Abstract: A system is disclosed for determining the energy transfer across a heat exchanger having an upstream side and a downstream side and mounted within a conduit through which fluid flows, the system including an ultrasonic transmitter for transmitting ultrasonic waves through the conduit on the upstream and downstream sides of the heat exchanger, an ultrasonic receiver for receiving the ultrasonic waves on the upstream and downstream sides of the heat exchanger, the receiver providing signals indicative of the temperature difference between the fluid upstream and downstream of the heat exchanger and the velocity of fluid flow through the conduit and a processor connected to the receiver for determining energy transfer between the heat exchanger and the fluid based upon the signals indicative of the temperature difference and the velocity.

Abstract: A system for positioning the output shaft of a motor is disclosed having a set of terminals for receiving a predetermined count representing a desired position for the output shaft, a counter having first and second inputs, the first input being connected to the set of terminals, a count generator associated with the output shaft and connected to the second input of the counter for supplying to the counter counts dependent upon the rotation of the output shaft, and a switch connected to the motor and to the counter for energizing the motor when the counter receives a predetermined count representing the new desired position and for de-energizing the motor when the count generator supplies a number of counts equal to the predetermined counts.

Abstract: A control system for controlling a stepping motor having a predetermined number of steps between its start position and its fully extended position having a stepper motor, an initiate circuit for supplying pulses to the stepping motor to drive the stepping motor to its initial or start position, and a positioning control for stepping the stepping motor from its start position to a desired position.