Okuma OSP 5000, Электротехническое обслуживание, Учебное пособие

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Okuma America Corporation
MACHINE DEFINITION MACHINE DEFINITION
MACHINE DEFINITION MACHINE DEFINITION
MACHINE DEFINITION
Rev. 8-21-01
EEPROM (Electrically Erasable Read Only Memory) - Similar to the EPROM,
the stored information in an EEPROM can be erased by using a higher than
normal current rather than a UV light source. Because of this ability, the
EEPROM can be erased and new data stored while it is in the CNC control.
A new type of permanent memory device is appearing on some computers and CNC
controls which is referred to as “Flash Memory”. This device is also a nonvolatile
memory device. It is basically a combination of EPROM and EEPROM technology.
Flash memory has the advantage of having the physical size of the EPROM and the
quick erase capability of the EEPROM.
Long-Term Storage
There are certain types of data that need to be stored for a long period of time, but will
need to be changed or deleted periodically. Information such as part programs, param-
eters, tool offsets, etc. can be stored in this type of device. Two types of long term
memory storage devices currently being used on Okuma controls are C-MOS and Bubble
memory.
C-MOS Memory - This is a RAM (Random Access Memory) type device. Under
normal operating conditions this type of memory would lose the stored informa-
tion when power is shut off. A device that loses stored data when power is turned
off is said to be volatile. To prevent the loss of this information, a battery is
attached to the unit to maintain backup power in the event machine power is lost.
Bubble Memory - This is a non-volatile storage device. It does not lose informa-
tion when power is lost. Data is stored on tiny bubbles of a ferrous material that
is magnetized to represent the binary information. Large quantities of data can be
stored in a very small area. However, unlike C-MOS, the data must be read in a
set order (serially) which makes it slow in responding with information.
Temporary Storage
Some information is only needed once, or for a limited number of times, and then is
discarded. This type of information is stored in temporary memory. Active programs or
numbers that are continuously changing would fall into this category.
RAM - This type of memory is used to run the active programs such as the ma-
chine operating system or the active part programs. Once power is cut off to the
machine, this memory is lost. Okuma uses both D-RAM and S-RAM. D-RAM
stands for Dynamic Random Access Memory. Its memory is constantly being
refreshed. S-RAM stands for Static Random Access Memory. Its contents can be
saved by battery back-up.