Soil box temperature monitoring system
simple scheme of soil multipoint temperature monitoring; - cylinder case
, 1, system advantages:
1) this scheme is a full digital scheme, the output of each temperature and humidity probe is directly networked digital signals.
2) because of the adoption of advanced digital and network technology, the scheme is convenient and economical according to the network wiring.
3) because each temperature and humidity probe output directly to the network digital signal attenuation, signal transmission process does not affect the accuracy of the system, and the transmission distance is long, each outlet "bus line" can be connected with 64 temperature or temperature and humidity probe distance up to 200M.
4) the acquisition module automatically identifies the type, quantity, configuration and expansion of the sensor. It can select the location of the module and the number of modules in order to reduce the cost according to the installation conditions.
5) the host computer and the acquisition module use a multi station communication protocol with a distance of 1.2 kilometers;
6) adopt the configuration software technology based on win98/nt platform, and can generate personalized man-machine interface conveniently and quickly according to different customer requirements.
7) a standardized bus design that facilitates the expansion of control and other functions and interconnects with other systems.
8) using low power design, only power supply to the collector, no need to supply power to the sensor, less on-site power supply, convenient construction.
The system configuration is divided into the following parts:
1. host computer:
Functions: data processing and user interface.
Hardware requirements: Pentium 133/32M, DRAM or more /4.3G compatible or industrial computer.
Software: optional configuration software or custom program.
2. isolated RS232/485 communication converter HX-6520: with overvoltage, over-current, surge, isolation, lightning protection.
3. field acquisition module HX6003:
Function: to realize the communication between two levels of communication network. The first level is the upper computer, the RS-485 network, the HX6003 module as the sub station, the other level "one wire bus", the HX6003 module as the acquisition center, and the digital temperature sensor on the cable is measured.
Hardware requirements: with overvoltage, over-current, surge, isolation, lightning protection.
4. digital temperature measuring chip -DS18B20:
Function: implement temperature measurement.
Hardware requirements: dedicated temperature measurement cable, from the acquisition speed and transmission distance considerations, the use of 3 core cable, length of up to 200M, or even longer.
Function: to achieve multi-point temperature measurement transmission.
² HX6003 RS485 temperature acquisition module is introduced
Temperature measurement characteristics:
Support the United States DALLAS full range of 1-wire bus digital temperature sensor ---- temperature measurement points:
1~128 points, the temperature range: -55 ~ +125 degrees centigrade, temperature measurement accuracy: + 0.5 degrees, temperature resolution:
9~12 bit (0.0625 DEG C). Temperature measurement speed: > 40 points /s. Support for measuring cable length: less than 200M,
Support sensor line or three wire connection mode, automatically identify the number of sensors, ID automatic sorting.
Communication characteristic of same host computer:
The module and the host computer use RS485 communication, a host computer can take 127 modules, baud rate 9600/19200/38400 optional. 485 bus transmission distance: 1200M. DLL library and routines to provide support for a variety of configuration software.
24V input (optional 12V/48V).
Module operating temperature: 0~70 DEG C, storage temperature: -25 ~ 85 DEG C. Size: 120 (long mm) *80 (wide mm) *40 (high mm)
The universal remote temperature measurement module is economical and easy to use. The use of more suitable site requirements, plug pluggable terminal convenient, support the full range of DALLAS 1-wire bus digital temperature sensor (DS18B20), and the support of the "two line" or "three lines" in two ways, the application users more convenient. Each module can connect eight temperature measuring cables, with a maximum of 64 temperature points. The module automatically detects the number of sensors, and the ID automatically sorts. Real time refresh data buffer. Data exchange is carried out between the module and the host computer in RS-485 mode.
Test software interface
Introduction of DS18B20 digital temperature sensor
Dallas semiconductor digital temperature sensor DS1820 is the world's first to support the "1-wire bus""
Interface temperature sensor. The 1-wire bus is unique and economical, enabling users to easily build sensor networks
It introduces new concepts for the construction of measurement system. The new generation of DS18B20 is smaller, more economical, and more accurate
Better and better consistency.
DS18B20, the temperature range of measurement is -55 DEG C to +125 DEG C, and the accuracy is between 0.5 -10 and +85 DEG c..
The field temperature is directly transmitted in the digital transmission mode of "one wire bus", which greatly reduces the number of cables and improves the system
The stability and anti-interference of the system.
RS232-485 conversion module
The RS485 interface unit uses only three signal lines, RXD, TXD, and GND, without requiring other directions to control the signal line.
Data stream can realize automatic direction finding, automatic baud rate adaptation and so on.
1. power requirements : DC, 9V, to, 30V300 mA (max.) at 9V
2. operating temperature : 0~55 DEG C
3. work humidity : 5 ~ 95%RH
4. storage temperature : -20 DEG C to 85 DEG C