Abstract: The present invention provides an efficient method of transferring multi-word data across a fixed width parallel bus normally transmitting a single word at a time by allocating part of the bus word to the transmission of a fractional address dividing the given addressing space into subaddresses or "fractional addresses". A data transfer request provides the desired fractional address and the data transfer response returns the fractional address value and the portion of the multi-word data corresponding to that fractional address.

Abstract: Subprograms together making up an industrial controller program are encapsulated in shells which make explicit the connection relationships and data flow directions of the subprogram normally implicit in the sharing of variables. The shells also identify the consumer/producer relationship of the variables as may be used to identify data contention problems. Actual connections between subprograms along which variables may be shared are externalized in a connection database that permits ready cross-referencing of such data sharing. Connection information stored in the shell may be used when a shell is cut and pasted to provide an initial suggestion of how to connect the new pasted shell. The automatic reconnection of the pasted shell refers to the previous connections and makes use of a hierarchical arrangement previously determined by the programmer reflecting the logic of the program.

Abstract: An industrial controller Input/Output module includes on-board processing circuitry in the form of a microprocessor and associated memory, a first programmable logic circuit and a second programmable logic circuit connected through an isolation interface. The isolation interface is comprised of optical coupling circuits. The programmable logic circuits are programmed to provide circuitry for parallel-to-serial data conversion of 24 bits of system Input/Output data on each side of the isolation interface. The data is then transferred as serial data in both directions at once in response to a shift clock signal. The data signals and the shift clock signal utilize three one-bit optical coupling devices in the isolation interface. After transfer across the isolation interface, the system Input/Output data is converted to parallel data for further processing.

Abstract: A highly distributed industrial control system employs a number of separate control modules communicating together on a shared communications medium. Each module emulates one or more basic electrical parts having electrical terminals, such as switches and relays, and transmits production messages indicating the state of the parts, such as conducting current or not. A connection list for each part in each control module defines message identifiers of other parts whose production messages are received by the control module and interpreted as current flow to one or more of its parts. The control system is programmed by generating a schematic on a programming terminal showing connections of terminals on symbols of the parts such as would represent actual wiring of the emulated parts. A parts layout diagram is used in conjunction with the schematic to identify each part to a physical module.

Abstract: A harmonic analyzer using a short sampling window eliminates truncation artifacts in the sampling of an AC power waveform by equating the length of the sample period to a period of the sampled waveform. The period of the AC power waveform is estimated from the waveform and used to produce a set of "resampled" points evenly spaced within that period as estimated from the sampled. By performing a spectrum analysis on the resampled points, artifacts at the harmonic intervals are reduced to zero.

Abstract: A method for providing a standard coordinated time throughout spatially separated functional modules of an industrial controller employs a module operating as a time-master which transmits a coordinated time value to various dependent modules through communication modules. The particular time-master is determined by an arbitration process among potential masters which examines a time quality value, indicating the precision of the time-master's clock, and incorporated in the transmitted synchronization signal. Upon the loss of a master or the introduction of a new master, mastership is reallocated so that the master time value is provided from that module having the best time quality. Offset caused by "ripple through" of the time value through communication modules is minimized by summing to that time value as it traverses a communication module with a time quantity measuring the processing time of the communication module.

Abstract: A wiring base for a bar code scanner or the like provides a conductive housing open at one face for connecting cables at various screw terminals to a circuit board providing signal processing for the signals and permitting various different-connections of the cables. The shields of the cables pass into the conductive housing to be terminated on conductive housing thereby enlisting the conductive housing as a shield around all the cables. Attachment of the scanning head to the upper face of the wiring base closes the housing to be free from the egress of dust or liquid and completes a Faraday cage around the connections while connecting two multi-pin connectors one within the base and one within the scanner, communicating the signals to the scanner. A visual indicator attached within the conductive housing indicates the presence of power and its polarity prior to connection of the scanning head to the conductive housing.

Abstract: A programmable controller for executing general instructions and relay ladder instructions employs a general purpose microprocessor together with a high speed relay ladder processor. The relay ladder instruction in a user program are executed by the special processor exclusively. When a general instruction is encountered, the special processor releases the general purpose microprocessor from a wait state and provides it with data in response to a previous long read instruction. This data is interpreted by the microprocessor to indicate the next instruction to be executed and points to a series of machine instructions terminating in another long read instruction to a designated address. When a read of this designated address is detected by the special processor, thus indicating the conclusion of the execution of the general instruction, the special processor puts the microprocessor back in the wait state and continues to execute relay ladder instructions in the user program if any.

Abstract: An industrial controller I/O module includes on-board programming circuitry in the form of a microprocessor and associated memory, a first programmable logic circuit and a second programmable logic circuit connected through an isolation interface. The programmable logic circuits are programmed by the microprocessor on power up by reading configuration data from the PROM and writing it to the logic circuits to define their I/O circuit functions in controlling the I/O drives on a controlled machine or process.

Abstract: Multiple motion controllers for controlling servo motors are connected by a digital communications link so that controlled axes of the motion controllers may be slaved together regardless of their physical proximity. A given controller broadcasts position or command signals on the communications link in response to a request report message from any another controller. A second request report message may stop the broadcasting to conserve link capacity. Time shifting implicit in the link messages is corrected by estimating the velocity of the master axis and extrapolating the position to the local axes' time of updating.

Abstract: A motor controller receives commands from multiple command sources, the commands having different types, and dynamically allocates an ownership of each command type to a particular command source based on the commands received. In one embodiment, the allocation is according to the first command source to request the command type when there is no other ownership of the command type. A masking table provides the ability to lock out any particular command type from a command source regardless of the ownership. Each command source receives a unique address from a connector system connecting it to the motor controller and, when first connected, responds to a polling by the motor controller with its address and control source type permitting multiple control sources to be automatically configured and accommodated by the motor controller.

Abstract: A highly distributed industrial control system employs a number of separate control modules communicating together on a shared communications medium. Each module emulates one or more basic electrical parts having electrical terminals, such as switches and relays, and transmits production messages indicating the state of the parts, such as conducting current or not. A connection list for each part in each control module defines message identifiers of other parts whose production messages are received by the control module and interpreted as current flow to one or more of its parts. The control system is programmed by generating a schematic on a programming terminal showing connections of terminals on symbols of the parts such as would represent actual wiring of the emulated parts. This schematic is analyzed to determine the immediate upstream neighbors of each part and the message identifiers of those parts in the control modules form the connection lists.

Abstract: A rack for an industrial controller has a metallic top and bottom plate with grooves to receive circuit cards of functional modules. A heat sink on the functional modules has flanges forming parts of the edge of the circuit cards that engage the grooves of the rack to provide a direct path of conduction from the heat sinks to the rack augmenting the cooling of the heat sink normally provided by heat sink fins. The heat sink stands away from the circuit card and has cantilevered flanges returning to the circuit card surface that provide flexure ensuring good contact between the heat sink and the grooves on the rack.

Abstract: A method of fine tuning the "gain" of a fuzzy logic controller, the controller having input and output membership functions where the input membership functions receive one or more inputs and are grouped in sets according to each input, where the gain is tuned by uniformly scaling the domains of one or more of the sets of the input membership functions.

Abstract: A transformer-coupled, bridged-T network for connection of a load to an electrical communication network includes a transformer with a center tap and two end taps, a drop cable for electrical connection of the load to the center tap and passive elements connected across the transformer to compensate for impedance of the drop cable and the load when the load is connected through the drop cable to the center tap

Abstract: Multiple motion controllers for controlling servo motors are connected by a digital communications link so that controlled axes of the motion controllers may be slaved together regardless of their physical proximity. A given controller broadcasts position or command signals on the communications link in response to a request report message from any another controller. A second request report message may stop the broadcasting to conserve link capacity. Time shifting implicit in the link messages is corrected by estimating the velocity of the master axis and extrapolating the position to the local axes' time of updating.

Abstract: A programming aid for troubleshooting real-time motion control programs controlling servo motors employs a graphical control language in which functionally related groups of instructions are represented by icons displayed on a programming terminal and interconnected by sequence lines to indicate the order of the instruction's execution. The programming terminal receives the address of the instructions being executed and identifies this address to a displayed icon to modify the icon thus indicating the internal operation of the program on a real time basis with little interruption of the control process.

Abstract: A real time three-phase analyzer stores digitized values of the signals of the three-phase circuits in memory so that they may be addressed according to circuit and sample number. Positive, negative and zero phase sequences are developed without the need for trigonometric calculation by combining samples offset in memory by a number of samples approximating 120.degree.. That number of samples may be determined for an arbitrary frequency of the three-phase system by identifying zero-crossing points of one such signal and assuming the number of samples equates to 360.degree. of phase of that circuit. The phase sequence of the three circuits necessary for the calculation of the positive, negative and zero phase sequences may be determined by comparing the relative position of positive going zero-crossings for each of the three circuits.

Abstract: A mechanism for an overload relay or the like employs a contact bar that is held in a reset position by magnetic attraction and in a tripped position by the biasing of a spring. The magnetic attraction effective in the reset condition may be overcome by a countervailing magnetic field developed by a coil driven in turn by overload sensing circuitry, or by the mechanical displacement of the contact bar away from the reset position by any small amount. Resetting is accomplished by another magnetic linkage which also may be subject to the countervailing field of the coil to prevent resetting during an overload condition.

Abstract: A navigation device for wheeled vehicles using an optical locating system to determine the vehicle's position with respect to a set of coded, and therefore separately identifiable, fixed beacons. This optically obtained navigational information is used in conjunction with information from revolution counters on the vehicle's wheels to permit operation when one or no beacons are visible, and to refine the accuracy of the position determination as derived from the optical system alone.