JJG 874-1994 Temperature Indicating Controller JJG874-1994 Standard Download Decompression Password: www.bzxz.net

Verification regulations for temperature indicating controllers
JJG874—1994
Verification regulations for temperature indicating controllers
Temperalurelndicatlon Conlruller .
JJG8741994
This verification procedure was approved by the State Technical Supervision Administration on April 5, 1994, and was implemented from December 1994 onwards. The responsible unit is: 1. Haishan Technical Supervision Bureau
Drafting unit: Tianjin Metrology Research Institute
Drafting unit: Tianjin Metrology Research Institute
Drafting unit: Tianjin Metrology Research Institute
Drafting unit: Tianjin Metrology Research Institute
Drafting unit: Tianjin Metrology Research Institute
Drafting unit: Tianjin Metrology Research Institute
Drafting unit: Tianjin Metrology Research Institute
Drafting unit: Tianjin Metrology Research Institute
Drafting unit: Tianjin Metrology Research Institute
Verification items and determination methods
5. Requirement and determination cycle of verification results
Appendix! Temperature indicating controller inspection record format Temperature indicating controller verification certificate (back) Appendix 2
Verification procedures for temperature indicating controllerbzxz.net
This procedure is applicable to newly manufactured, used and unrepaired measuring instruments, using thermal resistors, other semiconductor-type temperature control devices and salinity control instruments (in short, all instruments are replaced with temperature control instruments). The temperature control system is composed of a temperature measuring circuit, a comparison circuit and a relatively high Signal type, position temperature control circuit, electronic components: measuring system, temperature sensing device can change with temperature, through the right middle circuit, the temperature displayed on the meter is required to be displayed in the state, and the method to measure the temperature is as follows: 2. Technical requirements
1.1 The temperature control component is marked with the product name, model, standard, manufacturer name, number, date of display! The temperature symbol and "H" mark and the separation are in accordance with the regulations. 1.2 The packaging materials used for the temperature control instrument should be replaced regularly, the connectors should be good, the connections should be firm, the light should be good, and the temperature sensing material should be able to withstand the intended use temperature according to the same maintenance provisions. 1.3 The temperature control instrument should be able to normally indicate the starting point of the instrument, etc. The lake account indicates the starting point of the meter, and the indication represents the horizontal movement of the meter, the abnormality of the meter data and the delay of the meter.
1.4 The control instrument should only indicate the meter within 1/4·3/4 of the short solid line: the width of the pointer tip should be greater than the vertical scale of the main scale:
1.5 The setting knob mark of the controller. It can be set on the scale and is more complete: 2 Indication allowable error
The control value should not be allowed to have an error greater than the provisions of the table [(when the table lists the error: the stop pointer shall prevail), 1
Indication allowable limit
Setting point setting ticket
- 50 - - 5)
Control only the set point error to allow a course ticket, + switch recommended
50 --200
100 300
20- 34G
The switching difference of the controller is less than the upper limit temperature or 1 plus 0, the error is not greater than the indicated value. The upper limit benefit is 10. The virtual value is not more than 10. The indicated value is allowed to be used. The absolute difference is 1A:5. The ambient temperature is one, and the humidity is not greater than that of other goods. The control power supply circuit and the charging text are not less than 2M
6 The insulation degree is 5-35, and the relative sensitivity is not greater than 8%. The controller circuit can be applied with 116+
5V AC, and the temperature is 1-m degrees to produce overcurrent and flying alarm phenomena. Three verification conditions: standard mercury thermometer 0-:kr):
8 Qualified equipment
8.1 The requirements of the technical requirements of the control instrument and its technical requirements are in accordance with Table 2: Table 2
Reading telescope and six-point
Freezing point instrument.
Digital insulation resistance meter
Output voltage is not less than 1500V, output cut-off rate is 0,25kW withstand voltage test, with leakage current setting position, current setting is 5.
Fourth verification items and verification methods
Controller internal inspection items
New manufacturing and repaired control items are 1-6, and the in-use inspection items are 1-4. External specifications inspection
Use H as the current, and meet the requirements of the first "kill". 11.1 Verification points: The calibration points of the cow milking machine should be evenly distributed on the indicating scale within the measuring range (including the upper and lower limits of the measuring mouse), and there should be no less than 5 calibration points. 11.2 Implementation order: Generally, the lower limit temperature point should be measured at the upper temperature point, and the negative temperature zone should be measured at the lower points. 11.3 Reading method: Before reading, first calibrate the starting point of the effective scale, and lower your sight from the dial. The reading should be estimated to be at least 1/10. Use a magnifying glass to read the reading. The center of the effective scale should be passed through. 11.4 Zero point verification: The temperature controller should be equipped with an ice-proof device, The freezing point of the water mixture, the second is also the freezing point of the bottom, the wall shall not be less than 2Umm, read the minimum value after it stabilizes, the reading shall not be less than 2 times, 11.5 Verification of other points: Verification shall be carried out by comparison method: 11.5.1 The temperature of the position shall not exceed 0.2t from the specified verification point (with the standard thermometer as the full value) after the temperature field is stabilized, and then calibrate. During the calibration process of each point, the temperature change shall not exceed 0.10 (using the automatic control resistance and temperature control H, the control value shall not exceed 0.05t:/10 yuan in) 1.5.2 The actual accuracy and indication error shall be calculated according to formula (1) and formula (2): -A+
武中．
Constant temperature value;
A—standard temperature value,
correct value of the calibration point, t
or: the indication error of the calibration correction.
.—indication of the control instrument, the indication error of each point of the control instrument shall comply with the provisions of Article 2, 12. Verification of fixed point difference and switching difference
12.1 Verification point: Carry out on the scale limit of the calibration, the machine should set three cards 12.2 Calibration method: Align the control signal setting mark with the desired temperature point, insert the temperature gauge and the sensor of the control instrument under test into the constant temperature plate, and then slowly increase the constant temperature. When the output signal is switched, read the indication of the temperature gauge, and the temperature value is the upper switching value. The more the constant temperature is slowly reduced, the more the output signal is on time. Take the indicated value of the standard temperature certificate, the standard temperature value is the lower switching pin, the temperature is the temperature drop rate of the sugar at the specified time: 1.1t:m-): This is the reverse effect 12.3 Set point error: 2 times the average value of the switching value of the switching source and the average value of the lower switching value of the rolling point temperature is the set point error. The value should comply with the provisions of the 3rd system. 12.4 Special switching error: The average value of the upper initial switching value and the half-mean difference of the lower switching value temperature is the switching error. But it complies with the provisions of Article 4.
13 Insulation
Connect the two leads of the insulation resistance meter with a DC voltage of 500V between the controller circuit and the shell, measure the insulation resistance, and keep it for 10s. The reading is effective. The insulation resistance is in accordance with the provisions of Article 5: 14 Insulation Width
Connect the two terminals of the high-voltage tester between the power circuit and the shell of the controller, and apply 150V AC voltage. The voltage is zero and stable.Rise to the specified value; ensure that there is no blue penetration and 5 chaos or leakage current alarm for 1m: then the average value drops to the level to cut off the source.
After the pressure test, the control is still working normally and meets the requirements of each test. 5. Processing of verification results and verification period
15. The verification certificate will be issued to the control instrument that meets the requirements of this regulation. If it is unqualified, a notice of completion will be issued, and the verification period will be calculated.
16. The verification period of the control instrument can be determined according to the user. The average position difference is shown in the following table. The setting point is monitored in depth. The control element is calculated based on the standard. Model
Quickly come out
Qualification staff
Thank you record 1
Temperature indicating controller calibration record style
One change
Down the basket
Half power
Compared with the fixed point source difference
Limited
Thank you record 2
Small position method
Set point promoter
Sweep the section
Source seat
Model view
Dangerous station theory
Quantity R period:
Measurement indicating control instrument inspection shop certificate check surface precision grain determination result
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