Control.com - Nerds in Control

We are doing a project for a chemical plant. In this plant STAHL remote IO is used. There are 50 Romote IO cabinets. We want to get a solution so that Profibus NW can be used in ring topolgy (in a redundant way). The distance from the host of this remote IO is approx 300 m.

You can get a redundant profibus link using a ring topology by using fiber optic converters and a fiber backbone for the profibus network. The fiber modems automatically detect a break or fault in the fiber ring and send the data "round the other way" (for want of a better explanation). In fact, if your profibus is 300m long I would expect this to be much easier setup to install and troubleshoot than a copper based network.

Phoenix Contact amongst others make suitable modems.

www[.]lymac.co.nz

Hello Partha;
Here is a FAQ from Siemens explaining their solution for Profibus-DP redundant ring topology:
http://support.automation.siemens.com/WW/view/en/19758281

If more information is required, click o the New Search link on the same page, and do a search on any product number you require.

Hoep this helps,
Daniel Chartier

Ring topology using CONVERTERS is not quite redundancy.

The converter is not redundant. So the converter itself is a single point of failure.

The devices (PLC, remote-I/O, drive...) only have a single communication port so it is also a single point of failure.

The wire between the converter and the device is single (albeit short) and is a single point of failure.

In a truly redundant system each device has two communication ports, so if one port fails the other port can still be used. "Splitting T" is not required.

Cheers,
Jonas