Telemechanic System

(telemekhanicheskaia sistema), a group of apparatus and devices used to transmit commands from an operator or control computer over a distance to controlled systems through radio channels or wire lines or to transmit monitoring information in the opposite direction. A telemechanic system would generally be called a remote-control system in English. In the present article, however, the term “remote-control” is used in a narrower sense; the term “telemechanic,” as used here, is similar in meaning to the English term “remote-control” in its broadest sense (see and ).

A telemechanic system includes the following: a control center, where the operator is located; one or more controlled points, where the controlled or monitored systems are located; and communication links (data transmission channels) connecting the control center with the controlled points. Complex telemechanic systems may have more than one control center; the control centers may be on an equal footing or may be hierarchically organized.

A distinction is made between telemechanic systems for controlled systems that are associated with a single controlled point and telemechanic systems for controlled systems that are dispersed—that is, are grouped around several controlled points or are scattered individually over a large area. An example of a telemechanic system of the first type is the control system of a construction crane, an aircraft, or a pumping station. Typical examples of the second type of telemechanic system are, when control is accomplished from a single control center, the control systems of gas pipelines, oil pipelines, power systems, railroad terminals, mines, and factories.

In a telemechanic system, the information on the condition and parameters of the controlled systems that is received at the control center is usually presented to a human operator. On the basis of this data, he makes decisions and issues control commands. The control center has (1) a control panel equipped with appropriate devices for displaying the monitoring information and (2) a control console with devices for controlling the telemechanic equipment (for example, toggle or push-button switches) and for forming the signals sent to the controlled systems. When the amount of information that must be handled is large, the processing of the information and its conversion to the form most convenient for decision-making by the operator are carried out by automatic devices or an electronic computer.

A telemechanic system may transmit all or just certain types of monitoring and control information. When only information on the values of the parameters of the monitored systems is transmitted, the telemechanic system is called a telemetering system. In a remote-signaling system, the transmitted information is concerned primarily with which of the possible states, or conditions, the monitored system is in; usually there are two such conditions. In a remote-control system, only control commands are transmitted. In some telemechanic systems, information of more than one type may be transmitted—for example, measurement and signaling information (see) or control and signaling information (see). There also exist systems in which monitoring and control information of all types is transmitted (see).

The principal features by which a telemechanic system may be characterized are as follows: functions performed, types of information handled, arrangement of controlled systems, range of operation, number of controlled systems, range of operation, number of controlled systems, speed, accuracy of data transmission, reliability, structure, and type of communication channels.

In the simplest case, the equipment of a telemechanic system consists of transmitting and receiving subassemblies that effect the transmission of telemechanic information. Telemechanic systems often include automatic devices that facilitate the operator’s work or increase the reliability and efficiency of the transmission of information through the communication channels. Such devices may make possible, for example, the cyclic interrogation of controlled systems, the transmission of commands according to a preassigned program, the comparison of the values of monitored parameters with the prescribed values, and the diagnosis of damage. A telemechanic system is a complicated set of equipment comprising diverse instruments and devices. The number of different components may reach tens or hundreds of thousands.

In the early 20th century, which was the initial period of development of telemechanics, the apparatus used in telemechanic systems was primarily of the relay-contact type. In the 1950’s, relay-contact apparatus was supplanted by, for example, magnetic and semiconductor noncontact elements. The 1970’s have seen the introduction of microelectronic elements and the modular method of constructing telemechanic systems. The modular system of telemechanic equipment developed in the USSR embraces (1) a set of standardized functional units made with integrated circuits and (2) a number of telemechanic devices constructed from these units. The Soviet modular system of telemechanic equipment is part of the State System of Industrial Instruments and Automation (GSP).