Abstract: An apparatus for controlling an electrical appliance coupled with an output terminus and configured to operate in response to an alternating input signal, such as input AC power. The apparatus comprises a reference signal generator for receiving the input signal and generating a reference signal (either V.sub.RAMP or V.sub.CONTROL) in response to the input signal, and a control circuit for controlling connection of the input signal to the output terminus in response to the reference signal and to a user-defined set-point signal. The control circuit is coupled with the reference signal generator and with a set-point terminal. The set-point terminal receives the set-point signal and the control circuit controls connection of the input signal with the output terminus in response to a predetermined relationship between the reference signal and the set-point signal; the apparatus is capable of generating a modified periodically interrupted AC power output based on an AC power input.

Abstract: An instrumentation interface circuit controlled by a microprocessor of a data acquisition system enables identification of the type of input/output devices that are connected to its inputs through a systematic analysis of the characteristics of the connected devices, the systematic analysis including monitoring the current through and the voltage across the devices as different drive signals are applied to the connected devices, the interface circuit including a conditioning circuit having a drive circuit which is controlled by the microprocessor for providing the drive signals, a current sensing circuit for sensing the load current flowing through the connected device, a voltage sensing circuit for sensing the voltage across the connected device, and a switchable feedback circuit which is controlled by the microprocessor to selectively feed back the load current or the sensed voltage to the input of the drive circuit to establish the drive signals for the connected device.

Abstract: A signal isolation apparatus has a first transformer with a primary winding tap receiving an input signal and another primary winding tap receiving a first oscillating signal. A second transformer has a primary winding tap receiving the input signal and another primary winding tap receiving a second oscillating signal. The second oscillating signal is out of phase (typically 180 degrees out of phase) with the first oscillating signal. A rectifier electrically connected between a first secondary winding tap of the first transformer and a first secondary winding tap of the second transformer has a high output terminal and a low output terminal, the low output terminal being referenced to a second secondary winding of the first and second transformers. A signal across the high and low output terminals is an output signal galvanically isolated from the input signal with the same electrical characteristics as the input signal.

Abstract: An improved control system utilizing infrared communication channels for remote station control is provided. A central base controller communicates with one or more channels of sub-networks through one or more field interface controllers. Each field interface controller utilizes a dedicated base infrared transceiver for transmitting envelopes of definable duration at a preselected infrared oscillation frequency. At least one remote station receives said transmitted infrared signals at an infrared transceiver tuned to said oscillation frequency. Associated devices at the remote station decode the information from said infrared transmission or issue instructions and information to an associated input/output device. Communication over the infrared channel between the base and the remote stations utilizes a unique pulse position protocol. An initiating clear pulse begins all communications. The remote station responds to the time-location of ensuing pulses following the initiating pulse.

Abstract: An arrangement monitors the values at sensors such as temperature sensors which each generate a voltage value related to the particular sensor temperature. The arrangement produces a digital value representative of the temperature at each sensor, wherein errors caused by fluctuations in the temperature of the arrangement circuitry and aging are reduced toward zero. The arrangement corrects for errors for a wide range of combinations of sensor temperatures and temperature fluctuation in the circuitry of the arrangement. The arrangement includes separate channel circuitry associated with each sensor and temperature independent references associated with each sensor type. Generally, to provide error correction, the arrangement uses stored comparison values to correct for channel-to-channel circuitry differences and stored values associated with the independent references to correct for temperature fluctuation and aging of the arrangement.

Abstract: A method for communicating binary data using modified frequency shift keying techniques generally includes the steps of selecting a first bit count representative of a first untranslated frequency denoting a data signal at a first logic state, selecting a second bit count representative of a second untranslated frequency denoting a data signal at a second logic state and computing a mean bit count intermediate the first and second bit counts.A signal is detected which has a first component at a first translated frequency and a second component at a second translated frequency and defines a first interval of time having boundaries identifiable as T0 and T1, a second interval of time having boundaries identifiable as T1 and T2, a third interval of time having boundaries identifiable as T2 and T3 and a fourth interval of time having boundaries identifiable as T3 and T4.

Abstract: A solid state motor control circuit for controlling the operation of a servo motor comprises a comparator circuit including a differential amplifier having its inputs connected across terminals of the motor and having its output connected to a drive circuit the output of which is connected to a supply terminal of the motor. A reference circuit maintains a reference terminal of the motor at a reference level, and in the absence of a command signal, the differential amplifier and drive circuit maintain the voltage at the motor supply terminal at the reference level. A control switch enabled by the command signal applies a control signal to an input of the differential amplifier, and the differential amplifier responsively enables the drive circuit to raise or lower the potential at the motor supply terminal relative to the reference level, thereby energizing the motor.