29
RAM and EEPROM Cards Data
can be randomly written to and read from RAM or EEPROM Cards, making
it possible to easily stored programs. The memory of a RAM Cards is erased,
however,
when power is not supplied to
the CPU or when the RAM Card is re
-
moved from the CPU without first being connected to a backup battery. EE-
PROM
Cards cannot be written while mounted in the CPU. Data can be written
to
RAM Cards while they are mounted in
the CPU by using the CVSS or by in
-
structions in the user program.
Both the RAM and EEPROM Memory Cards are equipped with write-protect
switches.
Setting the write-protect switch to ON
prevents data from being written
to
or erased from the Card. Setting the write-protect switch to OFF allows data
to
be written to or erased from the Card.
ON
OFF
Four
RAM Memory Card models are available, varying in memory capacity from
8K,
16K, 32K to 64K words. T
wo EEPROM Memory Card models are available,
one containing 8K words of memory and the other 16K words of memory.
RAM Card Backup Battery Insert a battery into a RAM Memory Card before mounting the Card into the
CPU.
Leave the battery in its
holder
. Battery life expectancies are given below
.
Replace the battery within the time listed. Refer to
Section 4 Inspection and
Maintenance
for the battery replacement procedure.
Card Capacity Life
HMC-ES641 64K bytes 5 years
HMC-ES151 128K bytes 2 years
HMC-ES251 256K bytes 1 year
HMC-ES551 512K bytes 6 months
EPROM Cards Data
contained in the ROM Card is stored on EPROM
chips and cannot be al
-
tered
or erased during the CPU’
s operation. The EPROM chip is mounted to the
Memory
Card and
the entire pack is installed in the CPU. Once data is written to
the chip, the data will not be lost when the power to the PC is OFF.
ROM
Cards are shipped unprogrammed. The ROM Card can be programmed
using a CV500-MCWjj Memory Card Writer.
The procedure for erasing EPROM Memory Card data is as follows:
1, 2, 3...
1. Open the memory card cover by pressing at an angle on the catch at the
bottom edge of the card using a pointed object, such as a pen.
2. Erase the data from the EPROM chips by exposing the window of the
EPROM
chips to ultraviolet light. Any of a number of commercially
available
EPROM erasers may be used. To ensure complete erasure, the Memory
Card
should be subject to a minimum exposure as specified by the eraser
manufacturer.
3. Close the cover and slide the catch back into place.
Rack Components Section 2-3
To Next Page
Need help?
General
