In the production of clinker, it is particularly important for the cement plant to know the real-time inventory of clinker in the clinker warehouse. Therefore, the cement plant installed a radar level meter on the top of the clinker warehouse for real-time monitoring. The radar level meter needs to be installed to the clinker warehouse. The roof of the warehouse is relatively high from the ground reference. It is faced with the problems of achieving stable data transmission with the monitoring computer. It is difficult and costly to lay lines, and it is difficult to maintain the lines in the future. Therefore, a method that is easy to maintain and relatively low-cost is needed. A data transmission method with low cost and relatively stable data transmission.
1. Working principle and technical characteristics of wireless bridge
Wireless bridges are actually bridging wireless networks. They use wireless transmission methods to establish communications between two or more networks. From the communication mechanism, they can be divided into circuit-type bridges and data-type bridges. The data-type bridge we use adopts the IP transmission mechanism, and the interface protocol is implemented using the bridging principle. Its characteristics in the 2.4G or 5.8G wireless license-free frequency bands determine that it has advantages over traditional limited networks in long-distance data transmission. The advantage of easier setup and deployment.
Wireless bridge transmission standards often use 802.11b or 802.11g, 802.11a and 802.11n standards. The data rate of the 802.11b standard is 11Mbps. On the premise of maintaining sufficient data transmission bandwidth, 802.11b can usually provide actual data rates of 4Mbps to 6Mbps. Data rate, while 802.11g and 802.11a standard wireless bridges have a transmission bandwidth of 54Mbps, and their actual data rate can reach about 5 times that of 802.11b. Currently, the transmission bandwidth can reach up to 108Mbps through turb and Super modes; 802.11n Typically can provide transmission rates of 150Mbps to 600Mbps. Under normal circumstances, the speed and stability of its data transmission can be guaranteed.
2. On-site installation and implementation methods
First, we connect the on-site radar level and wireless bridge to the radar level meter through POE. The data transmission port is connected to the radar level meter. The bridge power supply port is directly connected to the wireless bridge. DC12~24V is passed through the power supply. The adapter is connected to 220V AC to power the bridge. Use the same method to connect the data interface of the other wireless bridge to the network card of the testing computer or its upper switch. After the installation is completed, the bridge angle needs to be adjusted on the top of the library. Keep the antennas of the two bridges facing each other as much as possible to ensure the stability and efficiency of data transmission, as shown in the figure. Picture 1 and 2 show the on-site installation locations of the monitoring location and the top of the clinker warehouse respectively.
Picture 3 shows the stability test of data transmission between the detection computer and the on-site material level meter. It can be seen that the data transmission has a certain stability.
When using the conventional method to transmit data between the radar level meter and the detection computer, more cables need to be laid to ensure data transmission, and the top of the storage warehouse of a conventional cement plant is generally higher than the ground datum, so laying lines and There are certain difficulties and risks in the later maintenance of lines. Using high-power wireless bridges to realize data transmission between two points has the advantages of being more convenient, faster, economical, and better maintained than traditional line transmission.
by Yaping Shi
