The Foxboro Company

Allan L Flanagan

David A Richardson

Richard O Driscoll

Reading values, setting values and setting configuration options within a complex programmable apparatus is simplified, by chaining all user interaction points into a single path, cross linking portions of the main path into subpaths and providing keys that step the user according to his selection along the main path, along the subpaths, and between the subpaths. A two part display indicating the general and specific positions clarify the locations and the options available.

Method and apparatus for configuring a controller

Reading values, setting values and setting configuration options within a complex programmable controller is simplified, by chaining all user interaction points into a single path, cross linking portions of the main path into subpaths and providing keys that step the user according to his selection along the main path, along the subpaths, and between the subpaths. A two part display indicating the general and specific positions clarify the locations and the options available.

A compact ribbon-indicator and chart-recorder instrument for use in process control systems adapted to indicate and simultaneously record the values of up to three independent process variables. The motive power for each pen/indicator drive system is supplied from a corresponding relatively high-speed stepping motor. Each such motor is servo-controlled by a feedback circuit including a potentiometer coupled to the pen drive cable for developing a d-c feedback signal to be compared with the d-c measurement signal. The system is arranged to actuate the motor immediately upon development of a deviation signal outside of a fixed dead-band, but the extent of initial motor movement is limited to a pre-set small amount (preferably one step). If the deviation signal still is outside of the dead-band after a predetermined period of time, a clock pulse oscillator is turned on to actuate the motor at a relatively rapid rate until the deviation signal returns to the dead-band. The instrument also includes special limit circuitry for preventing motor activity when the pen has been driven to either end of its full-scale stroke. An optional addition is an alarm system which makes it possible to adjust the alarm set-point while observing its value on the indicator scale at the front panel, thereby avoiding need for a precision calibrated set-point potentiometer.

Industrial process indicating/recording apparatus using stepping motor

A deviation meter, responding to a deviation signal, is mounted on a turntable which rotates in response to a set point adjustment. Rotation of the turntable maintains the null position of the deviation meter pointer at a scale position corresponding to a set point value, so that a direct readout of the actual measurement value is provided.

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Attleboro, MA, United States of America

Allan L Flanagan