Abstract: Arbitration between collisions is performed by means of a special arbitration path ARB conveying access requests expressed in the form of arbitration frames ARB %. An arbitration frame includes a priority field defining different classes of traffic, and a numerical field identifying each station, together with bits that relax priority constraints. The application of arbitration frames is subordinate to recognizing that a delimiter channel of the data path DATA is in an active state. The invention is applicable to industrial networks or buses.

Abstract: The process disclosed is appliable to transmission of data of the multiplexed series type between entities capable of emitting or receiving data, to or from the line. Each entity connected to the line can access all the data flowing in the line, and all the exchanged data are modeled by a distributed data base which is updated and maintianed by the fact that each entity stores and updates a local copy of the corresponding useful part of the data base it contains. Each time an entity is placed in service, a coherence check is carried out to ensure that the emitting and consuming entities interpret data in the same way. The coherence check is carried out by a protocol without prior contact or acknowledgement.

Abstract: A terminal for generating programs usable by a programmable controller comprising: a screen; a keyboard having more especially a set of keys assigned to graphic symbols and a processor for generating, from the data entered on the keyboard, a program usable by the controller and storage thereof. The symbols of at least one contact type graphic representation mode and a sequential type representation mode are assigned to said graphic keys.