Design Of Chiller's Remote Monitoring System Based On GPRS

The physical construction, refrigerant system and control system of chiller are morecomplex than those of household air condition. According to the feedback from the marketing,the failure rate of chiller is higher than household air condition also. The engineers of thechiller manufacturer can't support all the chillers all the time. For the lack of serviceengineers and the difference of the technical ability among these service engineers, not all thechillers can be repaired in time. Also the time spending and the misjudgement rate can notsatisfy the customers or the chiller manufacturer. If the design engineers can get theinformation of the customer's chiller in time, especially for the chiller's information aroundthe failure occurred, it will be much helpful for field test in the chiller design, supporting thefield troubles and resolving the difficult failures. Also it can reduce the developing andsustaining cost and raise the customers'satisfaction rate.This thesis shows a communications architecture based on the GPRS service of existingGSM network of China Mobile for the chiller's remote monitoring and control. With thissystem, the PC in the chiller manufacturer's office which located in Chinese mainland andlink to Internet with the ISP of China Telecom can monitor and control any chiller in anyposition with the network of China Mobile in the mainland of China.With the remote monitoring and control system consists of the remote communicationinterface of Modbus protocol and RS-485 which provided by the chiller, local S3C2440A32-bit embedded system, GPRS DTU, and PC, we success to monitor the chiller, save theinformation and status of it, and we can control the chiller also. When the TCP communication failure between the chiller and the PC occurs, this system can backup theinformation of the chiller in the local S3C2440A 32-bit embedded system. Also it supports thesimple querying for the data saved. In this research, this author select the suitablecommunications architecture and final design according to the requirements of the chiller'smanufacturer, the influence to the communication technology from the chiller andcomparison between the payment and gains. Also this thesis try to do some researech tooptimize the waveforme on the RS-485 bus with software methods.According to the feedback of internal test and field trial, it works well and can achieve tothe requirements of the remote monitoring and control system for chiller's repairing andremote diagnosis. For some other systems similar, it has the larger applied range with lowcost and good real-time performance.