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Okuma America Corporation
MACHINE DEFINITIONMACHINE DEFINITION
MACHINE DEFINITIONMACHINE DEFINITION
MACHINE DEFINITION
Rev. 8-21-01
Disk Drives
A floppy disk drive is constructed similar to a record player. A platter or disk coated
with a ferrous material is rotated while a read/write head is moved over the surface and
magnetizes the ferrous material in patterns representing binary data. Data is stored in
concentric circles on the surface of the disk. Each circle is referred to as a track. Each
track can be divided into a number of sectors. When data is written on the disk, the head
actuator pushes or pulls the read/write head over the surface of the disk until it is aligned
with the proper track. The sectors are then searched until the proper location is found to
read or write the data.
On a hard disk drive, the head floats above the surface of the platter. If it were to come
into contact with the disk surface, or if some form of contamination were to get between
the read/write head and the disk, it would cause damage to the ferrous material.
Technically, tape readers and disk drives are also referred to as permanent storage de-
vices.
RS-232 Interface
Data is sometimes generated or stored using a device that is not a part of the CNC
control, i.e., external disk drive, PC (Personal Computer), main frame computer,
etc. This data can then be transferred from the external device to the CNC control
via an RS-232 port. This port can also be used for DNC (Direct Numerical
Control) communications. DNC has several levels of operation. In its simplest
form it transfers data from an external device to the CNC control. In some appli-
cations it has the capability of transferring all control of the machine to an exter-
nal computer.
External Switches
The simplest form of an I/O device is the external switch. Examples of input
devices are limit switches, proximity switches, pressure switches, etc. Relays,
solenoids, LED’s, and lamps are examples of output devices.
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