Description
Detailed parameter table
| Parameter name | Parameter value |
| Product model | PM645B |
| Manufacturer | ABB |
| Product category | Programmable Logic Controller (PLC) central processing unit |
| Processor speed | 800 MHz |
| Memory capacity | 16 MB RAM, 32 MB flash memory |
| I/O capacity | Up to 8192 digital points, 4096 analog points |
| Communication ports | 2 x Ethernet (10/100/1000 Mbps), 1 x USB 2.0 |
| Supported protocols | PROFINET, Modbus TCP/IP, Ethernet/IP, BACnet/IP |
| Programming environment | Automation Builder |
| Operating voltage | 24 V DC ±10% |
| Power consumption | Max 15 W |
| Operating temperature | 0°C to 60°C |
| Protection rating | IP20 |
| Mounting type | DIN rail (35mm) |
| Dimensions | 100mm × 160mm × 60mm |
| Certifications | IEC 61131-2, CE, UL, ATEX |
ABB PM645B
Product introduction
The PM645B is a high-performance programmable logic controller (PLC) from ABB, designed to serve as the central processing unit in industrial automation systems. As a key component in ABB’s AC 500 PLC series, this controller combines powerful processing capabilities with flexible connectivity, making it suitable for medium to large-scale automation projects across various industries.
What sets the PM645B apart is its 800 MHz processor and expanded memory, which enable rapid execution of complex control algorithms and handling of large I/O configurations. With support for up to 8192 digital points and 4096 analog points, the PM645B can manage diverse automation tasks, from simple machine control to intricate process regulation. Its dual Gigabit Ethernet ports and compatibility with multiple industrial protocols ensure seamless integration with HMI systems, SCADA platforms, and other automation components. Whether deployed in manufacturing, water treatment, or energy production, the PM645B delivers reliable performance, enabling precise control and real-time data exchange in critical processes.
Core advantages and technical highlights
Powerful processing capabilities: The PM645B’s 800 MHz processor ensures fast execution of control logic, with a typical instruction cycle time of less than 10 nanoseconds. This speed is crucial for time-sensitive applications, such as synchronized conveyor systems in automotive plants, where milliseconds of delay can disrupt production sequences. The expanded memory (16 MB RAM, 32 MB flash) allows storage of large program files and historical data, supporting advanced features like trend logging and recipe management.
Flexible communication options: Equipped with two Gigabit Ethernet ports, the PM645B supports redundant network configurations, ensuring uninterrupted communication even if one network fails. It natively supports PROFINET, Modbus TCP/IP, Ethernet/IP, and BACnet/IP, eliminating the need for additional communication modules in mixed-protocol environments. For example, in a food processing plant, it can communicate with PROFINET-enabled sensors, an Ethernet/IP-based HMI, and a Modbus TCP SCADA system simultaneously, streamlining data flow across the entire facility.
Scalable I/O capacity: The PM645B can handle up to 8192 digital and 4096 analog points, making it suitable for scalable automation systems. This capacity allows plant operators to expand production lines without replacing the controller—simply adding I/O modules as needed. In a chemical plant, this scalability enables the controller to manage additional reactors or storage tanks as production demands grow, reducing long-term investment costs.
Robust industrial design: Operating reliably in 0°C to 60°C, the PM645B withstands the harsh conditions of industrial environments, including temperature fluctuations and electromagnetic interference. Its ATEX certification allows deployment in Zone 2 hazardous areas, such as paint booths or chemical storage facilities, without requiring additional enclosures. The controller’s compact DIN rail design saves space in control cabinets, while its low power consumption (max 15 W) reduces heat generation.
Typical application scenarios
In automotive assembly lines, the PM645B coordinates the operation of robotic welding stations, conveyor systems, and quality inspection sensors. Its fast processor ensures precise synchronization of robot movements with conveyor speeds, maintaining consistent weld quality. The controller’s dual Ethernet ports connect to a PROFINET network for real-time sensor data and an Ethernet/IP network for HMI visualization, allowing operators to monitor production metrics and adjust parameters on the fly.
In water treatment plants, the PM645B manages filtration systems, chemical dosing pumps, and flow control valves. It processes analog signals from pH and turbidity sensors (up to 4096 points) to regulate treatment processes, ensuring water quality meets regulatory standards. The controller’s Modbus TCP/IP connectivity sends operational data to a central SCADA system, while its flash memory logs historical trends for compliance reporting. Redundant network configurations prevent communication failures, critical for maintaining continuous water treatment.
ABB PM645B
Related model recommendations
PM650: A higher-performance variant of the PM645B with a 1.2 GHz processor and increased memory, ideal for large-scale process control.
PM630: A compact version of the PM645B with reduced I/O capacity, suitable for small machine control applications.
DI810 3BSE022369R1: A digital input module that expands the PM645B’s digital I/O capacity with 16 channels.
AI810 3BSE022368R1: An analog input module compatible with the PM645B for connecting 4-20 mA sensors.
CI854A 3BSE022469R1: A PROFINET interface module that enhances the PM645B’s network redundancy features.
AC500-eCo CPU PM564-R-T: An economy-range controller that works with the PM645B in distributed control architectures.
Panel 800 2CP202: An HMI panel that pairs with the PM645B for operator visualization and control.
Installation, commissioning and maintenance instructions
Installation preparation: Before installing the PM645B, ensure the DIN rail is securely mounted in a control cabinet with ambient temperature between 0°C and 60°C. Verify the 24 V DC power supply has a ripple of ≤50 mV to avoid processor interference. Use shielded Ethernet cables (Cat 5e or higher) for network connections, grounding the shield at both ends. Required tools include a torque screwdriver (0.5-0.8 Nm), wire strippers, and a laptop with Automation Builder software. Power off the cabinet during installation to prevent electrical damage.
Maintenance suggestions: Inspect the PM645B quarterly for dust accumulation and loose connections, cleaning with compressed air if necessary. Check Ethernet link status indicators monthly to ensure network connectivity. Backup the controller’s program and configuration weekly to prevent data loss in case of hardware failure. Update firmware annually using ABB’s Automation Builder to access performance improvements and new features. If the controller fails to communicate, check power and network connections first; reset to factory defaults if needed. Replace with an ABB-certified spare if hardware faults persist.
Service and guarantee commitment
The PM645B comes with a 5-year warranty from the installation date, covering manufacturing defects and ensuring compatibility with AC 500 series I/O modules. ABB guarantees replacement of faulty units within 48 hours for critical applications, minimizing downtime in automation systems. Technical support is available 24/7 via ABB’s global network of PLC specialists, offering assistance with programming, troubleshooting, and system integration. Extended service contracts include annual preventive maintenance, firmware updates, and priority support, ensuring the PM645B delivers reliable performance throughout its 10-year design lifespan. Customers also gain access to online resources, including programming guides, firmware updates, and compatibility matrices specific to this model.
