The invention provides improved methods and apparatus for control using field and control devices that provide a virtual machine environment and that communicate via an IP network. By way of non-limiting example, such field device can be an “intelligent” transmitter or actuator that includes a low power processor, along with a random access memory, a read-only memory, FlashRAM, and a sensor interface. The processor can execute a real-time operating system, as well as a Java virtual machine (JVM). Java byte code executes in the JVM to configure the field device to perform typical process control functions, e.g., for proportional integral derivative (PID) control and signal conditioning. Control networks can include a plurality of such field and control devices interconnected by an IP network, such as an Ethernet.

Methods and apparatus for control using control devices that provide a virtual machine environment and that communicate via an ip network

A computer system in a fault-tolerant configuration employees multiple identical CPUs executing the same instruction stream, with multiple, identical memory modules in the address space of the CPUs storing duplicates of the same data. The system detects faults in the CPUs and memory modules, and places a faulty unit offline while continuing to operate using the good units. The faulty unit can be replaced and reintegrated into the system without shutdown. The multiple CPUs are loosely synchronized, as by detecting events such as memory references and stalling any CPU ahead of others until all execute the function simultaneously; interrupts can be synchronized by ensuring that all CPUs implement the interrupt at the same point in their instruction stream. Memory references via the separate CPU-to-memory busses are voted at the three separate ports of each of the memory modules. I/O functions are implemented using two identical I/O busses, each of which is separately coupled to only one of the memory modules. A number of I/O processors are coupled to both I/O busses. I/O devices are accessed through a pair of identical (redundant) I/O processors, but only one is designated to actively control a given device; in case of failure of one I/O processor, however, an I/O device can be accessed by the other one without system shutdown.

Fault-tolerant computer system with online recovery and reintegration of redundant components

Methods and apparatus for control configuration with versioning, security, composite blocks, edit selection, object swapping, formulaic values and other aspects

A system and method for maintaining logically consistent backups using minimal data transfer are presented A system comprises a backup system having a backup storage device and one or more primary systems having mass storage devices that are to be backed up on the backup storage device The primary systems identify changes that are going to be made to the mass storage device The combined effected locations in the mass storage device of these identified changes are then captured in a static snapshot when the mass storage device is in a logically consistent state Only those data blocks changed since the last backup are then transferred to backup system The backup system can then store these changes or apply the changes to the backup storage device in order to bring the backup storage device current to a particular point in time

Backup system that takes a snapshot of the locations in a mass storage device that has been identified for updating prior to updating

Connection objects or other such data structures facilitate establishing and configuring connections between objects that model components in a process control system. A first set of data structures (e.g. the object connection type structures) identify valid types for component-to-component pairings and the respective roles of each component in the pairing (e.g., parent or child, source or sink). A second set of data structures (e.g., the parameter connection type structures) supply similar information for parameter-to-parameter connections. Together, these data structures can be used, for example, to validate component-to-component connections suggested by the user and to automatically configure parameter-to-parameter connections. Actual connections, both at the component or parameter level, are reflected using parameter overrides within the parameterized object model—with which the connection objects are constructed.

Process control configuration system with connection validation and configuration

A synchronizing circuit synchronizes the asynchronous ready signals for two separate microprocessor subsystems that are running synchronously as part of a fault tolerant computer system. Duplicated synchronization circuits, confined in a master-slave arrangement, are utilized with the duplicate microprocessors. Storage and gating circuitry are used to provide the precise timing signals required for such synchronization.

Ready line synchronization circuit for use in a duplicated computer system

A synchronizing circuit that synchronizes the non-maskable interrupt (NMI) input signals of two separate microprocessor subsystems that are running synchronously as part of a fault tolerant computer system. This circuit enables both microprocessors to detect and respond to an error condition at an identical point in their relative bus timing sequence even though there may be a real time skew between the bus timing of these two subsystems. Storage and gating circuitry are used to provide the precise timing signals required for such synchronization.

Interrupt synchronizing circuit

A Unique Phase Difference Measuring Circuit which measures the phase difference between a reference pulse train and a slave pulse train. The present invention includes delay lines that determine the phase difference between the pulse trains which can be read directly by a microprocessor.

Unique phase difference measuring circuit

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Ready line synchronization circuit for use in a duplicated computer system

Interrupt synchronizing circuit

Unique phase difference measuring circuit