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.
This application is a continuation of Ser. No. 09/591,604, filed Jun. 9, 2000 now U.S. Pat. No. 6,788,980 entitled METHODS AND APPARATUS FOR CONTROL USING CONTROL DEVICES THAT PROVIDE A VIRTUAL MACHINE ENVIRONMENT AND THAT COMMUNICATE VIA AN IP NETWORK (the teachings of which are incorporated herein by reference), which claims the priority of the following United States Patent Applications: U.S. patent application Ser. No. 60/139,071, entitled OMNIBUS AND WEB CONTROL, filed Jun. 11, 1999; U.S. patent application Ser. No. 60/144,693, entitled OMNIBUS AND WEB CONTROL, filed Jul. 20, 1999; U.S. patent application Ser. No. 60/149,276, entitled METHODS AND APPARATUS FOR PROCESS CONTROL ("AUTOARCHITECTURE"), filed Aug. 17, 1999; U.S. patent application Ser. No. 09/345,215, entitled PROCESS CONTROL SYSTEM AND METHOD WITH IMPROVED DISTRIBUTION, INSTALLATION, AND VALIDATION OF COMPONENTS, filed Jun. 30, 1999.
A virtual machine operating system for communication between first and second applications which execute in different user portions of the virtual machine operating system and use Internet Protocol (IP). The virtual machine operating system comprises a first user portion, a second user portion and a base portion. The first user portion executes the first application and includes a first device driver for a first virtual network interface card (NIC). The second user portion executes the second application and includes a second device driver for a second virtual NIC. The base portion is shared by the first and second user portions and includes the first and second virtual NICs. The base portion maintains a table of IP addresses by which each device driver addresses its respective NIC and other, corresponding addresses by which the base portion addresses the virtual NIC. The first device driver is programmed to receive an IP datagram from the first application and pass it to the first NIC using IP. The datagram includes an IP address of the second virtual NIC and an indication that the second application should receive the datagram. The base portion is programmed to determine the other address of the second NIC based on the table and transfer the datagram to a storage location associated with the second virtual NIC or the second device driver.
A network optimization system that uses multiple devices having different combinations of hardware and software (i.e., platforms). The system assesses, controls and optimizes network performance , providing an efficient interface for installing, configuring and operating various features of the optimization system. Intelligence objects operate at the server node level to dynamically analyze system processes at each server node. One feature allows an object to generate a number representing a local utilization, a measure of one or more performance factors in the platform hosting the object. The local utilization value can be passed to another platform system hosting a second intelligence object, generating its own local utilization value or combining its local utilization value with the passed value to create a composite utilization value that reflects performance of both platforms. Where different values are from different platforms, the system resolves, adjusts, or normalizes the values to achieve a composite value.
A meter reading system of the present invention enables transmission of data between utility meter endpoints and readers. In a first embodiment, the endpoint provides a short message providing its identification to the reader and immediately enters a listen mode. If the reader hears the short message, it can immediately respond and request additional information from the endpoint. If the reader does not hear the short message or does not request additional information during the endpoints listening period, the endpoint enters a sleep mode until its next transmission time. In another embodiment, the endpoint transmits an SCM via AM communication to the reader. The reader can then request additional information and the endpoint can respond with the information via two-way FM communication. In another embodiment, the endpoint is capable of transmitting interval data to the reader via either AM or FM communication.
A client quarantine agent requests bill of health from a quarantine server, and receives a manifest of checks that the client computer must perform. The quarantine agent then sends a status report on the checks back to the quarantine server. If the client computer is in a valid security state, the bill of health is issued to the client. If the client computer is in an invalid state, the client is directed to install the appropriate software/patches to achieve a valid state. When a client requests the use of network resources from a network administrator, the network administrator requests the client's bill of health. If the bill of health is valid, the client is admitted to the network. If the bill of health is invalid, the client is placed in quarantine.
