Modeling packet delay distributions in an industrial telemetry system

This paper presents some observations of data packet delaying in a real productive industrial telemetry system. It introduces the statistical analysis of measured Round Trip Time (RTT) values of used Internet Control Management Protocol (ICMP) and User Datagram Protocol (UDP) packets usually used in such applications. Scheduled ICMP delay measurements are simple to implement, while the UDP packets delay measurements need making modifications in the industrial transmission protocol implementation used in the whole telemetry system. A comparison between these two cases has been carried out. The delay measurements were carried out in all possible scenarios between each significant nodes of the distributed telemetry system. The proposed research topic is a part of a realized global distributed wind turbine monitoring system project. A comparison between obtained and required quality of service of General Packet Radio Service (GPRS) packet data transmission in these industrial applications was carried out. The paper introduces a simple method of evaluation of the theoretical probability density functions in form of histograms in all investigated scenarios. These models can give some interesting results to make the data transmission in the distributed telemetry system more effective and “intelligent”.