ABB PM861AK01 3BSE018157R1 Processor Unit

The ABB PM861AK01 3BSE018157R1, also cataloged as the PM861A Processor Unit, operates as a dedicated hardware component for central processing unit execution and modular control tasks within ABB AC 800M platforms.

Hardware Specifications

Backplane Bus Communication Velocity & I/O Density

The processor module manages system data traffic across the CEX-Bus backplane extension and ModuleBus interfaces, maintaining backplane bus communication velocity across expanded controller configurations. In single CPU deployments, the unit supports up to 96 I/O modules, while scaled redundant architectures accommodate up to 84 I/O modules. Dual CPU setups execute bumpless state synchronization across the RCU-Link interface, guaranteeing failover execution within 10 ms. Direct memory mapping accommodates up to 32 applications, 64 programs, and 32 concurrent control tasks with execution cycle rates down to 1 ms.

Frequently Asked Questions

Q: What items are included in the complete PM861AK01 processor unit kit?

A: The PM861AK01 kit contains the PM861A CPU module, a TP830 baseplate, a TB850 CEX-bus terminator, a TB807 ModuleBus terminator, a TB852 RCU-Link terminator, and a 3.6 V lithium backup battery.

Q: How does memory retention work during a main power interruption?

A: An internal 3.6 V lithium backup battery preserves application program code and user dynamic data stored inside the 16 MB RAM array when the external 24 VDC supply voltage drops below operational thresholds.

Q: What are the functional differences between serial ports COM3 and COM4?

A: Serial port COM3 provides standard RS-232C communications with full modem control signals, whereas serial port COM4 provides galvanic isolation specifically dedicated to connecting local configuration and software commissioning tools.

Field Installation Guidelines

Mount the TP830 baseplate firmly onto a standard DIN rail before locking the PM861A CPU unit into place using the integrated slide-lock mechanism. Ensure the grounding metal clip makes direct, low-resistance contact with the rail to establish protective chassis earthing.

Install the required bus terminators (TB850 for CEX-bus, TB807 for ModuleBus, and TB852 for RCU-Link) on unused extension ports to prevent bus signal reflection. Connect the primary 24 VDC supply conductors to the baseplate terminal block, keeping supply wiring within the specified 19.2 to 30 VDC operating window. Route Ethernet cables (CN1, CN2) separately from high-voltage AC lines to prevent common-mode noise from corrupting high-speed network traffic.