The digital sensing device of on-line measurement grain depot foodstuffs temperature, moisture
Technical field
The present invention relates to grain depot foodstuffs temperature, water content detection field, specifically is the digital sensing device of a kind of on-line measurement grain depot foodstuffs temperature, moisture.
Background technology
No matter be in the daily keeping of grain depot, still cooling ventilation, the precipitation at grain ventilate, in the modified ventilation, the temperature of grain, the on-line measurement of moisture are absolutely necessary.On-line measurement requires the monitoring point level interval less than 5 meters, and vertical interval is less than 2 meters; Require cereal temperature, the moisture repetitive error of measurement the smaller the better, the temperature repetitive error is preferably smaller or equal to 0.1 degree centigrade, and the moisture repetitive error, just can be monitored to as long as the grain state that is in like this in the keeping has subtle change preferably smaller or equal to 0.02%.Because technology and cost, the on-line measurement system of existing being known as " grain information monitoring system " can only be measured the temperature and the inside and outside aerial temperature and humidity of silo of grain, moisture that can't on-line measurement grain.The measurement of the moisture of grain can only section be taken the laboratory measurement behind on-site sampling, its measuring method has the oven drying weight method and adopts quick drimeter to measure.In grain purchases, the quick grain moisture content analyser of inserted-link type is arranged, also being not suitable for fathoms reaches 6 meters even darker grain heap, can not on-line measurement.The grain moisture content sensing device that is used for grain drying device is owing to the on-line measurement of reason also is not suitable for being applied to silo grain such as structure and repetitive error be bigger.Before, also there is the system of the moisture of some on-line measurement grains to test, do not adopted in actual use because of the sum of errors repetitive error is big and price is higher eventually by grain depot at indivedual grain depots.Make the existing grain information monitoring system that is applied to the grain depot temperature and the moisture of online accurate measurement grain simultaneously.
Summary of the invention
The present invention provides the digital sensing device of a kind of grain depot foodstuffs temperature of on-line measurement cheaply, moisture in order to solve the existing grain information monitoring system that is applied to the grain depot temperature of online accurate measurement grain and the problem of moisture simultaneously.
The present invention adopts following technical scheme to realize: the digital sensing device of on-line measurement grain depot foodstuffs temperature, moisture, comprise the tension wire rope, several along the fixing cereal temperatures parallel with one another of tension wire rope, moisture transducer, outside be wrapped in tension wire rope and cereal temperature, the outer plastics covering of moisture transducer, the digital data transmission line of each cereal temperature, moisture transducer is continuous.
The present invention is fixed on a plurality of cereal temperatures parallel with one another, moisture transducer on the same tension wire rope according to the order of sequence, and it is the digital data transmission line of each cereal temperature, moisture transducer is continuous, encapsulated with plastics then, formed flexible cable shape multimetering device; During use, with tension wire rope one end knot ring, utilize stock to cooperate with the knot ring of wire rope one end, the digital sensing device of shape of the present invention such as cable is pulled in the grain in the silo, with after computing machine is connected, can realize the temperature and the moisture measurement of grain through data forwarding device.Because each cereal temperature, the shared single data signal transmssion line of moisture transducer, therefore, need under corresponding software is supported, make each cereal temperature, moisture transducer that an address date sign that is different from other sensor be arranged, when the sensor that is connected in parallel only receives the order that meets own address, just send the temperature, the moisture data that record by itself.
Described cereal temperature, moisture transducer comprise the hard plastic tube that is built-in with thermistor, the cover formation that is fixed in the hard plastic tube two ends detects the metallic cylinder of electric capacity respectively, are provided with in the hard plastic tube to be used to measure the metering circuit that detects electric capacity and thermistor variable quantity.
Described cereal temperature, moisture transducer can be measured the temperature and the moisture of grain simultaneously: with the temperature variations of grain in the thermosensitive resistance measurement grain depot; The metallic cylinder that is fixed in the hard plastic tube two ends with cover constitutes detection electric capacity, in the time of in sensor is put in grain depot, grain in the grain depot riddles around the sensor, and as the dielectric medium that detects between the electric capacity, the specific inductive capacity of water will be far longer than the specific inductive capacity of grain, the variation of grain moisture content causes the change in dielectric constant that detects between the electric capacity, and then causes the capacitance variation that detects electric capacity, detects the change of soil water content that the changes in capacitance amount is measured grain by measuring.Final measuring grain moisture content value also needs to demarcate under different in moisture by the grain to different cultivars, and needs to revise with temperature value, owing to the degree of depth unit weight that grain is different is also different, also needs revise this.
When application digital sensing device of the present invention makes up grain information monitoring system, each silo is provided with one " extension set ", be somebody's turn to do " extension set " and indoor " main frame " of observing and controlling and carry out exchanges data, can adopt wire communication mode, also can adopt wireless communication mode, adopt " extension set " of wireless communication mode to transmit data by other wireless " extension set "; Each silo is provided with the headend that directly links to each other with digital sensing device, this headend is by " extension set " swap data of wireless or wired mode and silo, headend not only with digital sensing device inner sensor swap data, and provide power supply for sensor; Wireless headend can be used powered battery, and wired headend needs " extension set " to provide power supply for it.Each warehouse of grain depot can place tens even the described digital sensing device of the basic invention of hundreds of, not only can satisfy the many especially needs of grain depot measurement point fully, and the cost of each cereal temperature, moisture transducer is very low, makes that the overall cost of grain information monitoring system is lower.Through facts have proved, the temperature repetitive error that digital sensing device of the present invention is measured is smaller or equal to 0.1 degree centigrade, and the moisture repetitive error is smaller or equal to 0.02%.
The present invention is rational in infrastructure, adopts digital transmission mode, and cost of manufacture is low, can online accurate measurement silo in the temperature and the moisture of grain, be the existing desirable upgraded product of grain information monitoring system.
Description of drawings
Fig. 1 is a structural representation of the present invention;
Fig. 2 is the structural representation of cereal temperature, moisture transducer;
Fig. 3 is the A-A cut-open view of Fig. 2;
Fig. 4 is the circuit theory diagrams of cereal temperature, moisture transducer;
Among the figure: 1-tension wire rope; 2-cereal temperature, moisture transducer; 3-plastics covering; The 4-hard plastic tube; 5,6-metallic cylinder; The 7-metering circuit.
Embodiment
The digital sensing device of on-line measurement grain depot foodstuffs temperature, moisture, comprise tension wire rope 1, several along the fixing cereal temperatures parallel with one another of tension wire rope 1, moisture transducer 2, outside be wrapped in tension wire rope 1 and cereal temperature, the outer plastics covering 3 of moisture transducer 2, the digital data transmission line of each cereal temperature, moisture transducer 2 is continuous.Described cereal temperature, moisture transducer 2 comprise the hard plastic tube 4 that is built-in with thermistor, the cover formation that is fixed in hard plastic tube 4 two ends detects the metallic cylinder 5,6 of electric capacity respectively, are provided with in the hard plastic tube 4 to be used to measure the metering circuit 7 that detects electric capacity and thermistor variable quantity.
During concrete enforcement, described metering circuit 7 comprises capacitance measurement chip IC 2 and microcontroller IC1, metallic cylinder is as the electrode electrode1 that detects electric capacity, electrode2 respectively with the CIN pin of capacitance measurement chip IC 2, the EXC pin links to each other, the thermistor NTC G1 pin with microcontroller IC1 of connecting with the series arm of resistance R 5, between the GND pin, thermistor NTC links to each other the data signal transmission end SDA of capacitance measurement chip IC 2 with the connected node of resistance R 5 with the G0 pin of microcontroller IC1, SCL is through the data transmission terminal GP5 of I2C bus and microcontroller IC1, G4 links to each other.Wherein, capacitance measurement chip IC 2 adopts the AD7151 chip, and microcontroller IC1 adopts the chip PIC12F675 or the PIC12F615 that carry analog-digital conversion function and internal clocking of low cost, low pin count.
For the ease of the connection between adjacent cereal temperature, the moisture transducer 2, cereal temperature, moisture transducer 2 shared power lead, ground wire, digital data transmission lines are integrated on the circuit board in the cereal temperature, moisture transducer 2, and be provided for three lead-in wires that power lead, ground wire, digital data transmission line connect at the sensor two ends, so just can realize the parallel connection use of several or tens cereal temperatures, moisture transducer 2.
In addition, can insert easily in the grain in order to make digital sensing device, the integral diameter of digital sensing device should be as far as possible little, is no more than 10 millimeters.Below the manufacturing process of digital sensing device of the present invention is described below (following size is only as an example, other size also can): (1), two metallic cylinder 5,6 external diameters are 8 millimeters, length respectively is 20 millimeters, thickness is 0.1 millimeter, be fixed on the hard plastic tube 4 with rotational symmetry at a distance of 10 millimeters, forming an external diameter is 8 millimeters, and length is 50 millimeters, thickness is 1 millimeter pipe, has constituted the main external structure of cereal temperature, moisture transducer 2; (2), the length that will be provided with metering circuit 7 is that 60 millimeters, width are that 6 millimeters circuit board inserts in this pipe, three lead-in wires are respectively drawn at the two ends of circuit board, be respectively power lead, ground wire, digital data transmission line, two metallic cylinder are connected to metering circuit on the circuit board by two metal short leads respectively, form cereal temperature, moisture transducer 2; (3), a plurality of such cereal temperatures, moisture transducer 2 spacing as requested are connected to each other together with three leads, increase each cereal temperature of tension steel wire penetrating of 2 mm outer diameter of tensile strength, the inside of moisture transducer 2 with one, be 10 millimeters flexible cable apperance with the cable former it being squeezed into external diameter with such integral body behind the pvc material hot melt then, promptly obtain the digital sensing device of on-line measurement grain depot foodstuffs temperature of the present invention, moisture.