Abstract: A measuring device includes a microprocessor controller programmed for performing any of a plurality of mathematical functions on a measured value of a parameter under test. The measuring device is provided with two displays, for displaying to a user both the parameter value and its mathematical function. Annunciators are provided to identify the displayed function of the parameter. Thus, together with the measured parameter value, offset, scaling, peak-to-peak values, or the uncertainty of a reading may be displayed, as well as statistical functions of the measurement, including an average, standard deviation, median or mode of the parameter under test. The methematical function display is updated concurrently with the display of the measured parameter value.

Abstract: A simplified master controller or outguard circuit monitors and controls a plurality of separate slave, or inguard, circuits. Only a single watchdog circuit is provided on the outguard arrangement, with simplified timers being provided on each inguard arrangement to generate a direct hardware reset signal for local microprocessors in the inguard circuits using existing serial communication lines. A break signal generated by the watchdog in the outguard circuit is detected and, without interpretation, converted to the reset signal for the inguard circuit in synchronism with operation of the outguard circuit.