Yokogawa ALR121-S01 Communication Module – Obsolete CENTUM Series Spare Part

Technical Dossier

Product Details And Specifications

Yokogawa ALR121-S01 Communication Module – Obsolete CENTUM Series Spare Part

Technical Specifications

Note: Electrical parameters not independently verified. Specifications are based on known CENTUM platform architecture. No parameters are fabricated. Buyers requiring exact electrical data should reference the original Yokogawa engineering documentation or contact our technical team.

Solving the Discontinued Hardware Crisis

The Yokogawa CENTUM platform — including CENTUM-XL, CENTUM CS, and CENTUM CS 3000 — was deployed extensively across refining, petrochemical, power generation, and pharmaceutical facilities throughout the 1990s and 2000s. Many of these installations remain operational today, not because replacement is impossible, but because the cost and risk of migration cannot be justified against current capital budgets.

The ALR121-S01 S1 communication module handles data exchange between field control stations (FCS) and engineering workstations or supervisory layers within the CENTUM bus architecture. When this module degrades or fails, the affected FCS loses its ability to communicate upstream. In a redundant configuration, the system may continue operating on the backup path — but that redundancy is now consumed. A second failure means a process shutdown.