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RAM (RANDOM ACCESS MEMORY). This type memory is random because it provides access to any storage location point in the memory immediately by means of vertical and horizontal co-ordinates. Information may be "written'' in or "read'' out in the same very fast procedure.
RANDOM ACCESS. (1) Access to a computer storage under conditions whereby there is no rule for predetermining the position from where the next item of information is to be obtained. (2) Describes the process of obtaining information from or placing information into a storage system where the time required for such access is independent of the location of the information most recently obtained or placed in storage. (3) Describing a device in which random access can be achieved without effective penalty in time.
RANDOM TOOL SELECTION. A feature allowing the next tool to be loaded from any position in an automatic toolchanger rather than from the next location in the changer.
RAPID TRAVERSE. Tool movement at a maximum feed rate from one cutting operation to another.
READ-ONLY MEMORY (ROM). Digital storage device that can be read from but cannot be written into by the computer. The ROM is used to store the microprogram or a fixed program depending upon the micro-programmability of the CPU. The microprogram provides the translation from the higher-level user commands, such as ADD, SUBTR, etc., down to a series of detailed control codes recognizable by the microprocessor for execution. The size of the ROM varies according to user requirements within the maximum allowed capacity dictated by the addressing capability of the microprocessor.
READ OUT. The presentation of output data by means of visual displays, punched tape, etc.
REAL TIME. The ability of a computer to function and control a process as the process occurs. (1) In solving a problem, a speed sufficient to give an answer within the actual time the problem must be solved. (2) Pertaining to the actual time during which a physical process transpires. (3) Pertaining to the performance of a computation during the actual time that the related physical process transpires in order that results of the computation can be used in guiding the physical process.
RECTANGLAR COORDINATES. A system of two or three mutually perpendicular axes along which any point can be located in terms of distance and direction from any other point.
REED SWITCH. Refers to a special switching device which consists of magnetic contactors which are sealed into a glass tube. The contactors are actuated by the magnetic field of an external solenoid, electromagnet, or a permanent magnet.
RELAY. An electromagnetic switching device in which contacts are opened and/or closed by variations in the conditions of one electric circuit and thereby affect the operation of these devices in the same or other electric circuits.
REMOTE CONTROL. Any system of control performed from a distance. The control signal may be conveyed by intervening wires, sound (ultrasonics), light, or radio.
REPEATABILITY. The closeness of agreement among a number of consecutive measurements of a constant signal, approached from the same direction.
RESOLUTION. (1) The smallest incremental step in separating a measurement into its constituent parts. In a digital system, resolution is one count in its least significant digit. (2) The ratio of maximum to minimum readings of a measuring system. (3) The process of separating the parts which compose a mixed body.
RESOLVER. (1) A means for resolving a vector into two mutually perpendicular components. (2) A transformer, the coupling between primary and secondary of which can be varied. (3) A small section with a faster access than the remainder of the magnetic-drum memory in a computer. (4) A device which separates or breaks up a quantity, particularly a vector, into constituent parts or elements; e.g., the mutually perpendicular components of a plane vector. (5) A small section storage, particularly in drum, tape, or disk storage units that has much faster access than the remainder of the storage.
RESPONSE TIME. (1) The time (usually expressed in cycles of the power frequency) required for the output voltage of a magnetic amplifier to reach 63% of its final average value in response to a step-function change of signal voltage. (2) The time required for the pointer of an instrument to come to apparent rest in its new position after the measured quantity abruptly changes to a new constant value. (3) The amount of time elapsed between generation of an inquiry at a data communications terminal and receipt of a response at that same terminal. Response time, thus defined includes: transmission time to the computer, processing time at the computer, including access time to obtain any file records needed to answer the inquiry, and transmission time back to the terminal.
RETROFIT. Modification of a machine originally operated by manual or tracer control to one that operates by NC controls.
ROBOT. A robot is a reprogrammable, multifunctional manipulator designed to move material, parts, tools, or specialized devices through variable programmed motions for the performance of a variety of tasks.
ROUTINE. A series of computer instructions which performs a specific application function.
RS-232C. Electronic Industries Association (EIA) standard for data communications, RS-232 type C. Data is provided at various rates, 8 data bits per character. Refers to the interface between a modem and the associated data terminal equipment. It is standardized by EIA Standard RS 232. For voice-band modems the interface leads are single leads with a common ground return. Polar type signals are specified with a minimum amplitude of +3 V at the terminating end. The maximum allowable voltage is +25V. A ground potential difference between equipment of up to 2V is allowed for by specifying that the driver sources must provide a +5V signal. The terminating impedance is required to be in the 3000-7000 ohm range. The drivers typically provide voltages in the range +6V to +10V with a source impedance of a few hundred ohms. A negative polarity indicates the binary state "1'', marking, or an OFF control state. The positive polarity indicates the binary state "0'' spacing, or an ON control state.
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