Siemens · SIMATIC S7-400 Siemens 6ES7952-1AM00-0AA0 RAM Memory Card 6ES7952-1AM00-0AA0 is a Siemens SIMATIC S7-400 RAM memory card in the long design, with a memory capacity of 4 Mbyte. It is used to expand the CPU load memory in an S7-400 automation system. The RAM card is installed in the CPU memory-card slot and is loaded using a programming device. Unlike a Flash card, it does not retain its contents when removed from the CPU; backup power is required to retain its