Sigma Instruments, Inc.

John O Morin

Thomas E Beling

Florian F Yanikoski

Joseph R Mini

In the system disclosed a driving circuit repeatedly scans along a plurality of aligned electrodes in an enclosure filled with ionizable gas, by sequentially grounding the aligned electrodes and repeating the process cyclically. Within each cycle, a pulse width modulator energizes an anode opposite the electrodes for a period of time corresponding to an input value. Sequential glow discharges thus occur between the cathodes and the anode over a portion of the anode length. The discharges occur with sufficient rapidity so that they are observed as an illuminated portion of a bar formed by the electrodes. A second set of electrodes is scanned and an opposing anode energized to produce two illuminated bands separated from each other. Desired upper and lower set point limits for the input quantity determine the lengths of the bands and the separation between them. According to one embodiment, the separate bands are initiated from opposite ends of the bar formed by the electrode alignment with suitable reset cathodes. The driver forms one band from one end of the aligned electrodes and the other band from the other end of the aligned electrodes. According to another embodiment the space between the bands is formed by decreasing the anode current only enough to reduce the glow.

Systems for displaying analog values

Knitting-machine guide bars, which carry columns of guides through and then along a row of knitting needles and are moved longitudinally along the row on the basis of the content of a programmable read-only memory. Stepping motors which respond to the memory rotate pinions in directions and numbers of steps determined by the memory. Racks engaging the pinions articulate respective adjustable-leverage levers which reciprocate the separate guide bars longitudinally along the row. Respective springs press each rack against each pinion transverse to the rack length so as to eliminate slack. Longitudinal movement of the bars is synchronized with their transverse movements through the needle row by sensing when the guides clear the front of the needles and producing a synchronizing pulse that gates appropriate signals from memory buffers to the motors; and producing a synchronizing pulse on a separate channel when the guides are clear of the rear of the needles. Braking means brake the motors with torques of about 50% of the maximum motor torques.

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Bedford, MA, United States of America

John O Morin