
7. TROUBLESHOOTING
B–63175EN/03
452
An ECC error occurred in the SRAM that contains data such as
parameters and machining programs.
This error occurs when the battery mounted on the faceplate of the base
printed–circuit board becomes weak or when data stored in the SRAM is
destroyed by an external cause. Alternatively, this error may be due to a
failure in the memory module or base printed–circuit board.
The ECC check method is a method of checking data stored in the SRAM.
This method is employed in place of the conventional parity check.
With the ECC check method, 8–bit correction data is provided for 16–bit
data. If a data error occurs in any bit of the 16 bits, the error is
automatically corrected by the correction data, and the CNC operation can
be continued. This alarm is issued when a data error occurs in more than
one bit.
With the conventional parity check method, even a single–bit data error
resulted in a system alarm.
The battery is rated at 3 V. If the battery becomes weak, causing a voltage
drop to Typ 2.5 V (2.3 V–2.7 V), a battery alarm is issued, and “BAT”
displays on the screen.
If a battery alarm is issued, replace the battery with a new one as soon as
possible.
NOTE
The battery is a consumable.
Perform memory all–clear operation to start the CNC. Alternatively,
when there is already a backup copy of SRAM data, restore the data. Use
the boot system for SRAM data backup and restoration.
If the alarm still exists after memory all–clear operation or backup data
restoration, replace the memory module.
After replacing the memory module, perform memory all–clear operation
to start the CNC. In this case, all data must be set again.
When there is backup data, restore the data then start the CNC.
If the alarm still exists even after the above action is taken, replace the
printed–circuit board.
7.27
ALARM 935
(SRAM ECC ERROR)
Causes and Remedies
D ECC check
D Battery check
D Attempting memory
all–clear operation
D Replacing the memory
module
D Replacing the base
printed–circuit board