Yokogawa ANT Series Modules: ANT421-50 S1 Bus Repeater Master

Technical Dossier

Product Details And Specifications

Yokogawa ANT Series Technical Notes

The Yokogawa ANT Series constitutes the bus repeater and field bus communication backbone of the CENTUM CS 3000 and CENTUM VP distributed control systems — two of the most widely deployed DCS platforms in global heavy industry. Installations span petrochemical complexes, nuclear power generation facilities, LNG terminals, crude oil refineries, and continuous-process chemical plants across Asia-Pacific, the Middle East, and Europe. The ANT Series modules perform signal regeneration, bus extension, and master/slave arbitration on the V-net and ER Bus architectures that interconnect field control stations (FCS), human interface stations (HIS), and engineering workstations (EWS). Their role is infrastructure-critical: a failed bus repeater can isolate an entire field control domain, making reliable spare parts availability a plant-continuity requirement rather than a maintenance preference.

The Evolution of ANT Series Architecture

The ANT Series was introduced alongside the CENTUM CS 3000 platform in the late 1990s as Yokogawa transitioned from the earlier CENTUM XL and CENTUM-V architectures. Early ANT modules operated exclusively on the V-net coaxial bus at 10 Mbps, providing deterministic token-passing communication between FCS nodes. With the release of CENTUM VP (circa 2008), Yokogawa introduced dual-redundant Ethernet-based control bus (Vnet/IP) while retaining backward compatibility with legacy V-net ANT hardware — a deliberate design decision that extended the operational life of existing ANT infrastructure by over a decade.

ANT Series Full Catalog & Functionalities (SKU List)

The following SKUs represent the core ANT Series module range across bus repeater master, slave, and auxiliary functions. All models are classified by their role in the V-net / ER Bus topology:

Bus Repeater Master Modules

• ANT421-50 S1: V-net bus repeater master, 50-ohm coaxial, single-port, CS 3000 / VP compatible
• ANT421-10 S1: V-net bus repeater master, 10-ohm variant, for short-segment installations
• ANT421-50 S2: Revised firmware bus repeater master, 50-ohm, enhanced diagnostics
• ANT421-10 S2: Revised firmware bus repeater master, 10-ohm, enhanced diagnostics

Bus Repeater Slave Modules

• ANT431-50 S1: V-net bus repeater slave, 50-ohm, paired with ANT421 master in extended bus segments
• ANT431-10 S1: V-net bus repeater slave, 10-ohm, short-segment slave node
• ANT431-50 S2: Slave module, 50-ohm, revised hardware for VP-generation cabinets

ER Bus / Field Bus Communication Modules

• ANT100-S10: ER Bus interface module, single-channel, FCS-side termination
• ANT100-S20: ER Bus interface module, dual-channel, redundant field bus path
• ANT200-S10: Extended ER Bus repeater, single-channel, for long-distance field runs
• ANT200-S20: Extended ER Bus repeater, dual-channel, redundant topology support

Bus Termination & Auxiliary Modules

• ANT510-50: V-net coaxial bus terminator, 50-ohm, end-of-segment passive termination
• ANT510-10: V-net coaxial bus terminator, 10-ohm, short-segment passive termination
• ANT600: Bus diagnostic and monitoring module, inline signal quality measurement
• ANT700-S1: Optical bus converter module, coaxial-to-fiber interface for long-distance or electrically noisy environments
• ANT800-S1: Redundant bus switch module, automatic failover between primary and secondary V-net segments

Quality Control for the ANT Series Range

ANT Series modules present specific test challenges due to their role as active bus arbitration devices. Standard power-on verification is insufficient; functional validation requires live V-net bus simulation to confirm token-passing arbitration, signal regeneration amplitude, and timing compliance. DriveKNMS applies the following test protocol to all ANT Series units:

• Visual inspection: PCB condition, connector pin integrity, conformal coating assessment
• Power rail verification: +5 V, +12 V, and −12 V rail tolerance check under load
• V-net bus simulation: Token-passing cycle verification using calibrated bus test equipment
• Signal amplitude measurement: Coaxial output signal level within Yokogawa-specified tolerance bands
• Firmware revision confirmation: Label and internal register cross-check against declared suffix
• Burn-in cycle: 48-hour powered operation prior to shipment for early-failure screening