Set point controller

Claim 2

A control system comprising a plurality of analog control devices each responding to an analog control signal comprising: a digital computer responsive to inputs from said system, said computer producing a plurality of set point signals including a variable pulse width signal representative of a change in at least one of said inputs, and continuous raise or lower signals controlling the direction of control of each of the devices and persisting until a predetermined, desired adjustment is accomplished; a plurality of set point controllers, each of said set point controllers being responsive to one of said set point signals, each of said set point controllers including: an incremental step motor comprising a plurality of windings and a rotor, selective energization of the windings of said motor causing incremental rotation of the rotor of said motor; a potentiometer including a rotatable shaft coupled to said motor for producing an analog control signal as an output in response to rotation of the rotor of said motor; two bi-stable flip-flops each having two outputs and a set and a reset input, one output of each flip-flop being connected to one side of each of the windings of said motor, the other output of each flip-flop being connected to the other side of each of said motor windings, said variable pulse width signal being applied to energize said flip-flops only during the time duration of said pulse, each of said flip-flops being of the toggle type having two enable inputs and a toggle input, a source of clock pulses, the source in each set point controller being synchronized to the frequency of the same local line power, said source of clock pulses being applied to the toggle inputs of said flip-flops, and two AND gates connected through an OR gate to each of the set and reset inputs of each flip-flop, the output of said flipflops being connected to the inputs of said AND gates to determine the switching sequence when said raise signal is present and in a second switching sequence when said lower signal is present, whereby the same pulse width signal produces the same analog control signal in different controllers because of the synchronization of each controller to the same line power frequency and because the same logic circuitry is used in both a raise and a lower sequence.

Claim 3

A control system comprising a plurality of analog control devices each responding to an analog control signal: a digital computer responsive to inputs from said system, said computer producing a plurality of set point signals including a variable pulse width signal representative of a change in at least one of said inputs, and continuous raise or lower signals controlling the direction of control of each of said control devices and persisting until a predetermined, desired adjustment is accomplished; a plurality of set point controllers, each of said set point controllers being responsive to one of said set point signals, each of said set point controllers including: an incremental step motor having a permanent magnet rotor, a permanent magnet stator and four motor windings, selective energization of said windings causing incremental rotation of a motor shaft connected to said rotor, a multiple turn potentiometer having a potentiometer shaft which positions a contact on a resistor to produce said analog control signal as an output in response to rotatioN of said potentiometer shaft, a direct fixed coupling without intervening gears and disposed between said motor shaft and said potentiometer shaft so that said potentiometer shaft rotates one revolution for each revolution of said motor shaft, idler gear means connected for rotation with said potentiometer shaft, and a manual adjustment knob having engaging means at one end thereof for selectively engaging said idler gear means to allow manual adjustment of said potentiometer, two bistable flip-flops each having two outputs and a set and reset input, one output of each flip-flop being connected to one side of each of said motor windings, the other output of each flip-flop being connected to the other side of each of said motor windings, said variable pulse width signal being applied to energize said flip-flops only during the time duration of said pulse, each of said flip-flops being of the toggle type having two enable inputs and a toggle input, a source of clock pulses, the source in each set point controller being synchronized to the frequency of the same local line power, said source of clock pulses being applied to the toggle inputs of said flip-flops, and two AND gates connect through an OR gate to each of the set and reset inputs of each flip-flop, the outputs of said flip-flops being connected to the inputs of said AND gates to determine the switching sequence when said raise signal is present and in a second switching sequence when said lower signal is present, whereby the same pulse width signal produces the same analog control signal in different controllers because of the synchronization of each controller to the same line power frequency and because the same logic circuitry is used in both a raise and a lower sequence.

Claim 4

A control system comprising a plurality of analog control devices each responding to an analog control signal: a digital computer responsive to inputs from said system, said computer producing a plurality of set point signals including a variable pulse width signal representative of a change in at least one of said inputs, and continuous raise or lower signals controlling the direction of control of each of said control devices and persisting until a predetermined, desired adjustment is accomplished; a plurality of set point controllers, each of said set point controllers being responsive to one of said set point signals, each of said set point controllers including: an incremental step motor having a permanent magnet rotor, a permanent magnet stator and four motor windings, selective energization of said windings causing incremental rotation of a motor shaft connected to said rotor, a multiple turn potentiometer having a potentiometer shaft which positions a contact on a resistor to produce said analog control signal as an output in response to rotatioN of said potentiometer shaft, a direct fixed coupling without intervening gears and disposed between said motor shaft and said potentiometer shaft so that said potentiometer shaft rotates one revolution for each revolution of said motor shaft, idler gear means connected for rotation with said potentiometer shaft, and a manual adjustment knob having engaging means at one end thereof for selectively engaging said idler gear means to allow manual adjustment of said potentiometer, two bistable flip-flops each having two outputs and a set and reset input, one output of each flip-flop being connected to one side of each of said motor windings, the other output of each flip-flop being connected to the other side of each of said motor windings, said variable pulse width signal being applied to energize said flip-flops only during the time duration of said pulse, each of said flip-flops being of the toggle type having two enable inputs and a toggle input, a source of clock pulses, the source in each set point controller being synchronized to the frequency of the same local line power, said source of clock pulses being applied to the toggle inputs of said flip-flops, and two AND gates connect through an OR gate to each of the set and reset inputs of each flip-flop, the outputs of said flip-flops being connected to the inputs of said AND gates to determine the switching sequence when said raise signal is present and in a second switching sequence when said lower signal is present, whereby the same pulse width signal produces the same analog control signal in different controllers because of the synchronization of each controller to the same line power frequency and because the same logic circuitry is used in both a raise and a lower sequence.