Abstract: An integrated low NO.sub.x tangential firing system (12) that is particularly suited for use with pulverized solid fuel-fired furnaces (10), and a method of operating a pulverized solid fuel-fired furnace (10) equipped with an integrated low NO.sub.x tangential firing system (12). The integrated low NO.sub.x tangential firing system (12) when so employed with a pulverized solid fuel-fired furnace (10) is capable of limiting NO.sub.x emissions therefrom to less than 0.15 lb./10.sup. 6 BTU, while yet maintaining carbon-in-flyash to less than 5% and CO emissions to less than 50 ppm. The integrated low NO.sub.x tangential firing system (12) includes pulverized solid fuel supply means (62), flame attachment pulverized solid fuel nozzle tips (60), concentric firing nozzles, close-coupled overfire air (98,100), and multi-staged separate overfire air (104,106).

Abstract: An ATE system uses a single digital to analog converter and a single analog line for defining the reference voltage levels of a plurality of pin drivers and pin sensors. An advantage of using a single DAC is that the number of components for routing the reference voltage signals is reduced. Digital values for each high and low reference voltage level for each pin driver and each pin sensor are stored in memory. Such memory is addressed sequentially reference value by reference value, converted to analog format and routed along one common analog wire to a plurality of sample and hold circuits. The plurality of sample and hold circuits receive a pin driver/sensor address and the common analog signal. The address enables one of the plurality of sample and hold circuits and selects only one output line of the enabled sample and hold circuit. Such output line is coupled to a given reference terminal (e.g., reference high or reference low) of a given pin driver or a given pin sensor.