SIEMENS SIMATIC S7 + WINCC

Boiler Trip Safety Interlock

The boiler control system will perform boiler protection (TRIP). This protection system is based on the steam pipe level measurement through the level transmitters and float-type level switch installed at the very low level point, which send signal to the controller. The output signals from the controller should act directly on the fan motors and bagasse feeders, suppressing the combustion and protecting the boiler.

• Create the following variables in the symbol table:

Name	Address	Type	Description	S7_m_c
TRIPLL	M1.1	Bool	Low Boiler Level Trip	True
SPTRIPLL	MD56	Real	SP Low Boiler Level Trip	True

• Insert activation logic of the boiler trip at a very low level in the MOTORS function, above the MT300 Forced Air Fan. The trip occurs when the boiler level reaches a value lower than the SPTRIPLL very low level setpoint or when the LSLL200 digital input operates.

• Insert the trip into the interlock of the following motors:

MT300 - Forced Air Fan

MT305 - Induced Draft Fan

MT301 - Bagasse Feeder nr. 1

MT302 - Bagasse Feeder nr. 2

MT303 - Bagasse Feeder nr. 3

MT304 - Bagasse Feeder nr. 4

• Compile AS and OS.

• Create front for Boiler trip in the Controles.pdl.

• Insert boiler trip in the alarm list.