The GE-Emerson IC697MEM717 Series 90-70 CMOS Expansion Memory may be used to expand logic and data memory in either the CPU 771 (IC697CPU771) and CPU 772 (IC697CPU772) modules, or the Programmable Coprocessor Module (IC697PCM711). It is installed as a daughter board and resides in the same slot as the module it serves. Memory on this board supplements memory available on the baseboard.
Memory is retained in the event of power loss by the battery on the base board housing. Logic program memory is continually error-checked by the PLC CPU as a background task. The PCM error checks storage memory when power is cycled and on hard or soft resets.
