The 1794-TB3G is a Terminal Base module manufactured by Rockwell Automation as part of their Allen-Bradley 1794 Flex I/O series. It is a terminal base designed to hold and provide connections for I/O modules within a Rockwell PLC system.

Here are some key features of the 1794-TB3G Terminal Base module:

- It allows for easy installation and maintenance of I/O modules in a PLC system.

- The module provides a backplane interface to connect I/O modules, facilitating communication between the modules and the PLC controller.

- It features a compact and modular design, enabling flexible expansion and efficient use of space in the control panel.

- The 1794-TB3G supports various I/O module types, including digital input/output, analog input/output, and specialty modules for specific control functions.

Regarding the 1794-IE12 module, it is an analog input module rather than a memory controller. The 1794-IE12 is a Rockwell Automation module that provides 12 channels of analog input signal conditioning for voltage and current inputs in a PLC system.