Communicating With Older Industry Systems

Considering the advantages of modern computer communication technologies

, especially Ethernet, it is in place to ask how to utilize them in an industrial system (by the industrial system we can understand a control system, PLC, smart controller or measurement instrument). When building a new system, the answer is evident, simply to buy one with already implemented Ethernet interface.

However, in case of already installed system (or when the manufacturer doesnt offer an Ethernet variant) it is necessary to utilize some alternative solution. When looking for such solution it is desirable at first to ask, what effect should the Ethernet bring to the user? Then according to the desired effect it is possible to choose a proper solution. Basically, the expected effect is to get a remote access to the system, either over local intranet or over Internet.

When examining existing industrial systems one can find that the common feature of majority of the systems is presence of some kind of serial interface (RS- 232/ 422/ 485), regardless of the used communication protocol. Considering this, the obvious way of connecting any already installed industrial system to the local network is to use some kind of