10-03-2012, 04:04 PM
PLC BASED PROTECTION AND INTERLOCKS SYNOPSIS
A programmable logic controller (PLC) is an industrially hardened computer based
unit that performs discrete or con tenuous control function in a variety of processing
plant and factory environment. PLC consists of CPU, input device, output device and
Programming device. PLC replaces relays, timers, counters and sequencers.
Our project concerns with PLC based protection and interlocks for
1. Boiler feed pumps.
2. Mill and feeder interlocks.
3. Slag conveyor monitoring system.
4. Debris filter.
In boiler feed pump, the relays are used for starting and tripping of feed pump with
satisfying the specified condition. Even when one condition is found to be failed it
leads to the failure of the whole system. But we can overcome these limitations when
the PLC is used.
Similarly in mill and feeder interlocks dampers are generally used. To overcome
the dampers PLC is used. Also for the same purpose PLC is used in slag conveyor
monitoring systems.
