EC401-50 S3 Yokogawa DCS ESB Bus Coupler Module

• Brand
  Yokogawa
• Model
  EC401-50 S3
• Product Name
  ESB Bus Coupler Module
• Place of Origin
  Japan
• HS Code
  8517.62
• Dimensions
  22 × 124 × 126 mm
• Weight
  0.1–0.3 kg
• Operating Temperature
  0 °C to +55 °C
• Storage Temperature
  −20 °C to +70 °C
• Power Supply
  10 Mbps
• Warranty
  1 year
• Product Status
  new brand

The Yokogawa EC401-50 S3 is a single-port ESB Bus Coupler Module engineered for Yokogawa's Field I/O (FIO) system. Rather than processing field-level analog or digital signals directly, it serves as a high-speed communication interface that bridges the Field Control Unit (FCU) and ESB Bus Node Units within CENTUM VP and CENTUM CS 3000 distributed control architectures. Style S3 or later is required to ensure compatibility with the CP471 processor module.

At its core, the module operates on the ESB (Ethernet Smart Bus) protocol through one front-panel CN1 connector, delivering a transmission speed of 128 Mbps for I/O data exchange. It supports up to nine connectable node units—including the ANB10S, ANB10D, ANT401, ANT411, and ANT421—over a maximum cable distance of 10 meters, with the actual node count varying according to the FCS database configuration. For high-availability deployments, two EC401 modules can be installed in the same FCU to implement a dual-redundant ESB bus architecture with automatic failover.

Power is supplied via the FCU backplane at 24 V DC, with the module drawing 0.5 A and consuming approximately 5 W under nominal operating conditions. Physically, the unit measures 130 mm in height, 129.5 mm in width, and 32.8 mm in depth, weighing 0.24 kg, and is designed for FCU rack or DIN-rail installation with an IP20 protection rating. It operates reliably across a temperature range of 0 to 55 °C, withstands storage temperatures from -40 to 85 °C, and tolerates humidity levels between 5 and 95 % RH without condensation.

Manufactured in Japan, the EC401-50 S3 carries the HS tariff code 8537101190. It is important to note that this module does not provide field-side analog channels (such as 4–20 mA or 0–10 V) or discrete I/O points; those signal-handling functions reside in dedicated I/O modules housed within the ESB Node Units, while the EC401 exclusively manages the deterministic communication backbone between the controller and the field nodes.

Yokogawa EC401-50 S3 ESB Bus Coupler Module — Wiring and Connection Guide

The EC401-50 S3 is a single-port Extended Serial Bus (ESB) coupler module engineered for Yokogawa CENTUM VP and CS 3000 distributed control systems. Rather than serving as a field I/O terminal, it acts as the communication bridge linking the Field Control Unit (FCU) to downstream ESB Bus Node Units.

Slot Placement

In a standalone non-redundant setup, mount the EC401-50 S3 in Slot 7 of the FCU, leaving Slot 8 vacant or fitted with a blank module as required by the FCU variant. For dual-redundant operation, insert two matched EC401-50 S3 modules into Slot 7 and Slot 8 respectively. Note that Style S3 or a later revision is mandatory when pairing this module with a CP471 processor.

ESB Bus Cabling

Connection to ESB Bus Node Units is made through a purpose-built ESB bus cable terminating in a 36-pin locking connector. Only Yokogawa-approved shielded twisted-pair ESB cables with locking connectors should be used to guard against unintended disconnection. The bus carries data at 128 Mbps and permits a maximum run of 10 meters from the FCU to any connected node. One EC401 module supports up to nine node units, encompassing models such as the ANB10S, ANB10D, ANT401, ANT411, and ANT421. A properly rated terminating resistor must be fitted at the physical end of every bus segment to suppress signal reflections.

Power

Power is drawn directly from the FCU backplane; no independent field power wiring is needed for the coupler itself. The module draws approximately 0.5 A at 5 V DC within a 24 V DC system.

Installation and Grounding Practice

Keep ESB communication runs physically separated from high-voltage power cabling inside the enclosure to reduce electromagnetic interference. Ensure consistent, low-resistance grounding throughout the cabinet and employ a clean dedicated earth to minimize noise. Where explosion-protected versions are deployed, all wiring must conform to relevant hazardous-area regulations—including ATEX, IECEx, and NEC Article 501/504—with certified cable glands, seals, and grounding methods in place.

Fiber Optic ESB Extension

For longer-distance extensions implemented through Optical ESB Bus Repeater Modules, use LC-type connectors meeting IEC 61754-20 together with quartz single-mode fiber (JIS C6835 SSMA-9.3/125, IEC 60793-2-50B1.1). Copper segments associated with the EC401 remain limited to 10 meters, while fiber distances are determined by the repeater module's own specifications.

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  Yokogawa EC401-50 S3 datasheet PDF
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