Agricultural things - the optional temperature and humidity sensors articles (Hong original control)
Temperature and humidity sensor selection techniques
table of Contents
Temperature and humidity sensors 1 Introduction
2 ranked first
Temperature and humidity sensors shelter (a-products) 2
The second is such a sensor 2
The third is that the sensor 3
The fourth sensor imports 3
Recommended fifth hung temperature and humidity sensor 4
Industrial quality for many years 4
4 summary
A sensor monitoring unit belongs, so the quality must be good if the measurement is not accurate to control how the algorithm, a logic control data in the fast hardware monitoring inaccuracies is wasted. 4
Finally, attach the video to take a look 4
Temperature: cold measure physical quantity of the object is one of seven fundamental physical quantities in the International System of Units. In the production and scientific research, people's lives in many physical phenomena and chemical processes are carried out at a certain temperature and is closely related to him.
Humidity: Humidity long time ago there is a close relationship with life, but with a number to indicate more difficult. There humidity representation of absolute humidity, relative humidity, dew point ratio, moisture and dry gas (volume or weight) and the like. The most commonly used in daily life represents the relative humidity of the humidity of the air quantity. Expressed in% RH. On the export quantities of relative humidity and temperature are closely related. A volume of the sealed gas, the higher the temperature the lower the relative humidity, the lower the temperature, the higher the relative humidity. Involving complex thermal engineering knowledge.
Measurement parameters: volumetric soil water content
Range: 0 to 100%
Unit:% (m3 / m3)
Output signal: 0 ~ 2V (Voltage) 4 ~ 20mA (Current Mode)
Accuracy: ± 3%
Interchangeable accuracy: <3%
Retest error: <1%
Measuring principle: the principle of frequency domain reflectometry (FDR)
Working current: about 15mA
Operating frequency: 100MHZ
Response time: <1 second
Stable measurement time: 1 second
Operating temperature range: -30 ℃ ~ 70 ℃
Measurement area: 95% of the probes affect the central hub, having a diameter of 7cm, height 7cm cylinder
Probe length: 6cm
Probe diameter: 3mm
Probe material: stainless steel (anti-electrolysis)
A sealing material: epoxy resin (flame black)
Cable length: 1 m standard (GB three-core shielded wire)
Number one
Temperature and humidity sensors shelter (a-products)
Louvered cover advantage is that, if the temperature of the observation light is irradiated directly onto the glass thermometer warming also not accurate air temperature abbreviated temperature. Wall temperature observed use shelter, the shelter is made two-way shutter, is for ventilation, opaque, a thermometer is placed in the shutter box, requires sensing part thermometer make more accurate measurements.
4-20MA or 0-10V interfaces are typically selected of such a sensor is second
Very easy to use, high accuracy, suitable for warehouses, distribution room, office, unattended station house. But for large humidity locations. Even inside the greenhouse. Such a sensor 485 only and no current voltage interface. Not recommended for use in agriculture is that a third sensor
Such a sensor bus belongs to a single sensor, the interface is primarily the corresponding microcontroller, an electronic circuit. Needs with the development. The fourth sensor imports
This is the outdoor temperature and humidity sensors Siemens, the German quality brand. Quality and expensive.
The fifth recommendation hung temperature and humidity sensor
Industrial quality for many years
There is also a sensor that is both waterproof is not afraid of high humidity, prices are cheap hung control sensor. guaranteed quality. Video as evidence. Show in the domestic water repellency test temperature and humidity sensors, the probe is inserted directly inside the mineral water in the test.
to sum up
A sensor monitoring unit belongs, so the quality must be good if the measurement is not accurate to control how the algorithm, a logic control data in the fast hardware monitoring inaccuracies is wasted.