
7. TROUBLESHOOTING
B–63665EN/01
332
An ECC error occurred in the SRAM used to store data such as parameters
and machining programs.
This alarm is issued if the battery has run down or if the data in the SRAM
is destroyed due to some external cause. Or, the FROM/SRAM module
or motherboard may be defective.
This is the method of checking the data stored in the SRAM. It has been
employed instead of the conventional parity check.
With the ECC check method, 8–bit correction data is provided for 16–bit
data, so that if a data error occurs in one of these 16 bits, the error is
automatically corrected with the correction data, allowing the CNC to
continue operation. This alarm is issued if a data error occurs in two or
more bits.
With the conventional parity check method, a system alarm is issued if a
data error occurs even in one bit.
The battery is rated 3 V. A battery alarm is issued and “BAT” flashes on
the screen if the voltage of the battery drops to 2.6 V.
If a battery alarm is issued, replace the battery with a new one promptly.
Perform a memory all clear operation, then start up the CNC.
Alternatively, if a backup of the data in the SRAM has been made, use the
backup to restore the data. To back up and restore the data in the SRAM,
use the boot system.
If memory all clear or the restoration of the data with a backup does not
solve the problem, replace the FROM/SRAM module. Take a backup
copy in advance. All the software must be restored after the replacement.
After replacing the FROM/SRAM module, perform a memory all clear
operation and start up the CNC. All the data must be re–loaded.
If a backup is available, restore the data using the backup, then start up
the CNC.
If any of the above actions does not solve the problem, replace the
motherboard.
7.29
ALARM 935
(SRAM ECC ERROR)
Causes and actions
D ECC check
D Checking the battery
D Performing memory all
clear
D Replacing the
FROM/SRAM module
D Motherboard