| With the telephone more widely used in a city, more and more communications cables are laid down.Meanwhile work payload of maintainers in communication cable maintaining become larger and larger.It is because that inflation method is commonly used to prevent cable from moistening and enhance insulation strength.Commonly, a local office layout inflation equipment and charge cable with dry air to keep pressure in the cable.In a medium sized city, the local office need layout 20~30 cables with more than one thousand cores for each cable.The length of these cables are more than 4 kilomaters. So it is necessary to keep pressure for these cable charged with air.To judge whether cable is damaged, maintainers need measure the pressure of each cable.Because of the coverage area of cable network, it is a hard work to measure pressure by mannual.To relieve to work payload of maintainers and promote the efficiency, kinds of remote measurement system for cable pressure are used by telecommunication company.To relieve to work payload of maintainers and promote the efficiency, kinds of remote measurement system for cable pressure are used by telecommunication company.With this kind of equipment, the cable pressure of several hundred control points can be measured within several minutes.With this kind of equipment, the cable pressure of several hundred control points can be measured within several minutes.By this way, not only the status of pressure can be under of control in time, but also distribution curve of the pressure can be drawn to judge the location of gas-leaking.If the console is added for the remote measurement equipment and digital/analog convertion circuit is configured, distribution curve can be displayed on the screen directly. It is so convenient for maintanence.So the remote measurement equipment of cable pressue is developed in our company to relieve the work payload of maintainers.The solution scheme, constitution and characteristics of gas filled cable barometric pressure telemetry system are described detailedly in the thesis. A multi-channels data acquisition system and pressure transmitter are designed based on the single chip MCS-51 of intel and MC68HC705 of motolora as a core. The data is transmitted to computer by isolated RS-232 interface. The device is entirely isolated from computer at electric, which reinforces the stabilization and security of working on device. The gas filled cable barometric pressure telemetry system is composed of many basic modules such as pressure transmitter, data acquisition system and computer etc.The hardware of system is designed by modularization for satisfying the system requires.The system can achieve 64channels input of analog quantities, each channel can Parallel 127 pressure transmitter and pressure curve. Data acquisition system used from the main structure, and one pair of control panels and control panels from the control block 8.Data acquisition rate can reach 1 MHz with the resolution of 16 bit.Pressure transmitter is composed of microprocessor, pressure sensors, clock chip and gain amplifier device etc. 100uA~5mA DC output signal.The system can collect and record the data for a long time, and make the time collection with the condition of no monitoring. The acquisition data can be transmitted to PC by RS-232. The application software of PC based on the most powerful PowerBuilder Integrated development environment provides convenience for the operation with curves and number of multi-channel quantities display as well as memory function. The system is composed of flexible, and easy installation. So it is suitable for work in the DGT for data acquisition ,wave-form analysis and processing. |
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