Abstract: A pilot light on a relay or other industrial control module provides human readable information with low frequency modulation and machine readable information at high frequency modulation unintelligible to the human eye. The use of the pilot light eliminates the need for a separate and space consuming human readable display and the modulation method may be a bar code modulation to be readable by commercially available bar code readers.

Abstract: A module interfaces a programmable controller to several serial communication networks for the exchange of data carrying messages. A central processor controls the transfer of data between the module and other programmable controller components. The module has a separate port circuit for each of the networks permitting communication using different protocols. Messages received through one port circuit can be routed to another port circuit or other programmable controller components as specified by routing data stored in the module. The module also can be configured to detect when a given sequence of data is contained in a received message or to parse a section of data from the message. In these cases, an indication of whether the data sequence was found or the parsed data is routed to a designated output of the module.

Abstract: The present invention is an electric switch for switching individual phases of multi-phase AC electric power. The switch has at least one pair of fixed terminals with each terminal of the pair having an ear extending upward in a vertical plane. The switch also has a conducting device with contacts that extend downward in the vertical plane corresponding to the fixed terminals. Moving contacts are mounted to an axially translatable contact carrier and engage contemporaneously in the vertical plane with the contacts from the conducting device and the fixed terminals when the contact carrier slides into an "on" position. Electrical power is then able to flow from the line-side fixed terminal, through the conducting device, to the load-side terminal. The contact carrier is translated axially by the drive mechanism. The drive mechanism employs over-center shifting and lost-motion switching technology to prevent the switch from being in a partially "on" position.

Abstract: A method for a distributed processing system which includes the steps of developing a control program for controlling outputs at a plurality of I/O nodes, distributing executable portions of the program to the I/O nodes through a network, broadcasting input status data from the I/O nodes on the network and controlling the outputs at the I/O nodes in response to the input status data broadcast on the network and the executable portions of the program residing at the I/O nodes.

Abstract: A machine is operated by a programmable controller that executes a ladder logic control program. A custom ladder logic processor is provided for high speed execution of the more common ladder logic instructions and a microprocessor interprets the remaining ladder logic instructions. A first section of memory contains a ladder logic control program in which some of the instructions are macro instructions executable by the ladder logic processor. Each macro instruction specifies an operation code, a first memory file containing data to be processed by the macro instruction, a second memory file containing control data governing the processing, and a storage location for results produced by execution of the macro instruction. Another memory section stores a library file containing a ladder logic software routine for each macro instruction, and stores a directory which identifies a starting location of the macro instruction routine for each operation code.

Abstract: Data is sent over a digital communication network in a message frame which includes a header, a data field and an end delimiter. An analyzer for such a network evaluates the response of network interface devices to test message frames. Included in the analyzer is a mechanism for creating a test message frame which allows the user to define a number of pad-idle symbols, a sequence of symbols for a start delimiter, a series of symbols for the data field and a set of symbols for the end delimiter. The use defined test message frame may include invalid symbols to test the error response of the interface device. A transmitter is provided for repeatedly sending the test message frame to the network interface device with a given number of silence symbols inserted between each repetition. The analyzer has a section for receiving message frames back from the network interface device and sequentially comparing the symbols of the test message frame to those of the received message frame.

Abstract: A programmable controller governs the operation of a piece of equipment by executing machine language instructions compiled from a ladder diagram type control program. The control program as stored in the controller includes not only compiled machine language instructions, but also a tokenized version of the source code from which certain machine language instructions were compiled. The source code is provided only for those portions of the machine language program which cannot be easily decompiled to produce the corresponding source code. This program storage facilitates subsequent editing of the stored program via a terminal connected to the programmable controller. During the editing process, the original ladder diagram can be reconstructed from a combination of the machine language instructions and the tokenized version of the source code. In doing so, the machine language instructions, which have a one-to-one correspondence with the source code instructions, are decompiled using conventional techniques.

Abstract: Fuzzy logic programming is provided for machine and process controllers. New input and output instructions are devised for ladder diagram programming, as well as methods of downloading fuzzy logic instructions from a programming terminal to a programmable controller processor and methods for executing such instructions in the programmable controller processor.

Abstract: An apparatus for tightening threaded fasteners to any desired proportion of the way through a torque-angle specification window defined by low and high angle limits and low and high torque limits. The torque rate for the joint is determined from torque and angle measurements taken during tightening and compared to boundary ratios which are determined as the rates of change of torque with respect to angle from a threshold torque to the corners of the specification window. A final target parameter value of either torque or angle is calculated based upon this comparison which is approximately halfway through the specification window along a projection of a torque-angle characteristic curve for the fastener which is determined from the torque rate. Correction factors are also provided for tool overrun depending upon whether torque or angle control is used and a reject rate margin is employed to account for nonlinearities which otherwise may lead to unacceptable assemblies.

Abstract: A communications interface circuit couples a host processor to a pair of serial communications links. A shared memory is employed to pass message data and network management data between the host and the interface circuit, and each can interrupt the other through interrupt control lines. The shared memory stores a handshake segment that includes interrupt flags and acknowledge flags which enable a large number of different interrupt events to be efficiently serviced.

Abstract: A device protects an electric load, such as a motor, from excessive current levels. The current flows from a source to the load through a switch and a primary winding of a current sensing transformer. The voltage across a secondary winding of the current sensing transformer is rectified to produce a voltage which is measured to determine the level of current through the load. The voltage across the secondary winding also powers components of the device. In a first mode of operation, current from the secondary winding is applied to charge a power supply capacitor. In a second mode of operation the level of the rectified voltage is sensed to produce a sample of the level of the current flowing through the load. From this sample the change in temperature of the load since a previous sample is calculated and used to derive the present load temperature. When the present load temperature exceeds a defined threshold level, the switch is opened to disconnect the load from the electricity source.

Abstract: A palm operable electrical switching apparatus which is integrally constructed with the cover plate of an electrical junction box. The switching apparatus comprises a padded button assembly which is easily operable from off-center directions, an activator assembly which converts motion transferred from the button assembly to straight line movement suitable for operating an electrical switch such as a contact block and a contact block positioned for actuation by the activator assembly. The switching apparatus enables a higher degree of operational flexibility and greater amount of conformity with human operators.

Abstract: A photoelectric control unit including an electronic system having a system architecture which is adapted for allowing the unit to readily and accurately determine its own operating margin. This architecture system includes a pair of variable gain modules which operate in conjunction with a pair of separate signal channels. The signal channels have comparators for comparing signal amplitudes on their respective channels with a common reference level. Operating margin values are determined by varying the gain of the amplification modules and tracking the output from the comparators on the signal channels. The photoelectric control unit can then use operating margin values to automatically set the system gain and thereby adjust the sensitivity of the unit for optimum performance.

Abstract: A image processing apparatus receives two video signals representing different video images. Included in the processor are a number of dual ported memories, each capable of storing a field of the video images. A designation is provided as to whether the images contain a single field or two interlaced fields per image and which of the memories is to store each field. The processor is designed so that both video images can be simultaneously received and stored in the memories. Once a predesignated amount of the received video images have been stored, selected portions of the image data can be read from the memories for processing before the entire image has been stored. The two video images also can be received at different times, in which case the processor halts any image processing which is occurring in order to acquire and store a later image. The processing is performed on the pixels of the image that lie within a user defined window.

Abstract: A programmable controller has a chassis which removably holds a plurality of functional modules. The chassis has a backplane with conductors and connectors that electrically connect the modules. These conductors carry module enable, read, and write control signals, as well as byte addresses and data. Another conductor carries a signal, which when true designates that files of data, as opposed to discrete bytes of data, are being exchanged over the backplane data conductors. Each module stores identification and diagnostic data as a number of individually addressable bytes. The identification and diagnostic data is obtained from a given module by sending an active module enable signal to it. At the same time the given module is sent inactive read and write signals and an active data file transfer signal. This combination of signals is used only to read the identification and diagnostic data and is not used to exchange other types of data with functional modules.

Abstract: A programmable controller includes a processor module and a number of input/output modules housed in a rack. Each input/output module contains a circuit that identifies characteristics of the module to the processor module. The circuit has a parallel input port and a parallel output port The outputs and inputs of the two ports are interconnected in a predefined manner according to the module characteristics. In addition, inputs of the input port are coupled to either a positive or negative voltage source to identify other module characteristics. By sequentially sending data to the output port and then reading data from the input port of each input/output module, the processor can identify the characteristics of the modules in the programmable controller.

Abstract: A programmable controller has a rack that electrically connects a number of I/O modules to a processor module. The processor module includes a external device communication interface section and a general purpose processor section electrically coupled together by a set of common buses. Both of these module sections include a microprocessor and memory connected by an internal set of buses which are isolatable from the set of common buses. The isolation capability permits the different sections to perform their operations simultaneously. A shared system memory and an rack interface are coupled to the common buses for the exchange of data with the I/O modules. A unique ladder logic processor also is connected directly to the common buses. The ladder logic processor includes a hardwired Boolean bit logic processor and a custom microcoded processor to execute instructions of a ladder type control program.

Abstract: A programmable controller for sensing the status of input devices and controlling the state of operating devices in accordance with a stored ladder logic control program includes a state machine instruction. A memory is provided for storing data regarding each state of an apparatus being controlled. This data defines the status of apparatus operating devices for each state, and the legitimate transitions from that state to other selected states, along with a Boolean logic expression of selected input conditions which determines when a state transition should occur. A processor responds to the state machine instruction by examining the truth of the Boolean logic expressions for the present state of the apparatus to detect if a state transition should occur. Upon such a detection controller advances to the state associated with the detected true expression. State transitions also can be defined as occurring upon a specified change in the status of a single input.

Abstract: A memory circuit for storing words of data has two memory banks each formed by a plurality of memory devices connected in parallel. In a first mode, the memory circuit responds to an initial request for access and an address signal by reading data from a storage location in one of the memory banks. Subsequent requests for access to contiguous storage locations do not require an address signal, instead a control mechanism responds by generating an address to read data alternately from storage locations in the first and second memory banks. In a second mode, the memory circuit responds to every request for access to the memory circuit by enabling access to the first or second memory bank as indicated by an address which accompanied the request. The memory devices of a given bank are erased and programmed in parallel.

Abstract: A controller for an injection molding machine controls the injection ram by means of profiles having segments with programmable setpoints and boundary points. A profile associated with a particular stage of the injection molding cycle may be assigned one of several control functions having dependent variables of velocity or pressure and independent variables of time or ram position. The particular control function may be changed between injection stages. The programmable setpoints permit accurate representation of complex profiles with a limited number of segments.