Abstract: A mounting for a solderable component module (SCM.TM.) interconnect includes an elongated trench or blind via for receiving an edge of the module. The interconnect may be adjusted to reduce the parasitic inductance associated with the connection of the SCM interconnect and the motherboard. Preferably, the design of the finger connectors associated with the SCM interconnect or other board module can be adjusted to reduce parasitic inductance. Alternatively, the capacitance associated with the SCM interconnect or motherboard may be adjusted. The SCM interconnect preferably includes finger connectors which have a rectangular shape. The finger connectors preferably have a shape wherein the length is greater than the width and have an enhanced thickness which reduces parasitic inductance. The finger connectors are spaced close together.

Abstract: A method and apparatus for providing multitasking of a plurality of requests queued as a list in a single task of an industrial controller, each request including one or more separate segments. State information relating to each request being minimal at the end of each segment. The method processing the requests on a round-robin basis, interrupting each request only at the end of each segment so as to minimize the memory required to store the state information.

Abstract: A method and apparatus to be used with an inverter based motor controller for determining current phase angles for the current on a single phase of a three phase AC motor from an inverter generated high frequency phase voltage sequence. The invention detects turn on delay periods and compares phase voltages during consecutive turn on delay periods to determine phase current zero crossing times which can be used along with phase voltage zero crossing times to derive current phase angle information.

Abstract: A method and apparatus for compensating for deviations in the alternating voltage produced by a PWM inverter. The necessary sequence in which inverter components must be triggered results in voltage error pulses that accumulate over time and result in deviations from ideal voltage at motor terminals. By allowing the error pulses to continue and adjusting the trigger times to compensate for the error pulses, the effect of the error pulses is negated and the voltage deviations are eliminated.

Abstract: A method of operating an industrial control system converts relay ladder logic programs into flow type programs expressed as `logical gates` connected with `wires` representing variables. This formulation is converted to an efficient code structure in which changes in state of the variables are evaluated and only changes are propagated in evaluating program outputs. The net effect is many steps of evaluation in the control program are avoided during real-time operation of the program connected to controlled equipment.

Abstract: A controller for driving an AC motor includes a rectifying circuit, an inverting circuit coupled to the rectifying circuit via a DC bus, a control circuit for commanding operation of the inverting circuit, a logic circuit for directing operation of the control circuit in accordance with a predetermined control routine and a power supply circuit for powering the logic and drive circuitry. At least the rectifying circuit and the inverting circuit are supported on a power substrate module, while the control circuit is supported on a separate control circuit board. The control circuit board is mounted on and coupled to the power substrate module via conductors. Incoming AC power and control signals are transmitted to and controlled AC power is transmitted from the power substrate module via the conductors through the control circuit board. Separation of the circuitry between the power substrate module and the control circuit board permits significant reduction in the footprint of the controller.

Abstract: A multi-tasking industrial controller for real-time control of machinery and the like permits the use of both periodic and event driven tasks by establishing a hierarchy of both task types in the form of priorities that resolve conflicts between events of the same and different types. Each task may access a common "global" memory area to communicate information and timing with other tasks and so as to coordinate the overall industrial control process. Trouble-shooting of the task software is made possible by a hardware address monitor which may be programmed to identify access of a particular memory location or range by any task and to record information about the particular task causing that global memory access.

Abstract: A method and apparatus used with a motor controller for determining the average value of a voltage signal including at least two analog integrators that integrate the voltage signal during consecutive and alternating integration periods, a selector receiving each integrated value after an integration period and determining an average voltage value therefrom, and a discharger that sets each integrated value equal to zero after the value has been sampled, the apparatus and method providing a series of changing average voltage values during motor operation.

Abstract: A rigid-flex multilayer circuit board or laminated circuit board includes an insulated mounting area for a surface mount package. The mounting area is provided in a recess or portion of the circuit board where the circuit board is only a single flexible circuit board layer thick. The insulated mounting area is provided in a blind via in the multilayer circuit board. The insulating medium associated with the single flexible circuit board layer is less than 2.0 mils thick and includes polyimide. The single flexible circuit board layer provides a heat conductive yet highly electrically insulative mounting area for receiving a heat sink. The heat sink can be mounted on a side opposite the electrical device. The heat sink may be a standard heat sink or a copper coil directly soldered to the circuit board. The heat sink mounting area eliminates the need for bolts, nuts, brackets, and an additional insulating layer necessary to insulate power semiconductor components.

Abstract: A multilayer circuit board or laminated circuit board includes an insulated mounting area for a surface mount package. The mounting area is provided in a recess or portion of the circuit board where the circuit board is only a single layer thick. The insulated mounting area is provided in a blind via in the multilayer circuit board. The insulating medium associated with the single layer provides a heat conductive yet highly electrically insulative mounting area for a heat sink. The heat sink may be mounted on a side opposite the electrical device. The heat sink may be a standard heat sink or a copper coil directly soldered to the circuit board. The heat sink mounting advantageously eliminates the need for bolts, nuts, brackets, and an additional insulating layer necessary to insulate power semiconductor components.

Abstract: An improved method and apparatus for handling saturation conditions in the digital compensator of a control system. A clipping limiter is incorporated in the digital compensator for outputting both a limited signal to be sent to the actuator, and for outputting a clipping signal indicative of a difference between the input and the output of the clipping limiter. The clipping signal is delayed by one sample period, and fed back to the input to the compensator in order to provide a correct amount of compensation when the system is operating at or near saturation.

Abstract: The present invention provides a switching device incorporating a simple circuit capable of avoiding the flash-on of a transistor when a power supply is turned on and off thereby reducing the OFF delay time. The output circuit comprises a FET (145) having a drain and a source connected in series to a current line for supplying a current from a power supply (VD) to an output detector (load) (L), and a photocoupler (149) for applying a driving voltage across the gate and the source of the FET (145) according to the output of an internal circuit (151), a differentiation circuit comprising a capacitor (7) and resistors (5,9) is connected across the drain and the source of the FET (145), and second transistor (3) having a collector and an emitter connected to the gate and the soruce of the FET (145) is driven by a charging current for charging the capacitor (7).

Abstract: A method and/or apparatus used with a voltage/frequency driver for controlling a motor that maintains a motor driving magnetizing flux at low frequencies and maintains a constant desired motor speed despite relatively high slip at low frequencies. The voltage/frequency driver controls both magnetizing flux and motor speed without requiring sensing or calculating hardware in addition to hardware typically included with a voltage/frequency driver.

Abstract: A controller for driving an electric motor includes a rectifying circuit for converting AC power from a source to DC power, an inverting circuit coupled to the rectifying circuit via a DC bus for converting the DC power to controlled AC power in response to control signals and control circuitry for generating control signals for driving the inverting circuit in accordance with a preset control routine. The rectifying and inverting circuits are included in a power substrate module, while the control circuitry is included on a control circuit board separate from the power substrate module. The control circuit board is coupled to the power substrate module via a plurality of conducting pins and the controller circuitry is housed in an enclosure. A plurality of terminal conductors are supported on the control circuit board for transmitting power to and from the power substrate module via the conducting pins through the control circuit board.

Abstract: A frequency slider circuit for reducing power dissipation in the form of switching losses in a switching device when the switching device is near its desired maximum temperature limit is disclosed herein. The switching device controls an electric load, such as a motor. The frequency slider circuit samples a current of the switching device. The frequency slider circuit then uses a current transducer to convert the current to a signal level. The signal level is then processed by a model of the thermal response of the switching device. The output of the thermal model is compared to a reference signal, and if the output of the thermal model is greater than the reference signal, the switching frequency of the switching device will be lowered gradually to keep the power generated during the switching periods to be below a predetermined value. A minimum frequency clamping circuit is included to ensure that the switching frequency never drops below a minimum value, to ensure stable operation of the switching device.

Abstract: A method and/or apparatus for converting voltage using a pulse width modulator and an inverter/converter, the inverter/converter including three legs and a triangle signal generator providing a triangle signal having a peak magnitude. A plurality of sinusoidal reference signals are provided which are displaced from one another by a phase angle. The absolute values of the maximum and minimum values of the reference signals are detected, if the absolute value of the maximum signal is greater than or equal to the absolute value of the minimum signal, the maximum signal is subtracted from the peak magnitude to produce a modifier signal. If the absolute value of the maximum signal is less than the absolute value of the minimum signal, the inverted minimum signal is added to the negative of the peak magnitude of the carrier to produce the modifier signal.

Abstract: A cache memory stores data from a source. Each item of data is identified by an address having a plurality of bits divided into four groups. A multiplexer responds to a control signal by selectively applying two of the groups of bits to address inputs of a tag memory and a random access memory, and selectively applying the other two groups of bits to a data input of said tag memory. The multiplexer enables different groups of address bits to address the two memories. A comparator compares a first set of bits formed by the other two groups of address bits to a second set of bits read from said tag memory. A memory controller causes data to be read from the random access memory when the first and second sets of bits match. When the first and second sets of bits do not match, the memory controller causes data to be read from the source and stored in the random access memory. In the latter instance, the tag memory stores the bits present at its data input.

Abstract: A method for interrupting electrical power between two conductors is provided, including biasing an electrically conductive element into a conducting position between two contact regions of the conductors. The contact regions are preferably portions of arc runners coupled to the conductors. The conductors surround a magnetic core that generates an electromagnetic field due to current in the conductors. The conductive element is repelled to a non-conducting position by the electromagnetic field in response to an overcurrent condition in the conductors. A secondary response mechanism is moved in response to the overcurrent condition to maintain the conductive element in the non-conducting position. For more gradually occurring overcurrent conditions, the secondary response mechanism is attracted toward the core, displacing the conductive element to the non-conducting position.

Abstract: A motor drive particularly suited for decelerating an AC motor includes a signal converting circuit, a monitoring circuit and a control circuit. The signal converting circuit is coupled to a source of DC power via a DC bus and a capacitive circuit is coupled across the DC bus to store energy produced by the motor during deceleration of a primarily inertial load. The signal converting circuit produces and applies drive signals to the motor based on control signals from the control circuit. The control circuit produces control signals for generating an output waveform duty cycle for the drive signals suitable for maintaining a predetermined voltage-to-frequency relationship. The frequency of the output signals is selectable to control the output speed of the motor. During deceleration, the monitoring circuit detects rises in the DC bus voltage, indicating that the motor is tending to slow at a rate less than the desired deceleration rate.

Abstract: A mounting for a single in-line package (SIP) module includes an elongated slot aperture for receiving an edge of the module. The module may be a circuit board or other electrical device and preferably includes edge finger connectors. The elongated slot aperture preferably includes hemicylinders located about the periphery. The hemicylinders provide plated through conductors for connecting to the finger connectors of the module. The aperture is made according to an advantageous method in which the aperture is etched in order to remove barbs or extra copper material caused by milling the aperture. Preferably, the module fits into the aperture with an interference or size-on-size fit. The aperture may include strain relief areas.