PM858AK01 (3BSE082895R1) | ABB | CPU Board for AC 800M

Product Description

The PM858AK01 (3BSE082895R1) CPU board from ABB is a high-performance processing unit designed for the AC 800M controller family within the 800xA system. Built for redundancy and reliability, it provides fast cycle times, robust communication capabilities, and stable synchronization across distributed control environments.

Technical Specifications

• Processor: MPC866 embedded CPU

• Redundancy Switch-over Time: ≤ 10 ms

• Application Capacity:

• 32 applications per controller

• 64 programs per application

• 128 diagrams per application

• 32 tasks per controller

• Cycle Times:

• 32 configurable cycle times

• Minimum cycle time down to 1 ms

• Firmware Storage: 4 MB Flash PROM

• Power Supply: 24 V DC (range 19.2–30 V DC)

• Power Consumption: Typical 210 mA, maximum 360 mA

• Power Dissipation: 5.1 W (maximum 8.6 W)

• Redundant Power Input: Supported

• Backup Battery: Lithium 3.6 V

• Clock Synchronization: 1 ms accuracy via CNCP protocol

• Event Handling:

• Up to 3000 events per OPC client

• Transmission speed: 36–86 events/sec, 113–143 data messages/sec

• Communication Modules (CEX bus): Up to 12 modules, max 2.4 A supply current

• I/O Clusters:

• Non-redundant CPU: 1 electrical + 7 optical

• Redundant CPU: 7 optical

• I/O Capacity: Max 96 modules (single PM866) or 84 modules (redundant PM866)

• Modulebus Scan Rate: 0–100 ms (depending on I/O count)

• Electrical Modulebus Supply Current:

• 24 V: max 1.0 A

• 5 V: max 1.5 A

• Ethernet:

• 2 channels, IEEE 802.3 standard

• 10 Mbit/s, RJ-45 (8-pole female)

• Control Network Protocols: MMS and IAC

• Recommended Backbone: 100 Mbit/s switched Ethernet

• Real-time Clock Stability: 100 ppm (~1 h/year)

• RS-232 Interfaces:

• 2 ports (general + service tool)

• COM3 (non-redundant only): 75–19,200 baud, RJ-45, full RTS-CTS support

• COM4 (non-redundant only): 9,600 baud, RJ-45, opto-isolated, no RTS-CTS support

Application Scenarios

• Redundant CPU configurations for high-availability process control

• Large-scale distributed automation systems requiring fast cycle times

• OPC-based event handling in real-time industrial networks

FAQ

Q: What is the switch-over time in redundant mode?  A: The PM858AK01 achieves a maximum of 10 ms switch-over, ensuring minimal disruption.

Q: How many communication modules can be connected?  A: Up to 12 modules can be installed on the CEX bus.

Q: Is the CPU board suitable for high-speed I/O scanning?  A: Yes, it supports scan rates down to 1 ms, depending on the number of I/O modules.

Q: How does PM858AK01 compare to PM866?  A: PM858AK01 is optimized for redundancy and synchronization, while PM866 offers higher I/O capacity in single configurations.