Siemens 6DD1611-0AD0

Siemens 6DD1611-0AD0 is the MM11 coupling memory module for SIMADYN D subrack systems, providing 2 x 64 Kbyte RAM to enable data exchange between CPU modules. Installed between the first and second CPU module, this memory aids inter-CPU communication when more than one CPU module is present or when several CPUs access a CS7 serial interface. It supports both L-Bus and C-Bus connections, includes integrated bus termination for both buses, and offers power-failure resilience with data buffered by a back-up 3.4 V battery in the subrack. Additional hardware features include a system error-relay and a radio clock function, as described in Siemens SIMADYN D hardware specifications. The MM11 variant is identified by the order number 6DD1611-0AD0, with MM3 and MM4 variants offering the same form factor but different RAM capacities (MM3 2 x 64 KB, MM4 2 x 2 MB per bus).