Description

Yokogawa EC402-51 ESB Bus Coupler Module

The Yokogawa EC402-51, also cataloged as the EC402 ESB Bus Coupler Module, operates as a dedicated hardware component for high-speed ESB bus master interfacing within CENTUM VP and CS 3000 distributed control systems.

Suffix Breakdown & Model Matrix

• EC402: ESB Bus Coupler Module for N-IO / FIO, 2-Port type
• -5: Standard type with no explosion protection
• 1: ISA Standard G3 conformal coating for corrosion and chemical resistance

Hardware Specifications

Parameter	Specification
ModelBrand	Yokogawa EC402-51
Origin	Japan
Weight	Approx. 0.24 kg
Dimensions	32.8 mm × 130.0 mm × 129.5 mm
OperatingTemp	-10 degC to +60 degC
PowerConsumption	0.5 A
Function	ESB Bus Master Interface
Compatible Systems	CENTUM VP / CS 3000 (AFV30, AFV40, A2FV50, A2FV70 FCUs)
TransmissionSpeed	128 Mbps
ConnectableUnits	Upper: Max. 9, Lower: Max. 9, Total Max: 13
TransmissionDistance	Upper: Max. 10 m, Lower: Max. 10 m, Total Max: 20 m
DataBufferSize	128 KB

DCS Bus Communication and Channel Isolation

The EC402-51 implements deterministic ESB bus communication with isolated upper and lower ports, minimizing cross-channel interference. Dual-redundant deployment is supported by pairing two modules in adjacent FCU slots to maintain continuous I/O data flow during maintenance or module failure. The module’s data buffering ensures low-latency response times (~10 ms) for remote ESB node interactions.

Frequently Asked Questions

Q: Can the EC402-51 be hot-swapped while the FCU is online?
A: No. Replacement requires controlled FCU shutdown or redundant module support to avoid data loss.

Q: What is the maximum number of ESB nodes supported per EC402-51 module?
A: Up to 9 nodes on the upper port and 9 nodes on the lower port, with a system total of 13 nodes.

Q: How is the module protected against harsh environmental conditions?
A: The EC402-51 with suffix “-1” includes ISA Standard G3 conformal coating, providing resistance to corrosive chemical environments.

Field Installation Guidelines

• Mount module directly into designated FCU slot with proper slot alignment
• Maintain grounding continuity to FCU backplane and chassis earth
• Use standard Yokogawa YCB301 ESB bus cables, observing maximum distances of 10 m per port
• Keep bus cabling physically separated from high-voltage lines to prevent EMI
• Verify dual-redundant modules are installed in correct slot pairs for continuous bus availability
• Ensure airflow clearance around adjacent modules to prevent thermal accumulation

Specifications

• Brand: Yokogawa

Advantages

• High reliability in industrial environments
• Supports continuous operation
• Compatible with major PLC/DCS systems