Data Instruments, Inc.

Daniel R Weber

Andrew Dexter Baker

Orville E Bean

Raymond C Webb

A transducer system is provided including an inductive linear displacement transducer connected to a temperature-compensating signal processor. The signal processor includes (a) an amplitude-variable, frequency-stable device providing a modulated D.C. current through the transducer, (b) a temperature-sensitive element connected in series between the transducer and the current-providing device such that it is subjected to substantially the same temperature as the transducer, and (c) a signal processing circuit coupled to the temperature-sensitive element. The temperature-sensitive element has a high temperature coefficient so that temperature changes have a substantial effect on the DC offset of the signal coming from the temperature-sensitive element, and a low dynamic resistance so that temperature changes have substantially no effect on the amplitude of the signal coming from the temperature-sensitive element. The signal processing circuit (1) detects changes in the DC offset of the signal coming from the temperature-sensitive element and generates a signal used as the input to the current-providing device to adjust the amplitude of the modulation of the current in compensation for changes in the amplitude of the signal coming from the transducer due to temperature changes; and (2) monitors the amplitude component of the signal coming from the temperature-sensitive element and provides an output signal reflective of the linear displacement of an object connected to the transducer.

Inductive linear displacement transducer and temperature-compensating

An optical detection system of the sort adapted to enable and/or disable the operation of an associated industrial machine when an appropriate intrusion is detected. The optical intrusion detection system is adapted to have a variable sensitivity, whereby it can be set to respond to the intrusion of an object of a first size during one phase of operation of said machine and to an object of a second size during another phase of the operation of said machine.

Intrusion detection system for operating industrial machines with

A novel press load monitoring system for a variable speed press which is capable of automatically adjusting the measured load level of the press so as to compensate for strain in the press frame produced by mechanical vibrations occurring as the speed of the press is varied.

Speed-compensated press load monitoring system

The invention is an improvement over the system disclosed in U.S. Pat. No. 3,805,061 for detecting intrusion of a selected area by an object and for operating or terminating operation of an associated apparatus when such intrusion occurs. It consists of improved transmitter and receiver units. The transmitter comprises a plurality of radiant energy sources that are strobed sequentially and repetitively by a clocked counter. The receiver has a plurality of radiant energy detectors, means for enabling the detectors sequentially and in synchronism with the strobing of the radiant energy sources, dual control relay means for operating or terminating operation of an associated apparatus, and cross coupled control circuits for causing the relay means to change states if a radiant energy detector fails to detect a radiant energy beam while it is enabled. The receiver's control circuits include pulse detection means for determining if the radiant energy detectors produce pulses in response to incident radiant energy beams, and means for accomplishing at least one of the following: (a) deactivating the relay means if a relay driver has a fault, (b) deactivating the relay means if a pair of relay contacts are stuck closed, (c) terminating flow of current to some or all of the solid state components such as counters, switches, etc. of the receiver when a fault occurs in a relay control circuit, and (d) providing visual indications of the state of the relays.

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Groton, MA, United States of America

Daniel R Weber