FC-201B hot network wireless monitoring solution
Abstract: With the rapid development and popularization of modern computer and communication technology, the full realization of modernized steam management has become an inevitable trend. In the process of heat network reform, how to shorten the meter reading cycle, quickly find the meter failure, leak steam, steal steam, save meter reading personnel, reduce tube loss, etc. are all problems that need to be solved.
Keywords: radio telemetry hot network vortex flow meter
With the continuous development of hot users, our company's hot users have expanded to more than 70, and the heat supply reaches as far as three or four kilometers. Every day, our hot network management personnel must go to the hot user to read the meter, and count the heat supply and tube loss on the day. The workload of walking 20 or 30 kilometers per day is quite large. Moreover, it is impossible to find the power outage, instrument, component failure, steam leakage and stealing of the instrument in time. In order to keep abreast of the user's steam consumption, the analysis of the tube loss can facilitate key transformation and reduce the burden on the heat network management personnel. The company decided to install a monitoring system that can monitor the temperature, pressure, instantaneous flow, and cumulative flow of the user's steam at any time.
First, the program design
The on-site secondary flow meter is uploaded to the serial port of the computer through the RS232 interface. There are two kinds of signal transmission methods: one is wired transmission, and the other is wireless transmission. The advantage of wired transmission is that the anti-interference ability is strong without error code. The disadvantage is that the line is too long, the construction is difficult, and the cable cost is high. If there is a problem with the cable in the future, it is not good to find the breakpoint. The advantages of wireless transmission are convenient construction, low cost and convenient maintenance. The disadvantage is poor anti-interference ability. Considering the difficulty of construction and future maintenance, we chose radio telemetry.
1. The transmitting and receiving stations use the wireless digital radio station of Shenzhen Youxunda Communication Equipment Co., Ltd. The system structure diagram is as follows:
Click here to view the picture in a new window
At the highest point of the office building in the factory, the height of the center radio antenna (the higher the better), FC-208/d as the main station, communicate with the computer through COM1, the communication protocol adopts RS232 mode. The local flow meter is connected to the FC-201/B digital radio station by RS232.
2. The secondary flow meter uses the vortex flow meter of Nantong Flowmeter Factory. In the case of ensuring the original accuracy, an RS232 communication interface is added. The data is transmitted to the FC-201/B digital radio station by digital interface through a single interface. So the data we see in the office is the same as the data on the spot, there is no deviation.
3. The computer adopts Lenovo host PIII 1.2G/128M/40G/17CRT.
4. The configuration software adopts force control configuration software with a maximum capacity of 100 users.
Second, the working principle
The computer connects to the main station through the serial port and issues an acquisition command. The local radio station sends the command to the flow meter. If the meter number in the command matches its own bit number, the temperature, pressure, instantaneous flow rate, and accumulated flow signal are sent out. The main station receives the signal and saves it to the computer. On the hard disk.
Third, the system function
1. If the computer in the local area wants to view the data, just open the IE browser and enter the IP address of the machine in the address bar to see the usage of each user. This makes it easy for company personnel to understand the use of steam. Up to ten computers can simultaneously browse user data online.
2. On the main screen, we divide the two buses according to the distribution of the hot users, and the west line is divided into four branches. Users are arranged from near to far, and a summary table is installed on each bus and branch line. Through comparison of various parameters, tube loss, pressure loss and temperature drop can be seen at a glance, and at the same time, a meter with inaccurate measurement can be found, for example The closer the pressure to the master table, the higher the temperature should be. If it is not in descending order, it indicates that there is a problem with the meter.
3, you can find the data of each user at any time (the number of days of historical data that can be queried depends on the size of the hard disk).
4. The report function can output the data of each user for one day (interval of one hour). The daily report automatically counts the steam consumption of each user on the previous day, the tube loss of the branch line, and the total tube loss; the monthly report automatically counts the previous month. Steam consumption per user, tube loss of branch line, total tube loss.
5. When the data exceeds the set value, it will issue a data violation alarm or a device failure alarm will be issued after receiving the signal.
6. You can stop or start data collection for each user online (log in with engineer level). In this way, one hundred users can be configured at one time, and the user who has not yet installed is stopped first, and the device can be directly started without reconfiguration.
7. The alarm parameters and user name can be modified online (login with engineer level).
Fourth, problems and experience in installation and commissioning
1. If the radio antenna is installed at an outdoor altitude, a lightning arrester should be installed to prevent lightning.
2. The power of the radio is as large as possible, and the antenna is as high as possible, so the signal will be better.
3. The sampling period is preferably 2~5 minutes. It is too short for the radio to transmit too frequently, and the life is greatly shortened, which affects the real-time performance of the data.
4. The instrument number sometimes becomes wrong. The data cannot be uploaded because the antenna is too close to the meter. After removing the antenna, the program has not been modified.
5. During normal operation, some devices may not be collected for three consecutive times due to interference or other reasons. The device is considered to be faulty or non-existent, and the device is no longer collected. After a few hours, the equipment was resumed. This design idea does not meet the site requirements. The environment around the radio and the weather may affect the transmission of the signal. We redesigned the computer's I/O acquisition driver to set up all devices to be collected once in a single cycle, regardless of the presence of the device. This prevents the device from being collected for a long time after the acquisition is interrupted due to interference. By this design, the data interruption time is greatly shortened. The real-time nature of the data is guaranteed.
6, the installation of the vortex flowmeter should pay attention to the front can not have a pressure reducing valve, otherwise, the flow rate of steam after passing through the pressure reducing valve is too fast, causing loss of wave. There should be no vibration sources around, such as air compressors, otherwise the vibration frequency of this part will be superimposed.
7. The instrument power supply is powered by ~220V and backup DC 12V rechargeable battery, which can guarantee that the instrument can run for three days after ~220V power loss. However, the transmitting station does not connect to the backup power supply. When the data is not transmitted for a long time, the heat network personnel should go to the site to check whether it is ~220V power loss or meter problem. This design not only ensures the normal metering of the instrument, avoids economic loss, but also timely discovers the system power loss and timely processing.
Fifth, the use of the system
The system has been put into operation for nearly half a year, and 43 units have been installed. After continuous improvement, the configuration from the underlying I/O driver to the upper layer has undergone major changes. It has been perfected, and there is no crash in the system. Users who are far away from the system sometimes have data collection. After the unified operation last year, by comparing the historical records of pressure and flow, it was found that four or five users could steal steam, and the winter pressure gauge tube freezing and instrument failure could be discovered in time. Avoid economic losses.
Sixth, the conclusion
With the continuous installation of telemetry instruments, the labor intensity of our heat network managers is greatly reduced. The user's use of steam is also clear at a glance, which greatly facilitates the decision of the company's leadership. This system is worth promoting in the group company.