SRAM Disk

The SRAM disk is a battery-buffered, nonvolatile RAM disk located in the SRAM and can be used for any application purpose. If a battery is inserted into the Processor Module, the data stored in the SRAM disk will not get lost during a power-down cycle. During PLC startup, the SRAM disk will be formatted automatically if no or an empty battery is inserted into the Processor Module. In this case, the PLC issues an E4 error (#0153286827 = [4-9-34-31-2-43], i.e. SRAM disk has been formatted). To enable the visibility of errors, set the CPU parameter Check for battery to TRUE. With this, the system will signal errors during the formatting of the SRAM disk.

Size	Product specific, see table Memory Sizes Introduction of AC500 Storage Devices for AC500 Products
IEC access	CAA_File_Library: CAA_File Library
Diagnosis device number	34