An ECC error occurred in the SRAM used to store data such as parametersand machining programs.

This alarm is issued if the battery has run down or if the data in the SRAMis destroyed due to some external cause. Or, the FROM/SRAM module or main board may be defective

ECC check
This is the method of checking the data stored in the SRAM. It has beenemployed instead of the conventional parity check.
With the ECC check method, 8–bit correction data is provided for 16–bitdata, so that if a data error occurs in one of these 16 bits, the error isautomatically corrected with the correction data, allowing the CNC tocontinue 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.

Checking the battery
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.


Performing memory all clear
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.

Replacing the FROM/SRAM module
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.

Main board
If any of the above actions does not solve the problem, replace the mainboard.
See Section 2.4, “CONNECTOR AND CARD CONFIGURATIONS OFPRINTED CIRCUIT BOARDS” for an explanation of the mounting
locations of the cards.

Reference book
Fanuc Series 0i-Model A Maintenance Manual B-63505EN/02