ABB Freelance DCS AC 900F high-end CPU (Plus version), 800 MHz, 48MB memory, supports redundancy and up to 1500 points of I/O, used for the core of small and medium-sized process control systems. 

I. Basic Information

Model: PM904F

Order Number: 3BDH001002R0001

Series: Freelance DCS / AC 900F (Plus)

Type: Redundant CPU Module (Controller Core)

Installation: AC 900F Rack, 24VDC Power Supply

Core Technical Parameters

Processor: PowerQUICC II Pro (32-bit RISC), 800MHz

Memory: 48MB Total RAM (16MB Battery Buffer SRAM + 32MB DRAM)

Storage: SD Card Slot (Backup / Firmware Upgrade)

Real-time Performance: Minimum 5ms for periodic tasks; Redundant Switching 500ms

I/O Capability: Direct connection up to 10 S700 I/O Modules; Total I/O Capacity 1500 Points

Communication Interfaces:

4×100Mbps Ethernet (Modbus TCP, IEC 60870-5-104, OPC UA)

2×Serial Ports (RS-232/485, Modbus RTU, IEC 60870-5-101)

1×Diagnostic Serial Port (RS-232, D-SUB)

4×Communication Expansion Slots (PROFIBUS/CAN, etc.)

Power Supply: 24VDC, Working Current 1A, Power Consumption 18W (Full Configuration 24W)

Battery Backup: Lithium Battery, Data Retention > 2 Years at 40°C, Low Battery Warning 14 Days

Environment: Operating Temperature -20°C to +70°C; Storage Temperature -40°C to +85°C IP40

Dimensions / Weight: 220×180×130mm / Approximately 1.1kg

Key Functions

High-performance Control: 800MHz + 48MB memory, capable of handling complex circuits and multiple tasks, suitable for process automation.

Full Redundancy Design: CPU / Communication / Power redundancy, 500ms uninterrupted switching to avoid single-point failure shutdown.

Multi-protocol Interconnection: 4 Ethernet + 2 Serial Ports + Expansion Slot, seamless connection with DCS, PLC, SCADA and fieldbus.

Convenient Maintenance: SD card one-click backup / restoration; LCD display (optional); firmware online upgrade.

System Integration: Combined with Freelance Control Builder, supports IEC 61131-3 and graphical programming.

Typical Applications

Power: Power plant boiler / turbine control, substation integrated automation.

Petrochemical: Refining and chemical plants, compressors, reactors advanced control.

Water Treatment: Whole process monitoring and interlock for sewage / water treatment plants.

Metallurgy / Construction Materials: Continuous casting, rolling lines, cement kilns process control.