Abstract:
A parallel port based remote data acquisition and process control system was built without on board
RAM and programmable timer to test the effect on the performance when processing real-time data
on a network environment. The controlling software was developed using Delphi and Assembler
languages to achieve high speeds. The developed software use TCP/IP protocol for network
operations.
It was found that the overall performance depends primarily on the parallel port. For different types
of motherboards, the speed of the data transfer varied between 460 Kbps and 890 Kbps. A
minimum deviation was observed when there were no processor-bounded applications running in
the system concurrently. The port speed did not depend on the processor type or the processor
speeds.
For the network transfer tests, client-server architecture was used. In order to increase the
throughput, data compression (Zip method) was used. A data stream of 4.5 Kb (sampled data
packet of 1500 byte) could be reduced to a 427±27 bytes with this technique. The compression and
de-compression time was negligible compared to the computer/network speeds. The client was able
to communicate with the server at an approximate speed of 1.3 Kbps on a network with fiber optic
backbone, which has a connection speed of 10 Mbps.
