We are from a petrochemical company. WE have conventioal relay logic in interlock circuit. We want to replaced it by PLC. How we move? Do we have to prepare flow diagram for this interlock. If yes how we prepare? Give with some example. What is Burner Management System?

 

Sanjib, First of all you should figure out if any of your interlocks are critical for safety in which case you might need a specialized PLC (browse for Safety Instrumented Systems). If it's only simple logic you might be able to enter it directly into the PLC from the ladder diagram.

We use a few simple documents to convey to the system configurator how the logic must work. "Cause & Effect" to convey logic "Alarm & Trip" to describe alarm & trip setpoints "Process and Instrumentation Diagram" to describe the process. A burner management system incorporates flame monitoring and a purge sequence before starting the burner. They usually require special approval from the boiler authorities, you probably have something like that already if you have a burner or boiler. Perhaps describe your process a little more with some details on your existing control system so that others can help you better.

Regards
Roy