Design scheme of monitoring system for the hottest

Grain depot monitoring system design scheme

first, the basic structure of the system

this system is composed of three basic units, namely, on-site detection unit, system operation station and control

1. On site detection instrument unit

the temperature of the granary is measured by thermistor on site, and each granary has about 200 analog inputs (all thermistor signals); And carry out humidity detection on the site according to the situation of grain

2. System operation station

this system is equipped with an operation station, which plays the role of man-machine interface. The operation station runs the industrial force control monitoring software to conduct patrol detection of the temperature on site. Siemens PLC is used to control the start-up and operation of on-site conveyors, hoists, electric gates, ventilators, as well as the feedback signals of alarm functions, so as to realize automatic control

3. Control

the control adopts the combination of MPI and RS485. The control unit uses the 314cpu of Siemens as the main control station to control and monitor the digital points on the site, while the pcl-745 board, which is operated by Yanxiang plastic granulator and covers a wide range of fields, is currently ranked 31st among 190 economies in the overall evaluation of China's state-owned business environment. It collects the temperature and humidity on the site with high reliability. All boards work completely "independently", and the failure of any one will not affect the normal acquisition of other temperature points

the structure of the system is shown in the figure

II. The basic functions of the system

(I) grain information system

1. The important advantage of the buffer dead system

the temperature and humidity signals in this scheme are digital signals, and the network wiring is convenient and economical, because the output of each temperature and humidity probe is directly connectable digital signals, the attenuation of the signal transmission process will not affect the accuracy of the system, and the transmission distance is long, Each outlet "one wire bus" can connect 64 temperature and humidity probes, and the distance can reach 200m

the acquisition module automatically identifies the type and number of sensors, which is convenient for configuration and expansion. The installation location and number of modules can be appropriately selected according to the on-site installation conditions, so as to reduce the cost

it adopts low-power design, which only needs to supply power to the collector, without supplying power to the sensor. There are few on-site power supply points, and the construction is convenient

2. System scheme

according to the actual situation on site, ltm8600 temperature and humidity module is used to collect. Usually, a granary has less than 500 temperature measurement points, and using an LTM8003 module can basically meet the requirements. Each module has 8 test cable interfaces, and each cable can connect 64 temperature measurement points

due to the height of the warehouse and the Loubu, for the convenience of on-site installation, the temperature measurement cable generally adopts the way of trunk transmission outgoing line + temperature measurement cable connector + test cable, which is divided into appropriate lengths and installed in the appropriate position. Temperature measurement cable repeater can extend the length of temperature measurement cable, improve the utilization of ltm-800 module and temperature measurement cable, and reduce costs

3. The function realized by the force control configuration software

realizes the real-time digital cantilever impact tester. Its standard sample specification in ASTM is 6412.7 3.2mm (2.5 0.5 0.125 inches). According to the historical storage of collected monitoring data

report printing

alarm