inductor (or inductor) in single connection or parallel connection. The Q value of the standard is close to the maximum value of the bridge reading device, and the Q value is close to the minimum value of the bridge reading device. The capacitance and inductance values of the standard can be selected from the supplementary value. 492
15,1.3 When the overall verification method is used, the error of the inductor reading can be calculated as follows: Absolute valuewwW.bzxz.Net
Relative error
Where X-: Bridge indication:
X—Standard nominal:
Actual value of the standard.
XB-Xsx100%
For new multi-digit 10-digit instruments, the error of each disc is better than Appendix 5.(5)
25.1.4 When the standard is connected to the standard for supplementary calibration, the difference between the two calibration results is less than the composition specified in the technical documents of the oscillator. If the micro-bridge technical document does not have a corresponding indicator, there is a corresponding correction formula. The difference between the two test results should be less than the basic setting difference of the bridge under test. 25.1.5 When judging whether a certain value is good or not, do not reduce the value (or actual value) in the verification. Except for the basic process, for the rest of the processes, only select the two indications with no error in these processes for verification, and check each section separately according to this principle. , and then record and judge that this incremental phase is qualified. 25.1.6 For the other ranges, when the bridge timing of the real ball value is also drawn, you can select three indicators in the first decimal disk, and then forget the other early range coefficients F of the proportional device, and measure the actual value of the indicator. Use our "increment ratio" to determine the actual value of the range coefficient, as shown in Liu's formula (7): Fa-
K'-Kopu-P.
k*=KaPso-Pa
Ki- (Ki+K-hT)
The actual value of the gravity system of the first particle to be determined: Ia: 1, -1, m, n and the actual value of the first plate; Pat, Po, Po
The actual value of the first 1, and the actual value of the second input: 4: (full inspection) The actual value of the range coefficient of the range is obtained by connecting the formula (? The three quantities are K, KK\, and the difference between them should be (13% (C is the difference index).
If the actual value or correction table of the indication of the remaining values of the Ryden bridge under each range is listed, the formula (8) is used to calculate: K.'a
Pe= (Pa Pm) kc
wherein P is the actual value of the indication on the first plate under the mother range; Fo is the zero value of the bridge indication under the mother range: ()
P. The equivalent value under this range:
K is the actual value of the light coefficient of the disk length: Ko is the actual value of the mother range coefficient of the stem (full inspection) range, 25.1.7 to 1 and there are multiple lower The error of indication of the bridge under test can be calculated according to formula (9):
wherein X is the indication of the bridge when the frequency is f; Xsr is the actual frequency of the standard device when the frequency is f: 8 is the indication error of the bridge under test when the frequency is f (4)
25.2 Determine the bridge loss (composition), quality factor (composition) and residual inductance (or residual inductance) of the bridge under test! The error of indication.
In the overall measurement process, select the appropriate basic technical program, determine the indication error of each decade one by one, and compare the other uncertain ones at zero.
25.3.1 In the basic range of the bridge under test, you can select any capacitor (or electric energy value) composed of a disassembly factor standard (or quality factor standard), which has a discrete nominal value combination test standard. When the bridge is balanced, the reading mechanism of the bridge must be used to measure the three indications of the two rods of the same phase. For the annual loss dial, the three indications must be measured, that is, the initial indication, the middle indication and the maximum indication of the dial. 25.2.1 For the remaining non-basic ranges, it is allowed to calibrate only the first two indications of the dial, that is, the initial, middle and maximum indications, and calculate the range coefficient (25.2,3 For the AC bridge that can distinguish the internal and external components, the corresponding standard instrument can be used to calibrate the orthogonal display error according to Article 25.1. 25.2,4. The calibration steps of AC1100 type square meter, AC1105 type inductor bridge and C302L type capacitor bridge shall be carried out according to the requirements of Appendix 2. 2% According to the component calibration method, the value of the component calibration can be independently measured by the internal calibrator and proportional meter. When the bridge line is connected to the complete seat, the value of the calibration is not measured separately. Because: the calibration of the component has a total of independent military cut-offs,
for each component, the calibration of the component shall be carried out according to the provisions of the technical documents of the structural calibration, and the shielding mode and working state shall be kept unchanged (the potential of the shielding, the load current, the terminal and the power consumption, etc.). The deviation of the working state from the specified surface causes the change of the component. The additional error introduced is not more than 1/0 of the basic error. When the component is measured alone, the change of its relative position or the influence may cause the change of the parasitic element: Therefore, it is necessary to perform a supplementary overall calibration in each monitoring process: the starting point, the middle point and the missing point of each type of measurement can be measured. The error of the indication can be measured:
According to the relevant calibration process, the various elements and components of the measured bridge can be calibrated. The allowable measurement error of each element and component can be checked according to the indicators specified in the technical documents of the bridge. When the error is specified, the calibration personnel should perform the individual error recognition according to the bridge.
After the bridge is inspected, the following order can be followed according to the provisions of Article 11 and Article 20 of the regulations to calibrate the performance of the entire component under test. After completing the three verification items mentioned above, the four connections between the instrument and the parts are opened and recorded (one is connected by a plug): so that each element and component can be measured according to the component,
26.2 Determine the in-phase component (main parameter): the temperature difference of the measured element is measured by the decimal point, and the internal stability of the component is measured by scanning the corresponding electric correction. The instrument does not want to measure the actual main parameters of the element, but also determines the residual component that is missing. The measured component is the first circuit, and the sub-current retreat rate box is accurately equipped with a two-level circuit bridge. Not only the actual values of the capacitance box and the monthly customer under each indication are measured, but also the conductance value (or the full value of the conductance loss value) is collected. The capacitance loss value of the circuit must meet the requirements of the relevant provisions in the technical system of the drum inspection bridge. 26.3 Determine the working component (residual component )! The accuracy of the residual component of the AC current measurement terminal is smaller than the accuracy of the main component of the measurement. Compared with the orthogonal component 1, the number of digits of the reading is less, and the accuracy is changed. The method of 26 and 2 is used for control. 26.4 Determine the actual effect of each component in the proportional device on the measured device. 26.5 Perform additional verification of the transmission components, check the circuit and restore the normal working state, and perform additional overall verification of each component of the bridge. 27 The half-bridge method is to use the corresponding external standard device to measure the internal standard device of the bridge and the engraving device under normal working condition of the bridge, and then combine the errors to obtain the indications of the bridge. This method is called half-bridge. Some physical determination methods. This method is more often used to verify transformer bridges, because in general, the error of the ratio of the broken comparator (the error of the value and the influence of interference are small when the internal standard is avoided. Therefore, the verification method is simplified (see Appendix 2).
27.1 Verification of internal resistance ring calibrator
When there is only one internal standard tracker in the bridge, the range coefficient is selected! Use an external standard with the same value as the measured bridge: adjust the bridge balance, and the error element of the internal standard is calculated according to formula (11): 2-Xs
Where 5 is the error of the internal standard (the relative error of the internal standard group is opposite to the error of the bridge (6)): X-the indication of the bridge:
The actual value of the external standard (the maximum value): : -1:1 ratio When the bridge has several built-in standard instruments, they should be calibrated one by one, and the other built-in standard instruments should be placed at zero or both ends at the same time: When the bridge reads "-1" and can be self-calibrated, only one built-in standard instrument should be calibrated, and the other built-in standard instruments can be calibrated one by one: one should be used as an internal multi-standard, and the process of self-calibration should be carried out according to the provisions in the bridge manual. Appendix 2. 27.2 Proportional value verification Although it has been verified that the proportional value of the inductive comparator is actually irrelevant to the user, it may be due to improper use (e.g., overheating), excessive voltage, magnetization of the core, excessive current magnetization, and excessive connection resistance of the switch, etc., which may also cause the proportional value to change. Therefore, the proportional value error should be determined according to the annual data. However, in the case of partial error, only the 1:1 and 1:1 (or 1:1 ratio) errors need to be verified. When their errors are less than the specified error, it can be used to prove that the induction ratio device is working properly. Other ratios must not be easily determined. 27.2.111 Determination of the error in the environment
Use two nominal direct current devices (or resistors) and use the transposition method to calibrate. For example, connect the external standard end and the end of the bridge to the container and the center respectively, adjust the bridge to make it balanced and write down the value, then pull, send, swap the positions, rebalance the bridge and make the value: then the error can be calculated according to formula 1): (a, e2)
D:-Ds)
are the 1:1 ratio and angle (relative error) of the proportional device respectively; 2-1)
are the second and first correction readings respectively; 3-1)
are the two values of the bridge loss constant, 27.2.21:1 (or 10:1) error determination: use two external standard droppers (preferably 100pF and 10:F type electrical appliances) with a correction value of 1:10 (or 10:1), respectively connected to the standard terminal 5 and the measured terminal X of the tested device for comparison, and the following equation can be obtained: Cx=KCs+ 4
Gx is the actual value of the electric device connected to the X end of the bridge: (the actual value of the return container connected to the S end of the bridge; - the new reading value of the bridge adjustment rate (single is the ratio value to be determined,
When (x, (and K pieces and their nominal values and corresponding relative errors are expressed, formula (12) is obtained: 0x=bx-0-RCs
Sr.1 -dx-8g -
In the formula, the relative error of the proportional value to be determined is: - when K=1, the relative error of the proportional value is %.1 - when K=0,1, that is, 1: average, the relative error of the proportional value is: x—relative adjustment error of Cx;
g—(the adjustment error of the bridge,
10——-10, that is, 10:1], the capacitance reading of the bridge adjustment disk [unit p): -.1 (1-10), the capacitance reading of the bridge adjustment disk (in F) is the required proportional value and is calculated according to formula (14): .19k3 Determine the residual component! The accuracy of the residual component of the AC measurement terminal is smaller than the accuracy of the main component. The number of digits of the orthogonal component 1 is less, and the accuracy is changed. The method of 26 and 2 is used for control. 26.4 Determine the actual effect of each component in the proportional device on the measured component. 26.5 Perform additional verification of the components. Check the circuit and restore the normal working state. Each component of the bridge is verified. 27 Half-bridge method is used. Under the normal working state of the bridge, use the corresponding external standard to measure the internal standard of the bridge and the engraving device, and then combine the errors to obtain the indications of the bridge. This is called the half-bridge method. This method is more often used to verify transformer bridges, because in general, the error of the broken comparator (the error of the value and the influence of interference when the small Ding internal standard avoids the case error. Therefore, the simplified verification method (see Appendix 2).
27.1 Internal resistance ring calibration device verification
When there is only one internal standard tracking device in the seven bridges, the range coefficient is selected! Use an external standard device with the same value as the measured Liu Xiang: adjust the bridge's selling number plate to quickly balance the bridge, and the error element of the internal standard device is calculated according to formula (11): 2-Xs| |tt||Where 5 is the relative error of the built-in standard instrument (the relative error of the built-in standard group is of opposite sign to the error of the bridge (6): X is the indication of the bridge:
Actual value of the external standard instrument (maximum value): : -1:1 ratio difference:
When the circuit has several built-in standards, they should be calibrated one by one, and the other built-in calibrators should be placed at zero or both ends at the same time:
When the bridge reads "-1" and can be self-calibrated: then only one built-in standard instrument is calibrated, and the other built-in standards can be calibrated one by one: Research and election leader As an internal test standard, according to the provisions in the bridge manual, the process of the self-converting process is Appendix 2.
27.2 Proportional value verification
Although it has been verified that the proportional value of the inductor is actually irrelevant to the input, it may be due to improper use (e.g., overheating), excessive voltage, the core resistance, magnetization of the direct current, and excessive connection resistance of the switch, etc. 5
may also cause the proportional value to change, so it is not necessary to determine the difference in the proportional value every year. However, in some cases, only the calibration is required. 1:1 and 1:1 (or 1:1 price) error: when their error is less than the allowable error, it can be used to prove that the induction ratio device is working properly. Other ratios must not be easily determined. 27.2.111 Determination of error
Use two nominal direct current devices (or resistors) and use the replacement method to calibrate. For example, connect the external standard end and the end of the bridge to the container and the center respectively, adjust the bridge to make it balanced and write down the value, then pull, send, swap some positions, rebalance the bridge and make the value: then the error section can be calculated according to formula 1): (a, e2)
D:-Ds)
are the 1:1 ratio and angle (relative error) of the proportional device respectively; 2-1)
are the second and first correction readings respectively; 3-1)
are the two values of the bridge loss constant, 27.2.21:1 (or 10:1) error determination: use two external standard droppers (preferably 100pF and 10:F type electrical appliances) with a correction value of 1:10 (or 10:1), respectively connected to the standard terminal 5 and the measured terminal X of the tested device for comparison, and the following equation can be obtained: Cx=KCs+ 4
Gx is the actual value of the electric device connected to the X end of the bridge: (the actual value of the return container connected to the S end of the bridge; - the new reading value of the bridge adjustment rate (single is the ratio value to be determined,
When (x, (and K pieces and their nominal values and corresponding relative errors are expressed, formula (12) is obtained: 0x=bx-0-RCs
Sr.1 -dx-8g -
In the formula, the relative error of the proportional value to be determined is: - when K=1, the relative error of the proportional value is %.1 - when K=0,1, that is, 1: average, the relative error of the proportional value is: x—relative adjustment error of Cx;
g—(the adjustment error of the bridge,
10——-10, that is, 10:1], the capacitance reading of the bridge adjustment disk [unit p): -.1 (1-10), the capacitance reading of the bridge adjustment disk (in F) is the required proportional value and is calculated according to formula (14): .19k3 Determine the residual component! The accuracy of the residual component of the AC measurement terminal is smaller than the accuracy of the main component. The number of digits of the orthogonal component 1 is less, and the accuracy is changed. The method of 26 and 2 is used for control. 26.4 Determine the actual effect of each component in the proportional device on the measured component. 26.5 Perform additional verification of the components. Check the circuit and restore the normal working state. Each component of the bridge is verified. 27 Half-bridge method is used. Under the normal working state of the bridge, use the corresponding external standard to measure the internal standard of the bridge and the engraving device, and then combine the errors to obtain the indications of the bridge. This is called the half-bridge method. This method is more often used to verify transformer bridges, because in general, the error of the broken comparator (the error of the value and the influence of interference when the small Ding internal standard avoids the case error. Therefore, the simplified verification method (see Appendix 2).
27.1 Internal resistance ring calibration device verification
When there is only one internal standard tracking device in the seven bridges, the range coefficient is selected! Use an external standard device with the same value as the measured Liu Xiang: adjust the bridge's selling number plate to quickly balance the bridge, and the error element of the internal standard device is calculated according to formula (11): 2-Xs| |tt||Where 5 is the relative error of the built-in standard instrument (the relative error of the built-in standard group is of opposite sign to the error of the bridge (6): X is the indication of the bridge:
Actual value of the external standard instrument (maximum value): : -1:1 ratio difference:
When the circuit has several built-in standards, they should be calibrated one by one, and the other built-in calibrators should be placed at zero or both ends at the same time:
When the bridge reads "-1" and can be self-calibrated: then only one built-in standard instrument is calibrated, and the other built-in standards can be calibrated one by one: Research and election leader As an internal test standard, according to the provisions in the bridge manual, the process of the self-converting process is Appendix 2.
27.2 Proportional value verification
Although it has been verified that the proportional value of the inductor is actually irrelevant to the input, it may be due to improper use (e.g., overheating), excessive voltage, the core resistance, magnetization of the direct current, and excessive connection resistance of the switch, etc. 5
may also cause the proportional value to change, so it is not necessary to determine the difference in the proportional value every year. However, in some cases, only the calibration is required. 1:1 and 1:1 (or 1:1 price) error: when their error is less than the allowable error, it can be used to prove that the induction ratio device is working properly. Other ratios must not be easily determined. 27.2.111 Determination of error
Use two nominal direct current devices (or resistors) and use the replacement method to calibrate. For example, connect the external standard end and the end of the bridge to the container and the center respectively, adjust the bridge to make it balanced and write down the value, then pull, send, swap some positions, rebalance the bridge and make the value: then the error section can be calculated according to formula 1): (a, e2)
D:-Ds)
are the 1:1 ratio and angle (relative error) of the proportional device respectively; 2-1)
are the second and first correction readings respectively; 3-1)
are the two values of the bridge loss constant, 27.2.21:1 (or 10:1) error determination: use two external standard droppers (preferably 100pF and 10:F type electrical appliances) with a correction value of 1:10 (or 10:1), respectively connected to the standard terminal 5 and the measured terminal X of the tested device for comparison, and the following equation can be obtained: Cx=KCs+ 4
Gx is the actual value of the electric device connected to the X end of the bridge: (the actual value of the return container connected to the S end of the bridge; - the new reading value of the bridge adjustment rate (single is the ratio value to be determined,
When (x, (and K pieces and their nominal values and corresponding relative errors are expressed, formula (12) is obtained: 0x=bx-0-RCs
Sr.1 -dx-8g -
In the formula, the relative error of the proportional value to be determined is: - when K=1, the relative error of the proportional value is %.1 - when K=0,1, that is, 1: average, the relative error of the proportional value is: x—relative adjustment error of Cx;
g—(the adjustment error of the bridge,
10——-10, that is, 10:1], the capacitance reading of the bridge adjustment disk [unit p): -.1 (1-10), the capacitance reading of the bridge adjustment disk (in F) is the required proportional value and is calculated according to formula (14): .19k
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