Schneider ALU286 Central Processing Unit

Technical Specifications

Parameter	Value
Brand	Schneider
Model	ALU286
Category	Central Processing Unit
Weight	0.86 lbs (0.39 kg)
Dimensions	4.7 x 3.9 x 3.2 inches
Component Count	188 discrete components
Processor Type	16-bit microprocessor
Clock Speed	16 MHz
Program Memory	128 KB EPROM
Data Memory	32 KB static RAM
Backup Memory	8 KB EEPROM
Processing Speed	1.2 µs per boolean instruction
Communication Ports	1 x RS-232, 1 x RS-422
Digital I/O Capacity	256 points max
Energy Storage	4 x 100µF, 2 x 47µF
Backup Battery	3.6V lithium (3 years life)
Operating Temperature	0°C to 55°C

Physical Construction and Component Layout

This ALU286 central processing unit measures 4.7 inches in height. Its width reaches 3.9 inches with a depth of 3.2 inches. The total weight comes to approximately 0.86 pounds. Manufacturers placed 188 discrete components on this multi-layer PCB. These components include a 16-bit CPU, memory ICs, bus controllers, and clock oscillators. The board uses plated through-hole technology for durability.

Processing Architecture and Memory Resources

ALU286 features a 16-bit microprocessor running at 16 MHz. This CPU executes boolean instructions in 1.2 microseconds each. Program memory consists of 128 KB of EPROM for firmware storage. Data memory provides 32 KB of static RAM for variables and registers. An additional 8 KB of EEPROM holds configuration parameters permanently. A 3.6V lithium battery backs up the static RAM contents. This battery maintains data for approximately three years. Consequently, the processor retains critical information during power outages.

Communication Interfaces and I/O Capacity

The central processing unit includes two onboard communication ports. One RS-232 port connects to programming terminals or HMIs. One RS-422 port supports long-distance links up to 1200 meters. The ALU286 manages up to 256 digital I/O points total. You can add remote I/O racks using the RS-422 network. For energy storage, the board integrates four 100µF capacitors. Two additional 47µF capacitors filter high-frequency power noise. These capacitors smooth voltage fluctuations from the backplane supply.

Application Use and System Reliability

You will find this processor in older Schneider PLC systems. It suits conveyor control, packaging lines, and material handling. The ALU286 operates reliably from 0°C to 55°C ambient. A watchdog timer resets the CPU if software execution stalls. Therefore, this central processing unit delivers dependable logic control for legacy industrial automation.