A servo control device to execute an operation in a discrete time system may include a velocity feedback path having a difference means calculating a pseudo-velocity from a detected position and a lowpass filter, and a PI control means executing a proportional integration control operation on a deviation between the pseudo-velocity and the position deviation to create a drive command for the driver. The velocity feedback path includes a first gain means applying a first gain to the pseudo-velocity, a delay means delaying the pseudo-velocity, and a second gain means applying a second gain to the delayed pseudo-velocity. A sum of an output of the first gain means and the second gain means is inputted to the lowpass filter, and “F.sub.a(z)=1/(1−z.sup.−1F.sub.b(z))” is satisfied where a transfer function of the PI control means is F.sub.a(z), and a transfer function of the lowpass filter is F.sub.b(z).

The present invention provides a technology for invoking a non-periodic-execution function module from a periodic-execution control program. A control system that comprises first and second control parts (C1, C2) and a storage device that stores control programs (210, 211) for a controller. The control programs (210, 211) include a periodic-execution function module (55B) that invokes a non-periodic-execution function module (55A). The first control part (C1) reflects the value of an input variable for the periodic-execution function module (55B) in an argument for the non-periodic-execution function module (55A) and outputs an execution start command for the function modules to the second control part (C2). The second control part (C2) outputs a return value for the non-periodic-execution function module (55A) to the first control part (C1). The first control part (C1) reflects the return value in an output variable for the periodic-execution function module (55B).

A method for controlling an automation system having control redundancy is provided. The automation system has at least a first controller, a second controller and a plurality of field devices connected to the first and second controller via a data bus, with the first and second controller configured to cyclically control an automation process of the automation system. The method comprises cyclically controlling the automation process via the first controller, determining a malfunction of the first controller during an (n+x)-th control cycle, where the (n+x)-th control cycle is carried out x control cycles later in time than the n-th control cycle, and sending out an n-th set of output data via a second input-output unit of the second controller to the plurality of field devices in the (n+x)-th control cycle, for controlling the automation process. An automation system is configured to carry out the method.

A control system for factory automation includes a first unit and a second unit that exchange data with each other, and a synchronization module that synchronizes a control counter included in the first unit and a control counter included in the second unit using a clock. Each of the units includes an information storage that stores information on conversion for calculating a time from a counter value of the counter of the unit, the information being shared between the units.

An EtherCAT device is disclosed. The EtherCAT device comprises a data input port to receive a signal representing data, the signal representing one of a plurality of possible logical values; and a degradation calculation circuit. The degradation calculation circuit is to read, demodulate, and convert the received signal into a digital domain representation; process the digital domain representation into slices, where the value of the received signal at a respective time is represented in a respective one of the slices; determine differences between the respective slices and reference slices; identify an intended logical value of the received signal responsive to the determined differences; determine a quantification of error at the respective time responsive to the identified logical value and the determined differences; and determine a signal quality index responsive to the determined quantification of error.

A communication system for an industrial process includes multiple slave modules connected in series with a master controller. The master controller stores a communication schedule that defines an ordered sequence of messages and identifiers associated with each message. The master controller transmits messages downstream through the slave modules to a terminal one of the slave modules. The terminal slave module generates a return message that is transmitted upstream to the master controller. Each slave module receives each downstream message, identifies based on the message identifier whether the message is associated with response information from the slave module, and inserts the response information into corresponding upstream messages.

A software defined distributed control system (SDCS) in a process plant includes an application layer that includes a plurality of containers instantiated in a data cluster. Each of the containers is an isolated execution environment executing within the local operating system of a respective computing node. The containers cooperate to facilitate execution of a control strategy in the SDCS, and includes a hyper converged infrastructure (HCI) operating across the data cluster, which HCI is configured to communicate with the application layer via an adapter service. The HCI includes software-defined (SD) compute resources, SD storage resources, SD networking resources, and an orchestrator service. The orchestrator service is programmed to configure a first container to include a service executing within the first container. It also assigns the first container to execute on an available hardware resource to control a plurality of field devices operating in the process plant.

A software defined distributed control system (SDCS) in a process plant includes an application layer that includes a plurality of containers instantiated in a data cluster. Each of the containers is an isolated execution environment executing within the local operating system of a respective computing node. The containers cooperate to facilitate execution of a control strategy in the SDCS, and includes a hyper converged infrastructure (HCI) operating across the data cluster, which HCI is configured to communicate with the application layer via an adapter service. The HCI includes software-defined (SD) compute resources, SD storage resources, SD networking resources, and an orchestrator service. The orchestrator service is programmed to configure a first container to include a service executing within the first container. It also assigns the first container to execute on an available hardware resource to control a plurality of field devices operating in the process plant.

A process control system includes a plurality of field devices operating to control a process. A communication infrastructure couples the field devices to a software-defined control system (SDCS) that receives data from the field devices and transmits instructions to the field devices. A data cluster, executing the SDCS, includes a plurality of computing nodes, each of which includes a processor executing an operating system, a memory, and a communication resource coupled to one or more other computing nodes in the data cluster. First and second containers, each of which is an isolated execution environment, are instantiated on a first computing node within the operating system of the first computing node. The second container is instantiated within the first container. The first and second containers correspond to levels of a hierarchical structure of the SDCS.

An I/O server service interfaces with multiple containerized controller services each implementing the same control routine to control the same portion of the same plant. The I/O server service may provide the same controller inputs to each of the containerized controller services (e.g., representing measurements obtained by field devices and transmitted by the field devices to the I/O server service). Each containerized controller service executes the same control routine to generate a set of controller outputs. The I/O server service receives each set of controller outputs and forwards an “active” set to the appropriate field devices. The I/O server service may utilize a quality-of-service metric to determine which controller outputs and/or I/O channel is “active.” The I/O server service and other services, such as an orchestrator service, may continuously evaluate performance and resource utilization in the control system, and may dynamically activate and deactivate controller services as appropriate.