Product Core Brief
- Model: EC401-50
- Brand: YOKOGAWA
- Series: CENTUM CS 3000 / Field Control Unit (FCU)
- Core Function: ESB bus coupler that links the processor module to remote I/O nodes in a CENTUM CS 3000 field control station.
- Product Type: ESB Bus Coupler Module
- Key Specs: 1-port ESB bus coupler | Standard type without explosion protection | Supports redundant pair configuration
- Condition: New Surplus / OEM Original
Key Technical Specifications
- Part Number:
- Product Type: ESB Bus Coupler Module for CENTUM CS 3000 FCU
- System Compatibility: CENTUM CS 3000 Field Control Unit
- Bus Interface: ESB bus
- Port Configuration: Single-port ESB bus coupler
- Suffix Meaning: “-5” = standard type without explosion protection; “0” = basic version
- Redundancy: Dual-redundant configuration supported by installing two EC401-50 modules
- Typical FCU Partners: AFV-series FCU with compatible processor such as CP471-01
- EC401 Style Requirement: CP471-01 requires EC401 style S3 or later
- Mounting: FCU backplane slot
- Explosion Protection: None (standard industrial type)
Product Introduction
The EC401-50 is an ESB bus coupler module for YOKOGAWA CENTUM CS 3000 field control units. It sits between the FCU processor and the ESB bus, enabling communication with remote I/O nodes and keeping control execution and field data exchange properly synchronized.
Its main value shows up during maintenance and expansion. A redundant pair can maintain bus communication if one coupler fails, and the standard non-explosion-proof version fits most indoor DCS cabinets. Always verify the EC401 style code before pairing it with newer processors.
QA & Testing SOP
- Label and counterfeit check: Verify “EC401-50” marking, suffix code, PCB revision, and connector condition.
- Backplane connector inspection: Check for bent pins, corrosion, or contamination before insertion.
- Cold-boot test: Install into a verified FCU rack, apply power, and confirm module initialization and status LEDs.
- ESB communication check: Confirm the coupler is recognized by the processor and that remote I/O nodes are reachable.
- Redundancy verification: If two EC401-50 modules are installed, confirm primary/standby status and failover behavior.
All units are handled with ESD-safe packaging and labeled with received condition, inspection date, and test status.
Installation Pitfalls & Guide
- ❗ Check the EC401 style code. CP471-01 requires EC401 style S3 or later; older styles may not be compatible.
- ❗ Do not mix different EC401 styles in a redundant pair. Redundant couplers should be matched for predictable failover.
- ❗ Protect the backplane connector. Bent pins or dirty contacts are a common cause of communication faults after replacement.
- ❗ Confirm ESB cable routing and termination. Loose or misrouted ESB cables can cause intermittent node dropouts.
Replacement steps:
- Verify FCU type, processor compatibility, and EC401 style code.
- Remove the failed coupler following ESD procedures.
- Seat the new EC401-50 firmly and verify connector alignment.
- Power on, confirm ESB communication, and test redundancy if applicable.
Technical FAQ
What does EC401-50 do in a CENTUM CS 3000 system?
It acts as the ESB bus coupler inside the field control unit, linking the processor to remote I/O nodes over the ESB bus.
Can I run it in a redundant configuration?
Yes. Two EC401-50 modules can be installed as a redundant pair to maintain ESB bus communication if one fails.
Is compatible with CP471-01?
It can be, but only if the EC401 is style S3 or later. Always check the style code before installation.
What does the “-50” suffix mean?
“-5” indicates a standard type without explosion protection, and “0” indicates the basic version.
Do you test these before shipping?
Surplus stock is visually inspected, connector-checked, and power/communication-tested where a suitable CENTUM CS 3000 test rack is available. Any limitations are disclosed per lot.
