Controlling the G2 instrument: The instrument has two control knobs that operate combination rotary and push button switches. The top knob in general controls screen selection while the bottom knob controls items within the given screen. Each screen assigns its own functional needs to the controls that may change depending on context. A screen may also label the controls with guidance information like “Push to exit”.

The Bar-Graph Display Screen: The Exhaust Gas Temperature is displayed in white bar graph form and is interpreted much like a conventional mercury thermometer. The higher the bar, the higher the temperature.

The cylinder head temperature is displayed in green single bar format. During normal operation it shows as a green illuminated bar in the lower half of the bar column. Since EGT is normally higher than CHT, the green bar which represents CHT is on top of the white illuminated EGT bar and stands out clearly. However, when the engine is shutdown, the EGT quickly drops to zero and the cylinders remain warm for sometime.

The G2 provides a reliable indication of cylinder head temperature even with the engine shut down. Should an EGT probe fail, the entire EGT column for that cylinder will go blank, and the numeric indication will show --- that is dashes, but the CHT bar will still remain green. The failure of one probe will not affect the display of any other probe.

An Easy Upgrade: A key requirement of the G2 design was compatibility with previous GEM’s. We strive to never leave our loyal customers behind. Packing all the functionality of the G2 in package half the size of the original GEM took us to the limit of our patience many times but it was worth it. Fortunately its amazingly compact circuits will be built by robotic machines because most of the parts are too small to handle and too difficult to be seen by eye. Products like the modern cell phone have driven the electronic assembly technology we use a long way.