
APPENDIX
I. GLOSSARY
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Term Description
Group number Common number assigned to G codes having similar functions. For example,
group number 00 is assigned to one–shot G codes such as G04, G05 and
G45.
[H]
H code Coded number, following the H address, that specifies a tool offset number in
a machining center.
Helical interpolation Obtaining a path for moving the tool along a spiral by feeding another axis in
synchronization with circular interpolation.
Help function Displaying detail information relating to alarm detected by the CNC, or operat-
ing instructions for the CNC, on the screen.
High precision contour control The following functions, executed at high speed to eliminate machining error
due to post–interpolation acceleration/deceleration. (1) Pre–interpolation
error– free acceleration/deceleration based on multiple blocks read in
advance. (2) Smooth acceleration/deceleration in which changes in shape
and speed are accommodated and the allowable acceleration of the machine
is observed by reading multiple blocks in advance.
High–speed cycle cutting Converting a figure to be machined to a group of data items that can be dis-
tributed as high–speed pulses, saving the conversion results to memory, and
executing the CNC command to call the data group in a machining cycle.
High–speed machining function Executing preprocessing for a machining program before actual machining,
saving the preprocessing results into memory, and performing actual machin-
ing based on the preprocessing results retrieved from memory.
High–speed remote buffer Enabling the supply of a large amount of data to the CNC both at high speed
and continuously via a serial interface.
High–speed remote buffer A High–speed remote buffer for supplying movement data in binary.
High–speed remote buffer B High–speed remote buffer for supplying movement data as source code
created in an automatic programming unit.
HPCC mode Mode in which high–precision contour control (HPCC) is performed.
Hypothetical axis interpolation Distributing pulses by using one of circular interpolation axes as a hypotheti-
cal axis, thereby varying the feedrate of the controlled axis sinusoidally.
[I]
I/O channel Channel used to transfer data between input/output devices and the CNC.
Imaginary tool note Point defined on an imaginary axial straight line extending from the tip of a
tool. This makes it easier to set the tool to its start position or reference posi-
tion.
In–position State in which a servo motor is positioned to a point within a specified range
(previously set in the CNC).
Inch threading Precise threading in which the number of thread crests per inch is specified.
Inch/metric switching Selecting whether data is to be input in inch or metric units.
Increment system Generic term for least input increment and least command increment.
Incremental feed Feeding a controlled axis by a preset amount each time the corresponding
button is pressed.
Incremental programming Method by which an amount of tool movement (relative to the previous tool
position) is programmed.
Incremental value Distance or angle relative to the previous position.