The second target is the temperature or pressure of the boiler, monitored by the combustion system. At all times, the exact amount of fuel and air are fired to achieve the target value and at no time, irrespective of load change, is this target exceeded or fallen short of. Mechanical systems that have traditionally involved cams and linkages to characterise the fuel/air ratio have made this accuracy impossible. At most times, the accuracy of the fuel input response to the monitored temperature/pressure has meant that the target value set by the operator has been significantly exceeded or fallen short of.

The Micro Modulation system provides an easily programmable and flexible means of optimising combustion quality throughout the load requirement range of the boiler/burner, whilst ensuring that temperature is accurate to within 1°C/2°F and pressure to within 1.5psi/0.1 bar. The maximum error in degrees angular rotation between the servomotors at any position in the load range is 0.1°.

At the heart of the system is the control module containing the microprocessor and power supply. The display panel features touch sensitive keypad data entry, VGA/LCD display and LED status indicators. The MM system displays the positioning data for up to six individually controlled channels. The status function will display the “required” and “actual” set point, burner firing rate % and the selected fuel. The MM can be calibrated to display instantaneous and totaled fuel flow measurements. A voltage dividing system monitors each channel’s position, enabling digitised position information to be encoded into the control module’s memory. The relative positioning of the channels are constantly checked by the system at the rate of 50 times per second.

The burner control system achieves “Locked On” near stoichiometric air fuel mixing throughout the fuel input range of the boiler while maintaining exact temperature or pressure target values. The load control incorporates full user variable P.I.D. control.