BS 7404 is a series on telecontrol equipment and systems. Telecontrol equipment and systems function best when used from a short distance. BS 7404-1.4 applies to telecontrol equipment and systems with coded bit-serial data transmission for monitoring and control of geographically widespread processes. BS 7404-1.4 is intended as a brief tutorial on transmission techniques, equipment, and protocols in view of their use in telecontrol systems.
BS 7404-1.4 is thus intended as a guide to orient those using the standards defined in the series of IEC 870-5 and IEC 870-6. More precisely, BS 7404-1.4 gives a frame of reference for evaluating solutions as well as defining and describing the key technical terms. Terms that are defined in IEC 50(371) and in IEC 870-1-3 are complemented by further definitions in clause 3 of BS 7404-1.4.
BS 7404-1.4 on data transmission is useful for:
Telecontrol equipment and systems is an electronic device used to operate another device from a distance, usually wirelessly. BS 7404-1.4 provides descriptions of applicable basic communication technologies and basic rules as to how different system layers (see clause 3) can be used together (i.e., which combinations of standards in different layers are technically coherent and which are not). The basic classification of functions of a communication system follows that of the ISO seven-layer OSI model. BS 7404-1.4 is for descriptive purposes, and it is not required that a given system be actually implemented in this way. Within the IEC 870 series, the standards relating to telecommunication and telecontrol protocols are contained in part 5 (IEC 870-5) and part 6 (IEC 870-6). BS 7404-1.4 describes the contents and document organization of these two parts. BS 7404-1.4 purpose is to orient the potential user of these standards.
Part 5 specifies protocols conceived for systems requiring short reaction times in reduced bandwidth communication environments, often in the presence of harsh environmental conditions of electromagnetic interference, etc. An enhanced performance architecture (EPA) is used. Half-duplex and duplex protocols are specified that provide window size 1 for error recovery procedures. IEC 870-6 specifies functional profiles necessary for the telecontrol, automation and administration of electric power systems. They form a group of standards for communication in the overall communication network context. These profiles are completely within the framework of International Standards defined by ISO and CCITT. They are oriented toward, but not limited to, hierarchic and meshed networks and include error recovery procedures with arbitrary window size. Using BS 7404-1.4 you can specify telecontrol equipment and systems with coded bit-serial data transmission for monitoring and control of geographically widespread processes.
IEC 60870-1-4:1994