Addressable Vs Conventional Fire & Gas Systems

[adjalabi]

We're trying to compare Industrial Fire and Gas Systems, PLC based, for the installation in a process facility (oil & Gas) as part of our conceptual design. We'd like to propose an addressable system over a conventional custom designed zone interface system and I'd like some input from anybody knowledgeable in the industry to help make a stronger case. What are some of the problems poeple generally experience with lets say a Siemens (Pyrotronics) Ceberus 3 system (considered conventional now) and how do they stack up to some of the newer dual redundant addressable systems such as those offered by Det-tronics?

 

[JLSeagull]

My preference is to bring the individual detectors into the same high reliability type safety system used for emergency shutdown. I prefer 4-20 mA signals. This reduces the number of software packages that the engineers must know and allows for easy expandability.

The addressable detectors may be less costly. However you must bring both the serial communications link and 24 Vdc power to each detector. Voltage drop can be an issue. Expansion requires breaking the serial link. Although unclear, you might also have to change addresses for an expansion. These redundant systems handle a limited number of detectors and they lack peer-to-peer communications to integrate each controller with each other. The hot switchover time seems long compared to the ESD system. Both the logic solver and graphic software are custom.

I would prefer a system that uses something like Wonderware so that you could use any of thousands of contract programmers for the graphics. I would require IEC 61131-3 compliant PLC programming software.