Abstract: A inter-network interface device usable in a highly reliable industrial control system provides an interface between a producer module transmitting redundant messages in accordance with a communication protocol and a consumer module receiving the messages in accordance with a different communication protocol. The inter-network interface device includes a first network interface receiving two messages from the producer, a microprocessor capable of converting the messages from the producer communication protocol to consumer communication protocol, and a second network interface transmitting the messages to the consumer. One of the messages is reversible altered with respect to the other message. The altered message is uninverted in the consumer module, and compared to the other message to ensure that no transmission errors have occurred.

Abstract: Error detection codes implemented in standard network interface circuits are enlisted in obtaining high reliability necessary for safety systems by virtual testing of the network interface circuits using background levels of network errors. The frequency of the testing matches the frequency of the network errors.

Abstract: A high reliability network provides for measurements of network delays through pairs of transmissions of local clock values used in a first message to deduce clock value offsets and in a second message to reveal network delays.

Abstract: A system for electronically controlling physical operation of dangerous equipment is provided. The system reads data from an electronic key and controls the flow of electricity, air, water and/or hydraulic fluid, for example, to a piece of dangerous equipment. The system includes electronic keys that store electronic key data and an electronic key reader that reads the electronic key data. The electronic key data analyzer analyzes the electronic key data and produces disconnect control data based on the electronic key data and other information like the status of the dangerous equipment. The system further includes a disconnector that can disable the piece of dangerous equipment based on the disconnect control data. The disconnector can also re-enable the piece of dangerous equipment. When operated in a networked environment, the system can perform actions like logging data, scheduling personnel and material, and performing EDI for pieces of dangerous equipment and related equipment.

Abstract: A inter-network interface device usable in a highly reliable industrial control system provides an interface between a producer module transmitting redundant messages in accordance with a communication protocol and a consumer module receiving the messages in accordance with a different communication protocol. The inter-network interface device includes a first network interface receiving two messages from the producer, a microprocessor capable of converting the messages from the producer communication protocol to consumer communication protocol, and a second network interface transmitting the messages to the consumer. One of the messages is reversible altered with respect to the other message. The altered message is uninverted in the consumer module, and compared to the other message to ensure that no transmission errors have occurred.

Abstract: A bridge usable in a highly reliable industrial control system provides an interface between a producer module transmitting redundant messages in accordance with a communication protocol and a consumer module receiving the messages in accordance with a different communication protocol. The bridge includes a first network interface receiving two messages from the producer, a microprocessor capable of converting the messages from the producer communication protocol to consumer communication protocol, and a second network interface transmitting the messages to the consumer. One of the messages is reversible altered with respect to the other message. The altered message is uninverted in the consumer module, and compared to the other message to ensure that no transmission errors have occurred.

Abstract: A highly reliable industrial control system is produced using a network running a standard serial protocol on two redundant messages. A safety protocol is embedded within the standard serial protocol by adding to special error detecting data redundant with the protocol of the standard serial network. In addition, only a single network protocol module (CAN) is necessary to transfer two logical messages of data between modules. In order to still provide redundancy, the data on one of the messages is encoded in a predetermined manner, such as by inverting each bit of data, prior to transmission over the network. The data is then decoded at the destination module and compared to the data on the other logical message to determine whether a transmission error has occurred. Safety protocol may be implemented in an additional level for integrated circuits or through firmware changes in programmable aspects of the industrial controller components.

Abstract: Safety level error detection comparable to that provided by redundant wired safety relays is obtained on a backplane of a programmable logic controller or the like by a combination of error detection methods that in sum provide the requisite level of error detection required without necessitating a particular hardware requirement or duplicative message transmissions.

Abstract: A highly reliable industrial control system is produced using a network running a standard serial protocol. A safety protocol is embedded within the standard serial protocol by adding to special error detecting data redundant with the protocol of the standard serial network. In addition an overarching protocol involving timing of messages is imposed to provide the necessary level of reliability in the standard serial network. This approach allows the safety protocol to be used with a wide variety of commercially available serial communication standards without modification of the media or the specialized integrated circuits used for that communication. Safety protocol may be implemented in an additional level for integrated circuits or through firmware changes in programmable aspects of the industrial controller components.

Abstract: A high reliability network provides for measurements of network delays through pairs of transmissions of local clock values used in a first message to deduce clock value offsets and in a second message to reveal network delays.

Abstract: A highly reliable industrial control system provides for the processing of redundant control signals on as little as a single serial network without overloading the network by preprocessing input signals for coincidence and sending only the coincidence signal either periodically or on a change of state. Further compression of sent data is realized by extracting a reduced subset of transmission states from the input signals and transmitting only the transmission states.

Abstract: A highly reliable industrial control system is produced such as may use a standard network for configuration by symmetrically transmitting configuration data to intercommunicating controller components. The configuration data provides a unique identification to each component to reduce the possibility of misdirected messages and provides the protocols to be used by the components reducing the chance of garbled messages. The two components trade configuration data prior to communicating to ensure that they have the correct party.

Abstract: Safety level error detection comparable to that provided by redundant wired safety relays is obtained on a backplane of a programmable logic controller or the like by a combination of error detection methods that in sum provide the requisite level of error detection required without necessitating a particular hardware requirement or duplicative message transmissions.

Abstract: A highly reliable industrial control system is produced by opening multiple connections on a connected messaging network running a standard serial protocol. The two connections are used to transmit redundant data and include a reply message to the message producer. Errors in the messages or media failure may be detected using standard error detection codes, retry counters and deadman timers. Comparison of the data of the two messages can reveal other types of failure not apparent by these former techniques.

Abstract: Error detection codes implemented in standard network interface circuits are enlisted in obtaining high reliability necessary for safety systems by virtual testing of the network interface circuits using background levels of network errors. The frequency of the testing matches the frequency of the network errors.

Abstract: A highly reliable industrial control system is produced using a network running a standard serial protocol on two redundant messages. A safety protocol is embedded within the standard serial protocol by adding to special error detecting data redundant with the protocol of the standard serial network. In addition, only a single network protocol module (CAN) is necessary to transfer two logical messages of data between modules. In order to still provide redundancy, the data on one of the messages is encoded in a predetermined manner, such as by inverting each bit of data, prior to transmission over the network. The data is then decoded at the destination module and compared to the data on the other logical message to determine whether a transmission error has occurred. Safety protocol may be implemented in an additional level for integrated circuits or through firmware changes in programmable aspects of the industrial controller components.

Abstract: A bridge usable in a highly reliable industrial control system provides an interface between a producer module transmitting redundant messages in accordance with a communication protocol and a consumer module receiving the messages in accordance with a different communication protocol. The bridge includes a first network interface receiving two messages from the producer, a microprocessor capable of converting the messages from the producer communication protocol to consumer communication protocol, and a second network interface transmitting the messages to the consumer. One of the messages is reversible altered with respect to the other message. The altered message is uninverted in the consumer module, and compared to the other message to ensure that no transmission errors have occurred.

Abstract: A rolling mill system uses a number of autonomous control units, each associated with one piece of equipment of the rolling mill system. The autonomious control units include data indicating not only their constraints of operation, but also reflecting the constraints of operation of machines to which they are attached and with which they share common operating parameters. An autonomous control unit associated with a machine having operating parameters in common with another machine of the rolling mill system adopts the intersection of the ranges of the machine constraints of the two machines. Machine constraints are preserved to the extent possible as ranges, so as to permit flexibility in selecting and seeking goals by the individual autonomous control units.

Abstract: A rolling mill system associates an autonomous control unit with each piece of equipment in the rolling mill system. The autonomous control unit has a model of the particular piece of equipment, for example, of the rolling mill, a reheat furnace or a cooling bath, and data indicating constraints on the operation of the equipment. A metal shape to be produced is described as a set of machine independent steps, and the performance of these steps is bid upon by the autonomous control units according to the constraint models and internal goals. Bids having conflicting requirements may generate counterbids until a complete plan for the production of the product is generated.