Shown below is the Main Screen of the PLC:
This shows a summary of the current operating state.

Screen Selection:
The buttons at the bottom edge of the screen navigate among the different screens. The option to return to the main screen is always given in the lower right corner. Some screens will only be reached if certain options are selected on the master configure screen. Dashed lines indicate these paths.

Alarm Log:
A history of the last 30 alarms is kept on this screen. The name of the alarm, as well as the time and date that it occurred, is recorded here. A counter is kept of recorded alarms and warnings. The value on this counter is displayed on the main screen alarm Log Button. This counter goes up every time something is recorded.

List of Alarm Codes:
Once our control system is installed with a telephone line, the following table of numbers relates the numeric codes indicated on the pager with the shutdown reason listed on the alarm log.


Power Failure


Low Water Cutout


Over Pressure Cutout


Safety Trip (aux)


Id Failure


Stack Motor Shutdown


Overfire Fan Failure


Underfire Fan Fail


Low Draft Shutdown


Low Temp Shutdown


Infeed Auger Failure


Runaway Fuel Auger


Low Fuel Shutdown


Supply Auger Failure


Fuel System Fault


Rotary Airlock Jam

Fuel Edit:
There are four (4) possible selectable fuels. The Low and High settings of the fuel to be burned and corresponding air required to burn the specified fuel are entered and will throttle between 0% and 100% throttle based on the boiler steam pressure and process demand.

Fuel Edit Acceleration Limits:
The throttle acceleration allowed can be limited based on the current combustion chamber temperature. This allows for rapid responses when the system is up to temperature or with controlled and gentle changes made when the firebox is colder. This limit will show on the pressure control screen as “rise limit”.
Note that there are different settings for each of the four available fuels. A PID loop will make the necessary system throttle changes based upon the steam pressure in the boiler.

Oxygen Control:
Control of the overfire fan to regulate oxygen content is automatic whenever the overfire fan is on.