Cold storage temperature monitoring system
Cold storage temperature monitoring system
I. overview of the programme
1) this scheme is a full digital scheme, the output of each temperature 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 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 can be connected with the 64 temperature sensor 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 site 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)   uses low power design, only needs to collect and the controller power supply, does not need to supply electricity to the sensor, the spot power supply spot is few, the construction is convenient.
Two. Product Brief
1. acquisition module
Temperature measurement characteristics:
The United States supports the full range of DALLAS 1-wire bus digital temperature sensor, temperature measurement points: 1 to 64 points, the measuring range of temperature measurement accuracy of -55 ~ +125 C + - 0.5 DEG, temperature resolution: 9 ~ 12 (0.0625 C). Temperature measurement speed: > 40 points /s. Support temperature measurement
Cable length: 200M, sensor support two 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 adopt RS485 communication, an upper computer can take many modules, baud rate 9600/19200/38400 optional. And can be extended to Ethernet interface communication module.
12V/24V/48V input (external, optional).
Module operating temperature: -25 ~ 85 DEG C.
The module is made of plastic / metal shell, which is more suitable for the worse site requirements. The terminal is made of standard interface, which makes the field connection more simple and convenient. The module uses the latest technology to support the American DALLAS full range 1-wire bus digital temperature sensor (DS18B20), and supports "two lines" or "three lines" in two ways, so that users are more convenient to use. Each module can connect seven temperature measuring cables, each cable can be installed up to 64 temperature points. The module automatically detects the number of sensors, and the ID automatically sorts. Real time refresh data buffer. The standard RS232 communication mode is used between the module and the host computer, and the communication conversion module is not needed.
DS18B20 "one wire bus" digital temperature sensor;
Ultra small stainless steel metal package temperature sensor;
RS232 interface multipoint temperature acquisition module;
RS485 interface multipoint temperature acquisition module;
Ethernet interface multipoint temperature acquisition module;
Typical applications: cold storage, temperature measurement, concrete monitoring equipment, cabinet temperature measurement, air conditioning testing line, building automation, etc..
2. digital temperature sensor DS18B20 and its waterproof package HXRS6671
Dallas semiconductor digital temperature sensor DS1820 is the world's first to support the "1-wire bus" interface temperature sensor. The unique and economical characteristics of the 1-wire bus enable users to easily build sensor networks and introduce new concepts for the construction of measurement systems. Now, the new generation of "DS1820" is smaller, more economical and more flexible. So that you can give full play to the advantages of "one line bus".
like DS1820, DS18B20 also supports the "1-wire bus" interface, measuring temperature range of -55 degrees C to +125 degrees, in the range of -10 to +85 degrees centigradeThe accuracy is + 0.5 centigrade. The field temperature is directly transmitted in the digital transmission mode of "one wire bus", which greatly improves the anti-interference performance of the system. Field temperature measurement suitable for harsh environments, such as environmental control, equipment or process control, temperature measurement, consumer electronics, etc..
unlike the previous generation, the new product supports the voltage range of 3V to 5.5V, which makes the design of the system more flexible and convenient. And the new generation is cheaper and smaller.
DS18B20; the program can set the resolution of 9~12 bits, the accuracy is + 0.5 degrees centigrade. Optional smaller package, wider voltage range. Resolution settings, and user set alarm temperature stored in the EEPROM, still stored after power down. DS18B20's performance is the best in a new generation of products! The performance price ratio is also excellent!
It can provide general standard interface or customize the interface according to customer's special requirement.
The standard interface can realize functions, such as monitoring point, real-time display, real-time curve, history curve, upper and lower alarm.
The following functions can be used as a reference when customizing the interface
A. can display the location of alarm points in the plane plan, which is convenient for engineering personnel to maintain. When the B. alarm happens, the computer sound card can be controlled, and the voice alarm can be carried out.
Three. System structure diagram (Ethernet temperature acquisition module)