Abstract: The apparatus for driving and monitoring a lamp includes a main drive circuit, a backup drive circuit, a monitoring circuit, all connected to a controller. If the controller determines that the main drive circuit cannot energize the lamp, the backup circuit is enabled to energize the lamp. For purposes of energizing the lamp, the lamp is connectable to one of two electrical ground references. If one of the ground references becomes open circuited from the remainder of the circuitry, then the lamp is energized through the other ground reference.

Abstract: A microcomputer based system is designed to accurately detect the amount of previously applied torque to a fastener by way of a retorque test in which torque is subsequently applied to the fastener in the tightening direction until breakaway occurs. As torque is subsequently applied to the fastener a microprocessor operates to sample an analog torque input signal and convert it into discrete digital samples. These digital samples are stored in sequential memory locations during the tightening process. The microprocessor stops generating any further samples once a window containing the values of interest has been defined in memory. Then, the microprocessor examines the stored window samples in more detail to detect the sample value associated with the amount of torque previously applied to the fastener.

Abstract: The amount of previously applied torque to a fastener is measured by analyzing a series of digital torque values generated during a test of the fastener.