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SCANNER. Refers to an instruction which automatically samples or interrogates the state of various processes, files, conditions, or physical states and initiates action in accordance with the information obtained.
SCRAP ALLOWANCE. The factor that expresses the quantity of a particular component that is expected to be scrapped while that component is being built into a given assembly. Also a factor that expresses the amount of raw material needed in excess of the exact calculated requirement to produce a given quantity of a part. The factor, dependent upon the type of assembly or part, is carried in the product structure segment and is used to increase the requirements as the component requirements are exploded.
SENSITIVITY. (1) Ratio of the response of a measuring device, to the magnitude of the measured quantity. It may be expressed directly in divisions per volt, milliradians per microampere, etc., or indirectly by stating a property from which sensitivity can be computed (e.g., ohms per volt for a stated deflection). (2) The degree of response of an instrument of control unit to a change in the incoming signal.
SENSOR. A transducer or other device whose input is a quantitative measurement of an external physical phenomenon and whose output can be monitored by a computer or other control system.
SEQUENTIAL LOGIC. Refers to a circuit arrangement in which the output state is determined by the previous states of the input.
SERVOMECHANISM. 1. A power device for affecting machine motion. It embodies a closed-loop system in which the controlled variable is mechanical position and velocity. (2) Closed-cycle system in which a small input power controls a much larger output power, e.g., movement of a gun turret may be accurately controlled by movement of a small knob or wheel.
SET POINT. In a feedback control loop, the point which determines the desired value of the quantity being controlled.
SHOP FLOOR CONTROL. A system for utilizing data from the shop floor as well as data processing files to maintain and communicate status information on shop orders and work centers. The major subfunctions of shop floor control are: (a) Assigning priority to each shop order. (b) Maintaining WIP quantity information for MRP. (c) Conveying shop order status information to the office. (d) Providing actual output data for capacity control purposes. (cf. Closed-loop MRP)
SIGNAL. (1) A visible, audible, or other conveyor of information. (2) The intelligence, message, or effect to be conveyed over a communication system. (3) A signal wave. (4) The physical embodiment of a message.
SOFTWARE. All of the program manuscripts, tapes, decks of cards, methods sheets, flow charts, and other programming documentation associated with computers and numerical control systems. Its counterpart is the physical hardware comprising the computer or NC system.
SOFTWIRED. A system in which a computer generates control logic, as determined by a software program.
SOLID STATE. Pertaining to an electrical circuit having no moving parts, relays, vacuum tubes, or gaseous tube components.
SPECIFICATION. A clear, complete, and accurate statement of the technical requirements descriptive of a material, an item, or a service, and of the procedure to be followed to determine if the requirements are met.
STAND-ALONE SYSTEM. A complete operational system that does not require support from other devices or systems.
STANDARD. An acceptance criterion or an established measure for performance, practice, or design.
STATIC BEHAVIOR. The behavior of a control system or an individual unit under fixed conditions (as contrasted to dynamic behavior, under changing conditions).
STEADY STATE. A condition in which only negligible change is evident with time.
STEP 7. A turning processor language that develops machining data from the descriptions of the rough stock and the finished workpiece.
STEPPING MOTOR. A bidirectional, permanent magnet motor which turns through one angular increment for each pulse applied to it. Refers to one in which rotation occurs in a series of discrete steps controlled electromagnetically by individual (digit) input signals.
STORAGE. Pertaining to a device into which data can be entered, in which they can be held, and from which they can be retrieved at a later time.
STRAIGHT-CUT SYSTEM. A system which has feed rate control only along the axes and controlled cutting action that occurs only along a path parallel to the linear (or circular) machine ways.
SUBASSEMBLY. Two or more parts joined together to form a unit which is only a part of a complete machine, structure, or other article.
SUBROUTINE. A portion of an NC program, stored in memory and capable of being called up to accomplish a particular operation. It reverts to the master routine upon completion.
SURFACE. A geometric shape used for controlling the location of a tool in space. As a cutter is directed along a path, it is guided by two surfaces from the programmer's viewpoint. One is called the part surface. Generally, the bottom of the cutter moves along the part surface while the side of the cutter is guided by the drive surface. A third surface, the check surface, is used to check or halt the movement of the tool in its progress along the DS-PS pair.
SYSTEM. An organized collection of interdependent and interactive personnel, machines and methods combined to accomplish a set of specific functions as a larger unit having the capabilities of all the separate units.
SWITCH. A mechanical or electrical device that completes or breaks the path of the current or sends it over a different path.
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