LS/T 1813-2017Grain and oil storage. Monitoring and control system of stored-grain condition technical requirements for digital measuring temperature cable (English PDF)

4.1 General technical requirements

Digital temperature measurement cables should meet the following requirements.

---Insulation and sheath should be complete and continuous without defects;

---The surface is smooth and even, the thickness is uniform;

---The sensor parts are welded firmly and the suspension components are strong and durable;

--- Both ends of the cable and the lead connection should be sealed to resist corrosion of PH3 gas;

--- Cable should be added with steel wire (or wire rope) to increase its overall tensile strength;

--- Electrical performance is stable, in accordance with the relevant provisions of GB/T 11463;

--- Low temperature resistance, in accordance with the relevant provisions of GB/T 2423.1;

--- High temperature aging resistance, in accordance with the relevant provisions of GB/T 2423.2.

4.2 Dimensional requirements

4.2.1 Outline dimensions of digital temperature measuring cable for flat warehouse

4.2.1.1 Round, diameter phi >= 8.0mm.

4.2.1.2 Flat shape, width >= 9.0mm, thickness >= 3.0mm.

4.2.2 Dimensional requirements for digital temperature measuring cables for shallow round silos and vertical silos

4.2.2.1 The height of the grain stack is <=15m, and the cross-section shape of the cable is elliptical, flat, width >=20mm, thickness >=15mm.

4.2.2.2 15m< stack height <=25m, cable cross-section shape is elliptical, width >=25mm, thickness >=15.5mm.

4.2.2.3 25m< stack height <=30m, cable cross-section shape is elliptical, width >=27mm, thickness >=16mm.

4.2.2.4 30m< stack height <=45m, cable cross-section shape is elliptical, width >=30mm, thickness >=16.5mm.

4.2.2.5 The height of the grain is >=45m, the cross-section of the cable is elliptical, the width is >=32mm, and the thickness is >=17mm.

4.3 Sheath technical requirements

4.3.1 Production process requirements

The jacket production process requires extrusion molding.

4.3.2 Material Requirements

The sheath material is as follows.

--- The digital temperature measuring cable sheath used in the flat warehouse should be made of high-pressure polyethylene material, and the finished grain should be food grade high-pressure polyethylene;

---The digital temperature measuring cable sheath used in the shallow round silo and the vertical silo is made of high pressure polyethylene or nylon material;

--- The sheath of the interconnect is made of high pressure polyethylene;

--- The digital temperature measuring cable sheath used in the oil tank is made of food grade high pressure polyethylene.

4.4 Wire Technical Requirements

4.4.1 Technical requirements for circular digital temperature measuring cable conductors

4.4.1.1 Core color requirements

4.4.1.1.1 The color of the tinned copper wire sheath shall comply with the provisions of GB/T 6995.1.

4.4.1.1.2 Two core wires, one of which is the signal wire (white) and the other wire is the ground wire (black).

4.4.1.1.3 Three-core cable, two of which are power cables (red for positive and black for negative) and one for signal (green).

4.4.1.2 Core cross-sectional area requirements

Meet the relevant provisions of GB/T 3956 0.3mm2 multi-strand copper wire strand.

4.4.1.3 Core sheath size requirements

The outer diameter of the core insulating layer is 1.6 mm <= phi <= 1.8 mm.

4.4.2 Technical requirements for flat digital temperature measuring cable conductors

In accordance with the requirements of GB/T.20118, the outer diameter of two steel wire ropes phi >= 1.2mm.

4.4.3 Technical requirements for tensile steel wire

4.4.3.1 Technical requirements for tensile steel wire of flat warehouse

4.4.3.1.1 Tensile steel wire in circular digital temperature measuring cable. 1×19 strands of cable, diameter phi>=1.4mm.

4.4.3.1.2 with insulation jacket.

4.4.3.1.3 The minimum breaking force of the wire rope is >=1.9kN.

4.4.3.2 Technical requirements for tensile steel bars for shallow round silos and vertical silos

4.4.3.2.1 The minimum breaking force of tensile steel wire for shallow round silo and vertical silo meets the relevant requirements of GB/T.20118.

4.4.3.2.2 The height of the grain stack is <=15m, the diameter of the double steel wire rope is phi>=3.0mm, and the minimum breaking force is >=10.1kN.

4.4.3.2.3 15m< stack height <=25m, double wire rope diameter phi>=5.0mm, minimum breaking force >=28.2kN.

4.4.3.2.4 25m< stack height <=30m, double wire rope diameter phi>=6.0mm, minimum breaking force >=40.6kN.

4.4.3.2.5 30m< stack height <=45m, double wire rope diameter phi>=7.0mm, minimum breaking force >=55.2kN.

4.4.3.2.6 The height of the grain stack is >=45m, the diameter of the double steel wire rope is phi>=8.0mm, and the minimum breaking force is >=72.2kN.

4.5 Digital temperature measurement cable connector technical requirements

4.5.1 The connector wiring and the connector shall not be exposed to the air after installation, and shall have the ability to resist corrosion of PH3 gas.

4.5.2 The LS/T 1809-2017 anti-fumigation test requirements shall be met.

4.6 Technical requirements for interconnects

4.6.1 Interconnect Outline Dimensions

The outer diameter of the interconnect is phi >= 6.0 mm.

4.6.2 Interconnect wire core size requirements

The single core cross-sectional area of the core is >=0.5mm2.

4.6.3 Interconnect wire core material requirements

Use tinned copper wire cable.

4.7 Technical requirements for digital temperature measurement cable digital sensors

The sensor uses a digital temperature sensor.

4.7.1 Technical requirements for anti-jamming capability of digital temperature sensors

Meets the requirements of 6.9 of LS/T 1809-2017.

4.7.2 Technical requirements for digital temperature sensors

4.7.2.1 Temperature measurement range. -40 °C <= t <= 60 °C.

4.7.2.2 -10 °C <= t <= 60 ° C, the maximum temperature error <= ± 0.5 ° C.

4.7.2.3 -40 °C <= t < -10 ° C, the maximum temperature error <= ± 2 ° C.

4.7.3 Digital Sensor Address Sorting Method

4.7.3.1 The granary detection point sorting method is performed according to 16 bits, and the lower 6 bits of the low byte are layer numbers, counting from 1 .

4.7.3.2 The upper 2 bits of the high byte and the upper 2 bits (higher 10 bits) of the lower byte are the cable numbers, counting from 1.

4.7.3.3 Setting the Digital Temperature Measurement Cable Cable number and the location of the sensor in the cable are listed in Appendix B.

5.1 Performance test

5.1.1 Temperature test

Place the digital temperature measurement cable and standard thermometer in a constant temperature environment for 30 minutes, and measure the temperature and standard thermometer (accuracy level ±0.1 °C) in comparison, the error does not exceed ±0.5 °C.

5.1.2 Sensor Quantity Integrity Test

Connect the digital temperature measurement cable to the system to communicate properly and return the data of the preset number of digital sensors.

5.2 Anti-fumigation corrosion test method

Follow the relevant regulations in LS/T 1809-2017.

5.3 Digital temperature measurement cable tensile strength test method

The tensile strength test of digital temperature measuring cable shall be carried out in accordance with the relevant provisions of GB/T 8358.

5.4 Environmental test

5.4.1 Temperature test

Carry out the temperature adaptability test in accordance with the relevant provisions of GB/T 6587.3.

5.4.2 Humidity test

According to the relevant provisions of GB/T 6587.3, the adaptability test under the corresponding conditions of temperature and humidity shall be carried out.

5.5 Test method for sheath material

According to the relevant provisions of 6.7 of GB/T 9330.2.

5.6 Connector inspection method

Follow the method specified in Chapter 8 of LS/T 1809-2017.

6.1 Product logo

Be clearly marked outside the cable sheath, including at least the cable number, of layers, length, etc.

6.2 Packaging mark

According to the relevant provisions of GB/T 191.

6.3 Packaging

Perform in accordance with the relevant regulations in LS/T 1809-2017.

6.4 Transportation

According to the relevant provisions of GB/T 4798.2.

6.5 Storage

According to the relevant provisions of GB/T 4798.1.

Appendix A

(informative appendix) Calculation of the pulling force of the silo temperature measuring cable A.1 Scope this appendix specifies the calculation formula for the tensile force of the silo temperature measurement cable and the main grain physical property parameters involved in the calculation.

A.2 Calculation of the tensile force of the silo temperature measuring cable A.2.1 Calculation of the tensile force of the silo temperature measuring cable Calculated according to formula (A.1).

2pidrhoµ1

(sgamma-Pv) (A.1)

In the formula.

T --- silo temperature measurement cable tension, the unit is kN (kN);

d --- cable diameter in meters (m);

rho --- silo section hydraulic radius, in meters (m);

11 --- the coefficient of friction of the grain to the cable;

s --- When it is horizontal, it is calculated from the top surface of the warehouse to calculate the depth at the cross section. When the grain surface of the warehouse is sloped, it is the grain cone from the top of the warehouse.

The mental arithmetic calculates the depth at the cross section in meters (m);

gamma --- grain gravity density in kilonewtons per cubic meter (kN/m3);

Pv---Standard value of static vertical side pressure on the horizontal surface of depth s, in units of kilonewtons per square meter (kN/m2);

µ --- The coefficient of friction of the grain on the silo wall can be selected from Table A.1.

A.2.2 Static vertical pressure standard value calculation for deep warehouses, the vertical pressure standard value (Pv) of the grain under static is calculated according to the Yangsen formula [formula (A.2)].

Gammarho

(1-e-µks/rho) (A.2)

In the formula.

Pv---Standard value of static vertical side pressure on the horizontal surface of depth s, in units of kilonewtons per square meter (kN/m2);

gamma --- grain gravity density in kilonewtons per cubic meter (kN/m3);

rho --- silo section hydraulic radius, in meters (m);

s --- When it is horizontal, it is calculated from the top surface of the warehouse to calculate the depth at the cross section. When the grain surface of the warehouse is sloped, it is the grain cone from the top of the warehouse.

The mental arithmetic calculates the depth at the cross section in meters (m);

µ --- The friction coefficient of grain on the silo wall can be selected from Table A.1;

k --- grain side pressure coefficient.

A.2.3 Calculation of grain side pressure coefficient the side pressure coefficient of grain is calculated according to formula (A.3).

k=tan2 45°-phi2

1-sinphi

1 sinphi

In the formula.

k--- grain side pressure coefficient;

phi---The internal friction angle of grain, which can be equal to the angle of repose, in degrees (°).

A.2.4 Calculation of hydraulic radius of silo section for the silo rho = dn/4, for the square silo rho = a0/4.

For a regular polygonal silo rho=dn/4, dn is the inscribed circle diameter of the regular polygon.

For the short-side net length a0, the long-side net length b0 of the rectangular block hydraulic radius is calculated according to the formula (A.4).

rho=

A0b0

2(a0 b0)

In the formula.

rho --- rectangular section hydraulic radius, in meters (m);

A0---Rectangular length, in meters (m);

B0---Long side long and long, the unit is meters (m).

A.3 Description of the calculation of the tensile force of the temperature measuring cable when the cable cross section is circular and the full length section is unchanged, it should be based on the characteristic parameters of the temperature measuring cable, the silo diameter, the grain height and the storage.

For the physical property parameters of the grain variety, the standard value of the friction load is calculated according to the formula (A.1). The maximum value of the standard value is the temperature measurement of the warehouse.

The tensile value of the cable.

The grain physical property parameters gamma, phi, µ, etc. should be determined by test analysis. When there is no test data, it can also be taken according to Table A.1.

A.4 Main grain physical property parameters the gravity density, internal friction angle and friction coefficient of the main grain are shown in Table A.1.

Table A.1 Main food physical property parameters

Material name

Gravity density gamma kN/m3 Internal friction angle phi (°) Friction coefficient µ Pair of concrete slabs Rice 6.0 35 0.50 0.35 Rice 8.5 30 0.42 0.3 Corn 7.8 28 0.42 0.32 Wheat 8.0 25 0.4 0.3 Soy 7.5 25 0.4 0.3 Barley 6.5 27 0.4 0.4 Flour 6.5 40 0.3 0.3 Bran 4.0 40 0.3 0.3 Sunflower seeds 5.5 30 0.4 0.3 Appendix B (informative appendix) Address setting instructions for digital temperature measurement cable production Take DS18B20 as an example for explanation.

The number of the sensor for temperature measurement is stored in the sensor's cache, as shown in Figure B.1. In the cache Byte2 and byte3 are numbered addresses, which are TH user byte 1 and TL user byte 2, respectively. This sensing during the cable manufacturing process the numbered position set by the device should be exactly the same as the position set by the TL user. Write continuously 3 during the programming of the sensor Bytes, TH User Byte, TL User Byte, and Configuration Register.

* The power-on state depends on the value in the EEPROM.

Figure B.1 DS18B20 memory map

Appendix C

(informative appendix) Installation instructions for temperature measurement cable C.1 flat warehouse Installation of temperature measurement cable in the warehouse.

a) Use reserved holes in the building, concealed in the warehouse, the spacing should correspond to the distance between the temperature measurement cable columns;

b) When the window, column, and door are encountered, the distance between the reserved hole and the window, column and door is generally greater than or equal to 0.2m;

c) The extension and ventilation fan controllers are placed in the extension rain box, and the installation position of the extension rain box must avoid the facilities outside the warehouse and leave an operating space greater than or equal to 1 m.

C.2 shallow silos and silos Installation of shallow silos and vertical silo temperature measuring cables.

a) The splitter should be placed in the outdoor protective box;

b) The temperature measuring cable should be installed by the roof method, and the rainproof and sealing treatment of the roof hole should be done;

c) If there is difficulty in opening the top of the warehouse, the centralized outlet method in the warehouse can also be used;

d) All the cables on the silo are installed by wearing protective tubes;

e) The upper end should be fixed by flange, and the lower end should be fixed with a positioning weight or temperature measuring cable.