ABB CI856K01 (3BSE026055R1) – Communication Interface for AC 800M to Legacy S100 I/O

The ABB CI856K01 is a communication interface module for System 800xA/AC 800M that enables continued use of installed ABB S100 I/O. From my experience, plants use it to modernize control processors while keeping proven field wiring and I/O marshalling in place. This typically cuts downtime and migration cost, especially in brownfield projects where every hour of shutdown matters.

• Seamless AC 800M integration – Designed to work within the 800xA architecture so engineering, diagnostics, and asset management stay centralized.

• S100 I/O connectivity – Bridges AC 800M controllers to existing ABB S100 I/O racks, allowing staged system migrations.

• Redundancy support – In many cases, CI856 modules can be deployed in redundant pairs to enhance availability on critical loops.

• Hot?swap serviceability – You might notice that maintenance is simpler; module replacement is typically done without rewiring thanks to the dedicated terminal base.

• Lifecycle-friendly engineering – Keeps your existing marshalling and cabinets, minimizing requalification efforts and plant re?documentation.

• System diagnostics – Clear status indications and 800xA alarms make troubleshooting faster for operations teams.

The CI856K01 is typically used where legacy S100 I/O remains reliable, but the control platform needs a refresh. Common sectors include:

• Pulp & paper – phased migration during shutdown windows without re?terminating hundreds of I/O pairs.

• Chemicals & specialty materials – keep certified field devices and hazardous?area wiring, upgrade the controller and HMI layer.

• Metals & mining – extend installed I/O life while adding modern diagnostics through 800xA.

• Power & utilities – improve maintainability and spares strategy without changing protection circuits.

• Protects existing I/O investment – No wholesale rewiring, fewer new cabinets, and less test/validation work.

• Shorter outages – One thing I appreciate is how migration can be staged controller?first, then I/O later, as budgets allow.

• Compatibility and service – Works within the 800xA toolset so engineering teams don’t juggle mixed environments.

• Lower total cost – In many cases, reuse of S100 I/O trims labor hours, scaffolding, and commissioning time.

A maintenance manager at a paper mill told us the “CI856 path let us upgrade to AC 800M with a two?shift outage; all field terminations stayed, which saved the turnaround.”

• Panel environment – Install on DIN rail inside a clean, ventilated cabinet (IEC/UL industrial panel). Keep ambient within 0–55?°C and humidity within spec.

• Terminal base – Mount the module on the correct ABB terminal base (commonly TB856 series). Ensure the base is properly grounded to the cabinet PE.

• Wiring – Use shielded cable for the S100 I/O link, observe ABB guidelines for cable length and termination. Route signal and power separately to reduce noise.

• Redundancy – Where high availability is required, deploy redundant CI856 pairs and segregate power feeds. Verify switchover behavior during FAT/SAT.

• Safety – De?energize field loops when practical; follow ESD handling for module swaps. Confirm firmware/800xA version compatibility before upgrading.

• Routine care – Periodically check connector torque, clean dust with dry air, back up configuration, and keep firmware aligned with your 800xA baseline.

• CE marked; designed for industrial EMC compliance.

• UL/cUL recognition for control equipment (model dependent, typically applicable to AC 800M modules).

• RoHS compliant materials.

• Manufactured under ISO 9001 quality systems.

• Manufacturer’s warranty: ABB limited warranty, typically 12 months from shipment (terms may vary by region and contract).

• PM8xx Series AC 800M Controllers (e.g., PM861/PM864) – controller CPUs for 800xA.

• TB856 Terminal Base – mounting and backplane connection for CI856 modules.

• ABB S100 I/O Racks and Modules – existing field I/O preserved during migration.

Note: Specifications can vary slightly by firmware revision and system configuration. If you’re planning a phased migration, share your 800xA version and S100 I/O details and we can validate compatibility before order.