Hitachi LUD Series Modules

Technical Dossier

Product Details And Specifications

Hitachi LUD Series: Comprehensive Module Range and Technical Overview

The Hitachi LUD Series represents a core product line within Hitachi's industrial distributed control system (DCS) and programmable logic controller (PLC) infrastructure. These modules have been deployed extensively across global heavy industries including petrochemical refineries, nuclear power generation facilities, chemical processing plants, and steel manufacturing operations. The LUD Series occupies a critical position in Hitachi's control architecture, providing CPU processing, digital/analog I/O interfacing, and inter-module communication functions within rack-based control cabinets. Installed base across Asia-Pacific, the Middle East, and Europe remains substantial, making long-term spare parts availability a primary operational concern for plant maintenance engineers.

The Evolution of LUD Series Architecture

The Hitachi LUD Series was developed as part of Hitachi's HIDIC (Hitachi Distributed and Integrated Control) platform, which emerged in the late 1980s and matured through the 1990s and 2000s. Early LUD modules operated on a proprietary parallel backplane bus with fixed slot addressing, limiting hot-swap capability. Mid-generation revisions introduced improved ASIC-based I/O scanning and expanded memory addressing, enabling larger ladder logic programs and faster scan cycles. Later variants incorporated enhanced EMI shielding and extended operating temperature ranges to meet IEC 61131-2 environmental classifications for industrial enclosures.

Compatibility across LUD sub-generations is constrained by backplane bus revision. Modules from the LUD0xx sub-family are generally interchangeable within the same rack generation, while LUD1xx and LUD2xx variants may require firmware alignment or rack backplane hardware revision before substitution. Engineers performing module replacement must verify the rack base unit revision code stamped on the backplane PCB before ordering a substitute module. The series has entered the mature/end-of-life phase; Hitachi has formally discontinued active production of most LUD variants, transitioning customers toward the HIDIC H Series and EH-150 platform. This makes third-party lifecycle support and certified refurbished inventory the primary sourcing channel for ongoing plant maintenance.

LUD Series Full Catalog & Functionalities (SKU List)

The following SKUs represent verified, commonly documented modules within the Hitachi LUD Series. Modules are classified by primary function:

CPU / Controller Modules

• LUD070A: Main CPU controller module, rack-mount, HIDIC bus interface, ladder logic execution
• LUD071A: Enhanced CPU module with expanded program memory and faster scan cycle
• LUD072A: Redundant CPU controller module for high-availability control configurations
• LUD073A: CPU module with integrated serial communication port (RS-232C)
• LUD074A: CPU module variant with extended temperature rating for harsh environments

Digital Input (DI) Modules

• LUD110A: 16-point 24VDC digital input module, sink/source configurable
• LUD111A: 32-point 24VDC digital input module, high-density rack format
• LUD112A: 16-point 100-120VAC digital input module, optically isolated
• LUD113A: 16-point dry contact digital input module, for field switch interfaces

Digital Output (DO) Modules

• LUD120A: 16-point 24VDC transistor output module, 0.5A per point
• LUD121A: 16-point relay output module, 2A per point, Form-C contacts
• LUD122A: 32-point 24VDC transistor output module, high-density

Analog I/O Modules

• LUD210A: 4-channel analog input module, 4–20mA / 0–10V selectable, 12-bit resolution
• LUD211A: 8-channel analog input module, 4–20mA, 12-bit resolution
• LUD220A: 4-channel analog output module, 4–20mA, 12-bit DAC

Communication / Adapter Modules

• LUD310A: HIDIC network communication adapter, peer-to-peer inter-rack data exchange
• LUD311A: RS-485 Modbus RTU communication module for third-party device integration
• LUD312A: Ethernet TCP/IP communication module, 10BASE-T, SCADA interface

Power Supply Modules

• LUD410A: 24VDC rack power supply module, 5A output, input 100–240VAC
• LUD411A: Redundant power supply module, hot-swap capable, for critical applications

Sourcing Hard-to-Find & Obsolete LUD Series Parts

With Hitachi having formally discontinued the LUD Series production line, the global supply of new-old-stock (NOS) and certified refurbished modules is finite and diminishing. DriveKNMS maintains a dedicated inventory program for Hitachi LUD Series lifecycle support, sourcing modules through verified industrial surplus channels, decommissioned plant equipment, and authorized refurbishment partners.

For plant operators who cannot migrate to a modern control platform due to capital expenditure constraints, integration complexity, or regulatory approval timelines, DriveKNMS provides a structured lifecycle extension service: module identification and cross-referencing, functional testing against original Hitachi specifications, documented test reports, and warranty-backed dispatch. Customers operating refineries, power stations, or continuous-process chemical plants with embedded LUD Series infrastructure are the primary beneficiaries of this service. Minimum order quantities are flexible; single-unit emergency replacement orders are accepted. Lead times for common variants such as the LUD070A, LUD110A, and LUD210A are typically 3–7 business days from confirmed stock.

Quality Control for the LUD Series Range

The Hitachi LUD Series employs a proprietary backplane bus protocol and ASIC-based I/O scanning architecture that requires specialized test procedures beyond standard continuity and power-on checks. DriveKNMS applies the following test protocol to all LUD Series modules prior to dispatch:

• Backplane Bus Communication Test: Each module is seated in a reference LUD rack and subjected to full HIDIC bus enumeration to confirm correct slot addressing and data frame integrity.
• CPU Execution Verification: For CPU modules (LUD070A and variants), a standardized ladder logic test program is loaded and executed across 1,000 scan cycles. Scan time consistency and output response accuracy are logged.
• I/O Point-Level Functional Test: All digital and analog I/O points are individually stimulated and measured. Analog modules are calibrated against a traceable reference standard; deviation exceeding ±0.5% of full scale triggers rejection.
• Thermal Stress Screening: Modules are operated at elevated ambient temperature (55°C) for a minimum of 4 hours to screen for latent component failures.
• Visual and Component Inspection: PCB inspection under magnification for capacitor condition, solder joint integrity, and corrosion on edge connectors. Connector pins are cleaned and re-tensioned where applicable.

All test results are documented and available upon request with each shipment.