6ES5304-3UA12
Siemens Simatic S5 IM304 Interface Module

Designed to be the direct replacement to the Siemens 6ES5304-3UA11, the 6ES5304-3UA12 enabled the S5-115U series PLC to interface with expansion modules up to 600 meters away.  The interface module is often referred to as the IM 304 modules however this covers both the 3UA11 and the 3UA12. 

The IM 304 interface module is plugged into the central controlller (CR 700-0LB, CR 700-2, CR 700-3). Up tp two times four expansion units (with power supply module) can be connected in distributed configuration to one IM 304 interface module.  The central controller and the distributed expansion unit can be expanded with up to three additional expansion units (ER 701-0 and ER 701-1 subracks) connected in a centralized configuration. Up to four areas of 256 bytes each in the Simitac S5-115U programmable controller can be addressed with the 6ES5 304-3UA12 interface module.