Water Level Control of Boiler Drum Using One IEC61131-3-Based DCS

The drum water level is a very important parameter of the boilers in power plants. One method, using FBD language in IEC61131-3 to implement the water level control system on the platform of the 893-DCS, is probed. On the basis of the description of the IEC61131-3-based DCS and the analysis of the dynamic process of the boiler drum water level, the two-level-tracking technology of the no-disturbance switch and the dead band approach in the control system are presented and discussed in detail. The good applications have proved that this water level control system is one reliable and open system.