Abstract: A serial control apparatus includes a main controller (2) and a plurality of nodes (3) each serving as an auxiliary controller normally serially arranged on a loop-shaped signal transmission line (1). Each node (3) extracts data for the present node among from the data delivered from the main controller (2) as time elapses so as to allow the terminal units (A) associated with the present node to be properly controlled. In addition, the node inserts the output data from the terminal units (A) into a time slot corresponding to the present node and then delivers to the signal transmission line (1) the output data which in turn are transferred to the main controller (2) via other nodes on the downstream side. To assure that the data extracting circuit operates properly, two latching circuits, i.e., first and second latching circuits (311, 312 to 315) are serially arranged in a signal passage by way of which the extracted data are fed to a driver (316) for the corresponding terminal units.

Abstract: An apparatus for carrying out serial control and a method of controlling the apparatus wherein the apparatus and the method are employable for a centralized control system for various machinery such as press, machine tool, ship, aircraft or the like machine as well as a centralized control system for unmanned conveyor, unmanned warehouse or the like installation. The apparatus comprises a plurality of nodes connected in series one after another and a main controller connected to the nodes. A data row length of data included in a signal from the node at the preceding stage is counted by a data row length counter and the counted data row length is compared with data row length data included in the signal from the node at the preceding stage. When the counted data row length does not coincide with a data row length representative of the data row length data, this non-coincidence is determined as a data row length abnormality thereby to generate an error signal.

Abstract: If electromagnetic waves are emitted from a plurality of points on the ground surface above a material (TG) buried under the ground, an echo image (EP) formed from the data of propagation times of reflected waves at each of the points describes a hyperbola as a result of expansion of the transmitted electromagnetic waves. An operation is carried out to overlap on the echo image (EP) a false echo image (DM) which lies on the same coordinate system and which consists of a similar hyperbolic image. If the two echo images (DM, EP) are overlapped upon each other as the result, the vertex position and the expansion of the opening of the echo image (EP) can be determined from the data of the false echo image (DM). The propagation velocity of electromagnetic waves under the ground is then calculated from the data that represents the vertex position and the expansion of the opening.