Abstract:
A simple modification to a proportional integral controller allows for non-linear control strategies while maintaining the simplicity of set up and tuning of the loop through modifying the proportional and/or integral gains K.sub.p, K.sub.j by a linear or parabolic function of the feedback error signal. Provision is made for symmetrical or asymmetrical gain modification functions.
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 programmable controller for closed-loop positioning control has a main processor unit, and an I/O interface rack in which a master I/O positioning module and three satellite I/O modules are mounted and connected to servomechanisms to control motion along three axes of a controlled machine. Move data is transmitted from the main processor unit to the master I/O positioning module in data blocks, with the number of transmissions varying, depending upon a mode of axis coupling that is used in controlling the particular machine. The master I/O positioning module converts move data from a user program format to a binary format and transfers it to the satellite I/O modules, each of which performs closed-loop positioning control of a respective axis of motion. The processor on each satellite I/O module also determines a position prior to the end of each move to apply a user-programmed deceleration when needed to blend moves having different velocities.
Abstract:
A numerical control system includes a main processor which performs such functions as interpolation and outputting of motion command signals to the servomechanisms on a machine tool. A separate programmable interface processor connects to the main processor bus structure and it operates as a programmable controller to control the discrete digital I/O devices associated with the machine tool. A third processor couples through a serial data link with the main processor and it operates to service peripheral I/O devices associated with the front control panel on the numerical control system.
Abstract:
A programmable controller includes a processor which executes a control program to alter the state of an output image table stored in a read/write memory in response to the state of an input image table stored in the memory. An input/output scanner circuit connects directly to the read/write memory and periodically steals a memory cycle from the processor to couple the status of input and output devices with corresponding bits in the input and output image tables. The rate at which the scanner circuit operates is independent of the processor speed and is selected to accommodate the input/output interface circuitry on the programmable controller.
Abstract:
A reflex I/O card for an industrial controller receives enabling inputs from the executed control program and triggering inputs from an industrial process to provide outputs at a fixed delay in time or portion of a machine cycle after the inputs through dedicated hardware thus avoiding transmission delays and processing delays associated with the communication of information to a central processor and the execution of the control program.
Abstract:
A multi-tasking operating system for real-time control of industrial processes integrates ladder type programs and state-type programs by viewing each as a series of instructions with an implicit pointer list pointing to the next instruction. A fixed number of instructions of each program task are executed after which the effective pointer to the next instruction is stored toward the next time that task is invoked. Multiple tasks that need to be coordinated can be linked with subtasks that can be guaranteed complete execution by allocating sufficient instructions to those subtasks.
Abstract:
A method and apparatus for incorporating fuzzy logic into a feedback controller is provided. An error signal and the derivative of feedback or error is provided to the fuzzy logic to develop a proportional and differential signal, the differential signal is subsequently integrated and added to the proportional signal to create a control output of the controller. The fuzzy rules of the fuzzy logic decrease the integral term under situations that might lead to "wind-up".
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 eight-bit microprocessor sequentially reads controller type instructions from a memory and applies the operation codes of selected ones of the instructions to a hardwired Boolean processor. The microprocessor also couples status words between an I/O image table stored in the memory and the I/O interface racks which connect the programmable controller to the machine being controlled. In general, those controller type instructions which are word oriented are executed by the microprocessor and those which are single-bit oriented are executed by the Boolean processor. The Boolean processor is operable in combination with the microprocessor to examine selected status bits in the I/O image table and to set selected status bits therein to a logic state which is determined in part by the state of the examined status bits.