EB402-50

The Yokogawa EC402-50 is a two-port ESB Bus Coupler Module that provides the master interface between a Field Control Unit (FCU) and ESB Bus Node Units in a CENTUM VP FIO system. It supports I/O data transmission at 128 Mbps, with a maximum of 13 connectable nodes and a total transmission distance of 20 m across its upper and lower ESB bus connections.

Function and Communication Architecture

The EC402-50 performs the ESB bus master interface function, connecting the FCU to distributed Node Units through the ESB communication bus. Its two front-mounted connector ports provide separate upper-side and lower-side bus connections.

Compared with the EC401, the EC402 supports a larger number of connected nodes and a longer transmission distance. This two-port arrangement allows the FCU to communicate with Node Units on both sides of the coupler.

Node Capacity and Transmission Limits

The module supports the following connection limits:

• Upper ESB bus: Maximum 9 units.
• Lower ESB bus: Maximum 9 units.
• Combined capacity: Maximum 13 units.
• Maximum transmission distance: 10 m per bus connection.
• Maximum combined transmission distance: 20 m.

The actual number of connectable nodes depends on the FCS database configuration. The individual upper and lower limits should not be interpreted as permission to connect 18 units simultaneously.

Redundant Bus Configuration

The EC402-50 supports single and dual-redundant ESB bus arrangements when installed in the specified FCU configuration.

For a non-redundant arrangement, install one module in slot 7 and cover slot 8 with a dummy module. For a dual-redundant arrangement, install two ESB Bus Coupler Modules in slots 7 and 8.

This configuration provides redundant communication paths between the FCU and connected Node Units.

Technical Specifications

Parameter	Specification
Model	EC402-50
Brand	Yokogawa
Product Type	ESB Bus Coupler Module
Interface Function	ESB bus master interface
Number of Ports	2
Upper-Side Node Capacity	Maximum 9 units
Lower-Side Node Capacity	Maximum 9 units
Total Node Capacity	Maximum 13 units
Transmission Speed	128 Mbps (I/O module data transmission)
Upper-Side Transmission Distance	Maximum 10 m
Lower-Side Transmission Distance	Maximum 10 m
Total Transmission Distance	Maximum 20 m
Current Consumption	0.5 A
Weight	0.24 kg
Dimensions	32.8 x 129.5 x 130 mm

Compatible Field Control Units

The EC402 is specified for installation in the following Field Control Units for FIO:

• AFV30S / AFV30D
• AFV40S / AFV40D
• A2FV50S / A2FV50D
• A2FV70S / A2FV70D

The FCU slot arrangement must follow the selected ESB bus configuration. For dual redundancy, both slots 7 and 8 are used.

Frequently Asked Questions

Q: What is the maximum number of Node Units supported by the EC402-50?

A: The module supports up to 9 units on the upper bus and 9 units on the lower bus, with a combined maximum of 13 units. The actual capacity depends on the FCS database configuration.

Q: Can the EC402-50 be used in a dual-redundant ESB bus configuration?

A: Yes. Two ESB Bus Coupler Modules are installed in FCU slots 7 and 8 to configure dual-redundant ESB bus communication.

Q: What is the difference between the EC401 and EC402?

A: The EC402 has two ESB bus connector ports and supports a larger number of connected nodes and a longer transmission distance than the EC401. Its maximum combined node capacity is 13 units.

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