ALU-252
AEG Processor Module

The module ALU 252 contains the processor (CPU) of the A120 with an integrated communication port for the Modnet 1/SFB, via which it can be connected as a slave to a superior controller (master). Together with the power supply DNP, the ALU generates an internal I/O bus (modified
PAB1). The ALU 252 can only be inserted in slot 0 (left of the power supply) in the backplane DTA 200.

The module consists of 3 PCBs which are assembled in a 2-slot size module with 16T construction width and 3HE construction height. They are connected using ribbon cable and bus planes. The essential components of the modules are

• Micro-processor
• 32 KB EPROM for basic software
• 32 KB RAM for signal memory and system variables
• 64 KB RAM for user program and organization data (approx. 12 k instructions)
• Real time clock with date functions and calendar functions
• Front slot for EPROM card (PC 001)
• Battery compartments for 2 back-up batteries
• DIP switch for starting mode and start behavior
• Front port for programming panel (RS 232C)
• 3 rear ports for I/O bus (modified PAB1)21 ALU 252 39
• DIP switch for slave address and transmission rate
• Front port for Modnet 1/SFB networking (RS 485)