초록 ▼

A process control system includes redundant digital controllers and a plurality of input/output (I/O) modules for interfacing with remote field sensors and actuators. Bi-directional communication between controllers and I/O modules is achieved by a parallel-wired, process I/O bus. Failures within th

A process control system includes redundant digital controllers and a plurality of input/output (I/O) modules for interfacing with remote field sensors and actuators. Bi-directional communication between controllers and I/O modules is achieved by a parallel-wired, process I/O bus. Failures within the system, including the bus structure itself, that continually keep the bus active (i.e., in a low state) are isolated by a combination of software diagnostic routines for performing bus checkout and a unique quick disconnect feature that readily isolates the fault condition first between the I/O module nest area and the controllers, then, if necessary, to individual I/O modules. During fault isolation procedures, individual I/O modules may be disconnected from the bus while the values of field signals are simultaneously maintained to provide minimum process upset.

대표청구항 ▼

In a control system for providing direct digital control over an industrial process of the type having a digital controller communicating with a plurality of sensors and actuators located within a process field area, said controller including in a first location a central processing unit and associa

In a control system for providing direct digital control over an industrial process of the type having a digital controller communicating with a plurality of sensors and actuators located within a process field area, said controller including in a first location a central processing unit and associated data storage means for performing operations respecting the condition of said process and in a second location an input/output connector housing area for holding a plurality of input/output modules that receive and send field signals to and from said sensors and actuators, said controller further including a communications bus linking said first and second locations such that said input/output modules are connected in parallel along said bus when inserted in said connector housing area, the improvement in said control system for detecting and isolating failures within said controller comprising: means for detecting a fault condition within said controller; means responsive to said detector means for providing an indication of said fault condition; means for isolating said fault condition between either said first location or said second location; said means for isolating including means for rapidly disconnecting said input/output modules from said first location, whereby the absence or continuance of said fault indication pinpoints whether said fault condition is in said first or second location.