Abstract: A pass-through table is developed to work in conjunction with an I/O table of a centralized industrial controller to permit a centralized controller to work seamlessly with a highly distributed control system. The pass-through table indicates data used in common between the centralized controller and the distributed controller and monitors a link connecting the distributed controller for changes in variables on the pass-through table to write those changes to the I/O table of the centralized controller. Conversely, changes in the I/O table of the centralized controller are detected and transmitted out to the common link to the distributed controller.

Abstract: A method of reconstructing a control program from portions of that program contained in distributed processor modules of a distributed control system links each portion of the program with a source identifier. When the portions are collected, they are sorted by source identifier and merged to reveal the original control program as may be required for editing or the like.

Abstract: A system for interconnecting the bus structure of separate I/O block units to form a common system backplane for data communications purposes. The system includes sets of pins and matching pin receptacles electrically coupled to bus structures on circuit boards installed on base units onto which different types of I/O modules can be removably mounted. The pins and pin receptacles for each base unit are mounted on opposite lateral sides of the base units. The pins and pin receptacles are constructed and arranged for convenient interconnection between the bases of adjacent units whereby a common system backplane may be formed.