With the continuous improvement of coal mine modernization, the requirements for the stability, safety and uninterruptedness of underground power supply and distribution system in coal mine are becoming higher and higher. Most of the high-voltage and low-voltage integrated protectors used in coal mine power supply have RS-485 communication interface, but there are many kinds and specifications, long product time span and various communication protocols, which bring difficulties to the construction of underground power supply monitoring system. In this paper, high-speed intelligent programmable serial controller is used to construct power supply monitoring system in underground coal mine, which solves this kind of problem. The system has been tested in Qinan Coal Mine of Huaibei Mining Group Company in Anhui Province for a long time and runs reliably. The polling system is used in the underground serial communication of coal mine, that is, when the communication rate of bus is constant, the refresh time of system data is equal to the communication time of a single extension * the number of extension bus usage rate. Improve bus usage. Add an appropriate device between the computer and the extension.
When the computer does not communicate with the following extension, the device continues to communicate with the extension, and stores the data in its own cache. As long as the computer needs the data, it immediately distributes the data to the computer wholesale through ethernet. The architecture of PSC is based on ARM processor. The ARM processor uses 32-bit embedded ARM Cortex SCM STM32F103x as the CPU of PSC. Each processor has two serial ports that can be processed in parallel. There are four processors, which can process eight serial ports in parallel. The device can be grouped and batched according to address, and communicated in batches with large capacity cache.
The processing speed is fast and compatible with the field. The same kind of communication protocol. PSC has the characteristics of program storage and independent operation. The communication protocol of comprehensive insurance is converted and stored on PSC. In the coal mine power supply monitoring system, it is difficult to confirm whether the output signal of the site comprehensive insurance is intrinsically safe through the correlation test.
According to the regulation of GB3836, the connection between non-intrinsic safety RS-485 signal and intrinsic safety equipment needs signal isolation processing, i.e. a RS-485 signal isolator should be installed between non-intrinsic safety signal and intrinsic safety equipment.
In this paper, ADM2483 is selected as the isolation chip matched with PSC. The magnetic coupling isolation channel and RS-485 transceiver are integrated in the chip. The design circuit is simple and convenient. RS-485 signal isolation can be realized by a single chip. The product is small in size, power consumption is only 1/10 of the traditional optocoupler isolation, transmission delay is ns level, and reliability is high, which enhances the security and anti-interference of signal transmission. PSC has programmable function using PC programming language, and has strong expansibility and integration. Using programming tools, different communication protocols can be converted into standard protocols, so as to achieve the function of supporting communication between different integrated protection devices without changing the comprehensive insurance. The software of programming development platform matched with PSC is Rstep. The software is programmed by ladder diagram. The ladder diagram is very similar to the circuit diagram of the electrical control system. It has the advantages of intuition and understandability, and is easy to be mastered by factory electrical personnel. In this paper, PSC technology is used to construct the underground power supply monitoring system of coal mine, which adopts three layers network structure: management layer, information layer and equipment layer. The main ground control station and the dispatch management center constitute the management layer. Industrial Ethernet communication is adopted, which is based on the EtherNet/IP network structure of IEEE802.3 standard. The equipment group is connected to the industrial network switch point to point, and the switch provides RJ-45 or SC ports. The transmission rate is 1000/100Mbps, and the transmission medium is single mode optical fiber or five kinds of twisted pair shielded wire. The underground ring network and the ground network constitute the information layer. The information layer is an EtherNet/IP network structure based on IEEE802.3 standard. The communication between monitoring substation and underground ring network switch is based on ethernet. The monitoring substation and monitoring substation are connected by underground ring network, and the underground ring network is connected by optical fiber and ground network. The device layer consists of integrated protector, transmission bus and monitoring substation.
The integrated protector is connected to the Monitoring Sub-station through bus, and the PSC in the Monitoring Sub-station transforms different protocols and stores them. The monitoring substation is connected with the underground switch through ethernet. Each PSC has two serial ports that can be processed in parallel.
It can process eight serial ports in parallel. It can group and batch the comprehensive insurance according to address, which improves the real-time performance of the system.
The system runs reliably and fast, thermostatic element and the response time is less than 1 s. In this paper, the underground power supply monitoring and control system of coal mine, the controlled equipment is batched and batch communication is implemented, which solves the problems of low speed and long delay time in medium and large-scale application of field bus communication, and also solves the access problem of equipment with different communication protocols. The system has been proved to be reliable.