Product Core Brief
- Model: EC401-50
- Brand: YOKOGAWA
- Series: CENTUM CS 3000 R3 FFCS
- Core Function: 1-port ESB bus coupler that links FIO/N-IO node units to the Field Control Unit via the ESB bus.
- Product Type: DCS ESB Bus Coupler Module
- Key Specs: 128 Mbps transmission | Max 10 m bus distance | 0.5 A current draw
- Condition: New Surplus / Tested
Key Technical Specifications
- Module Type: ESB Bus Coupler Module (EC401 series)
- Suffix Code: -50 (Standard type, no explosion protection, 1-port for N-IO/FIO)
- System Compatibility: CENTUM CS 3000 R3 FFCS
- Bus Architecture: ESB (Extended Serial Backboard Bus)
- Bus Ports: 1-port ESB bus port
- Transmission Speed: 128 Mbps (I/O module data transmission)
- Transmission Distance: Max. 10 m
- Connectable Units: Max. 9 node units
- Current Consumption: 0.5 A
- Weight: Approx. 0.24 kg
- Supported FCUs: AFV30S, AFV30D, AFV40S, AFV40D, A2FV50S, A2FV50D, A2FV70S, A2FV70D
- Redundancy: Dual modules can be installed for dual-redundant ESB bus configuration
Product Introduction (No Fluff)
The EC401-50 is a 1-port ESB bus coupler module used in the YOKOGAWA CENTUM CS 3000 R3 FFCS platform. It installs in the Field Control Unit for FIO (AFV30/AFV40/A2FV50/A2FV70 series) and provides the ESB bus interface needed to connect up to 9 FIO/N-IO node units at 128 Mbps over distances up to 10 meters.
For maintenance teams keeping legacy CS 3000 R3 systems online, this module is a direct-fit replacement when expanding I/O capacity or restoring a failed coupler. Dual-redundant c
onfiguration is supported by installing two units in the same FCU, which is standard practice for critical process loops.
QA & Testing SOP (Dynamic & Transparent)
We treat every ESB coupler the same way we’d verify one before slotting it into a live FCU:
- Visual & authenticity check: Inspect housing, label, connector pins, and solder joints for rework, corrosion, or counterfeit indicators.
- Connector & pin inspection: Verify the ESB bus connector alignment and pin integrity—bent or oxidized pins are a common failure mode on older FFCS communication modules.
- Bench power-up test: Apply rated power on an OEM-compatible test rack and confirm module initialization without fault LEDs.
- Bus communication verification: Confirm the module registers on the ESB bus and maintains stable communication with a paired SB401 slave module on a test node unit.
- ESD-safe packaging: After testing, the unit is sealed in anti-static shielding with moisture barrier protection for shipment.
Installation Pitfalls & Guide (Engineer to Engineer)
❗ Do notup with -10 or -E0. The -50 is a 1-port ESB coupler for FIO/N-IO node units; the -10 is a communication module variant for FFCS CPU nodes; the -E0 adds explosion protection. Wrong suffix = wrong application.
❗ Watch the 10-meter cable limit. ESB bus runs on YCB301 cable with a hard 10 m maximum distance. If you need longer runs, you should be looking at ER bus (EB401/EB501) instead.
❗ Redundancy requires matched pairs. If your FCU runs dual EC401-50 modules, verify both modules’ status before returning to service. A mismatched or degraded module can cause bus instability.
❗ Backplane seating is critical. FFCS IOM slots are tight. Force-fitting can bend backplane pins. Seat the module evenly and verify the locking mechanism before powering up.
Replacement steps:
- Pre-install: Confirm slot position, redundancy status, and backplane power state.
- Removal: Power down the FCU if non-redundant; release the module latch and withdraw straight out.
- Install: Align pins carefully, seat fully, and secure the latch.
- Power-on test: Restore power, verify LED status, and confirm ESB bus communication with connected node units.
Technical FAQ
What does the EC401-50 do? It is a 1-port ESB bus coupler that connects FIO/N-IO node units (ANB10*/ANR10* series) to the Field Control Unit in a CENTUM CS 3000 R3 FFCS system, supporting up to 9 nodes at 128 Mbps.
What is the difference between EC401-50 and EC401-E0? The -50 is the standard type without explosion protection. The -E0 variant adds explosion protection certification. Both are 1-port ESB couplers for FIO/N-IO.
Can I use this in a redundant configuration? Yes. Installing two EC401-50 modules in the same FCU creates a dual-redundant ESB bus. This is recommended for critical process applications.
Is this compatible with EC401-10? They are in the same EC401 family but serve different roles. The -10 is used in FFCS CPU nodes, while the -50 is used in Field Control Units for FIO. They are not interchangeable.
What is the warranty? Surplus and tested units typically carry a 12-month functional warranty. Confirm exact terms at checkout, as condition varies by lot.
