An improved matching system for trading instruments in which the occurrence of automatically confirmed trades is dependent on receipt of match acknowledgement messages by the host computer (200) from all counterparties (KS A, KS B) to the matching trade. The host computer (200) matches like bids and offers provided thereto by the various keystations (KS A, KS B) in accordance with a predetermined matching criteria. Each of the keystations (KS A, KS B) includes a trade status timer (300, 302) and a display (310, 312) for timing receipt of a confirmed trade and/or ticket generation message from the host (200) after the keystation (KS A, KS B) has sent a match acknowledgement message and for displaying an "unconfirmed trade" status message awaiting receipt of the "confirmed trade" indication from the host (200). An alarm and a display message is provided at the keystation (KS A, KS B) when the "confirmed trade" indication is not timely received. The host (200) receives match acknowledgement messages from all of the counterparties (KS A, KS B) to the match before confirming a trade. A ticket is not generated at the keystation (KS A, KS B) until the trade has been confirmed by the host (200).

Offer matching system having timed match acknowledgment

Apparatus and methods for controlling a system that operates responsive to a plurality of input control signals are disclosed. During operation the system generates a plurality of output status/control signals. A master controller has at least first and second controllers. The first controller outputs and inputs signals over a first communication path, and the second controller outputs and inputs signals over a second communication path. The first and second controllers output signals based on input signals received over the first and second communication paths, respectively, and also based on stored control data. A plurality of input/output modules are provided. Each of the input/output modules has first and second slave controllers. The first slave controller of each of the input/output modules inputs and outputs signals over the first communication path to the first controller, and the second slave controller outputs and inputs signals over the second communication path. Each of the first slave controllers outputs and inputs signals to and from a first input/output circuit, and each of the second slave controllers outputs and inputs signals to and from a second input/output circuit. Each of the input/output modules also includes a combiner circuit. At least some of the input control signals for controlling the system are generated by the combiner circuit of each input/output module based on signals output from both the first and second input/output circuits. The output control signals for controlling the system are generated based on output status/control signals from the system that are coupled to each of the first and second input/output circuits of the input/output modules.

Distributed input/output control systems and methods

A system and method for controlling operation of a plurality of elements in an automated process, such as a production process, and indicating error conditions as they occur. Each unique set of input and output conditions of the various system elements defines a unique logic state or zone. Thus, there are defined a multiplicity of valid system logic states or zones, each having a unique input/output image. A predetermined sequence of zones, productive zones representing designed machine operations, is stored in a zone table. All zones not explicitly defined in the zone table are automatically treated as error zones. A zone engine automatically cycles to observe any change in input/output image. Any change in inputs from the various system elements automatically transfer action to the unique zone associated with such inputs, resulting in corresponding changes in control outputs to the system elements and/or display an error message as appropriate.

Distributed logic control system and method

A sprinkler system including a controller having a manual data entry device, a processor and a sprinkler controller. Data is entered through the data entry means relating to conditions in each of a number of zones in which sprinkling is to occur with respect to the amount of water needed to be applied to that zone and the soil water infiltration rate. Upon receiving this information, the processor determines for each zone the number of cycles and the length of time in each cycle that water is to be applied not only so that the amount of water applied during each cycle does not exceed the amount of water the soil can absorb during that cycle, but also so that the total amount of water needed by that zone is applied. The processor employs the number of cycles and the length of on time per cycle to organize the cycles for all of the zones, creating an application program. The application program is employed by the sprinkler controller to generate control signals for executing the application program on an automatic basis. An operator provides data concerning which days an application is desired, the type of soil in the area to be irrigated, the type of sprinkler for each zone, the water need of the vegetation in each zone and the desired start time. Then, the controller calculates the number of cycles for each zone per application and the length of time in each cycle the sprinkler is to be on.

Sprinkler controller which computes sprinkler cycles based on inputted data

An emergency shutdown test, wherein the emergency shutdown test system includes an emergency shutdown device controller and sensors to provide data to the controller. The emergency shutdown device controller has a processor, a memory coupled to the processor and an auxiliary input couple to the processor, wherein an emergency shutdown test is stored in the memory, and the auxiliary input is adapted to receive a binary signal and sensor data. A first routine is stored in the memory and is adapted to be executed on the processor to cause the emergency shutdown test to be performed in response to the receipt of the binary signal at the auxiliary input. The memory is also adapted to store a second routine, wherein the second routine is adapted to be executed on the processor to cause sensor data to be recorded in the memory during the emergency shutdown test. The processor compares a plurality of predetermined limits to the received sensor data to determine if the valve is fully operational or if possible problems exist.

System to manually initiate an emergency shutdown test and collect diagnostic data in a process control environment

A programmable industrial logic controller is provided for accomplishing the sequencing operations and other related control tasks performed by a logic control system of the type adapted for controlling machine and process equipment. The controller includes input means, memory means, control logic means, automatic self-test means, output means and manual test means. The input means functions to receive inputs supplied to the controller corresponding to the existing conditions of a plurality of parameters of the equipment being controlled. A pre-established set of instructions is stored in the memory means relating to the operation of the equipment being controlled. The control logic means functions to operate in response to a set of instructions stored in the memory means. Further, the control logic means functions to generate outputs, for controlling the operation of the equipment, from the series of instructions extracted from the memory means. Automatic self-test means are provided for periodically performing a self test of the controller to determine whether the controller is functioning properly. The output means is connected in circuit relation with control logic means and receives therefrom the outputs generated thereby. The outputs received by the output means are supplied thereby to the equipment being controlled. The manual test means are provided to permit manual test of selected controller functions.

J Prentice

Papers

Automatic self-testing programmable industrial controller