Schneider PCALU201L Compact CPU Module

This compact CPU module serves as the processor for Modicon M221 logic controllers. It executes control programs and manages all integrated I/O channels. You can deploy this unit for small machine control and standalone automation applications.

Technical Specifications

Parameter	Value
Model	Schneider PCALU201L
Category	Compact CPU Module
Processor Type	ARM Cortex-M3, 32-bit
Processor Speed	24 MHz
User Program Memory	128 KB Flash
Data Memory	16 KB RAM
Local I/O Points	14 discrete inputs + 10 discrete outputs
Discrete Input Type	8 fast inputs (4 as interrupts) + 6 standard
Discrete Output Type	10 transistor sinking outputs
Output Current per Point	0.3 Amps maximum
Built-in Communication Ports	1 x RS-232 (non-isolated), 1 x RS-485
Protocol Support	Modbus RTU (master/slave)
Real-Time Clock	Yes (with battery backup)
Power Supply	24 VDC ±20%
Power Draw	200 mA typical
Dimensions (W x H x D)	9.0 cm × 7.0 cm × 6.5 cm
Weight	0.35 kg (0.77 lbs)
Connector Type	Removable screw terminals for I/O + 2 x RJ45
Component Count	1 main board + 1 processor chip + 24 I/O points + 2 communication ports + 24 LEDs
Energy Storage	220 µF hold-up capacitor + lithium battery (240 mAh) for RTC
Interrupt Response Time	50 microseconds typical

Processing Power and Memory

The Schneider PCALU201L runs a 24 MHz ARM Cortex-M3 processor for fast logic execution. You get 128 KB of Flash memory for storing user programs and configuration. An additional 16 KB of RAM holds runtime variables and system data. The CPU executes Boolean logic at approximately 0.2 microseconds per instruction.

Integrated I/O Configuration

This compact unit includes 14 discrete inputs and 10 transistor outputs on board. Eight inputs operate as fast counters at up to 5 kHz. Four of these inputs also serve as hardware interrupts for immediate response. Ten transistor outputs switch loads up to 0.3 Amps per point at 24 VDC.

Communication Capabilities

A built-in RS-232 port connects to HMIs or programming laptops directly. A separate RS-485 port supports Modbus RTU networking with up to 247 slaves. The CPU can act as either a Modbus master or slave on both ports. Therefore, you can integrate this unit into existing Modbus systems seamlessly.

Real-Time Clock and Energy Backup

A lithium battery maintains the real-time clock for up to 3 years without external power. The 220 µF capacitor provides short-term hold-up during battery replacement. The RTC supports time-stamped alarms and scheduled control tasks. Consequently, you get accurate time-based control without an external time source.

Installation and Wiring

Mount this CPU onto standard 35 mm DIN rail inside a control cabinet. Removable screw terminals simplify field wiring and module replacement. For best results, use separate conduits for input and output wiring. The compact 90 mm width saves valuable panel space for small machines.

Visual Status Indication

Twenty-four LEDs provide real-time status for every I/O channel. Green LEDs show the ON/OFF states of all 14 inputs. Red LEDs illuminate when their corresponding transistor outputs energize. Additional LEDs indicate power, run status, and communication activity.

Why Choose This CPU Module

This compact processor fits perfectly into small machinery applications. Its integrated I/O eliminates separate modules for simple control tasks. Therefore, manufacturers choose this unit for packaging equipment, conveyors, and small assembly machines.