Description
| Product model | ARND-3119 A6 (marketing/model number) / 2N3A3119-B (PCB assembly number) |
| Manufacturer | Toshiba Corporation (Industrial Systems Division) |
| Product category | Digital Input/Output (DI/DO) Interface Module |
| Platform | TOSMAP™ Distributed Control System (DCS) – commonly used in Japanese power plants |
| I/O configuration | Typically 16 channels (configurable as input or output via jumpers or firmware) |
| Input type | 24V DC sourcing/sinking (compatible with dry contacts and solid-state sensors) |
| Output type | Relay or transistor outputs (depends on exact revision; often relay for alarms) |
| Isolation | Opto-isolation per channel or group; ≥500V between field and logic |
| Communication | Proprietary TOSMAP backplane bus; integrates into system I/O image |
| Mounting | Slide-in module for standard TOSMAP I/O chassis |
| Operating temperature | 0°C to +55°C (industrial environment) |
| Diagnostic features | LED indicators per channel; fault reporting via TOSMAP operator station |
Product Introduction
The Toshiba ARND-3119 A6 (2N3A3119-B) is a digital interface module developed for the TOSMAP (Toshiba Supervisory and Monitoring Automatic Processor) distributed control system—a legacy DCS platform widely deployed in Japanese-built fossil fuel, nuclear, and combined-cycle power plants from the 1980s through early 2000s. This module serves as a critical bridge between the TOSMAP controller and field devices, handling discrete signals such as motor run status, valve position feedback, trip interlocks, and alarm annunciation relays.
As part of Toshiba’s industrial automation heritage, the ARND-3119 A6 was engineered for high reliability in electrically noisy power generation environments. Its robust opto-isolation and conformal-coated PCB protect against voltage transients, humidity, and dust—common challenges in turbine halls and boiler rooms. While newer plants have migrated to modern platforms like Ovation or DeltaV, hundreds of TOSMAP systems remain operational globally, making the 2N3A3119-B a vital spare for sustaining plant availability and avoiding forced derates during component failure.
Core Advantages and Technical Highlights
Dual-role flexibility: Depending on configuration, the Toshiba ARND-3119 A6 can function as a digital input module (monitoring switch states) or a digital output module (driving relays or solenoids). This adaptability reduces inventory complexity in plants with mixed I/O needs. Configuration is typically set via internal jumpers or DIP switches, allowing field technicians to repurpose modules during retrofits.
Legacy compatibility with proven ruggedness: Designed before the era of commercial off-the-shelf (COTS) components, the 2N3A3119-B uses industrial-grade discrete electronics and thick-film PCB construction. It lacks microprocessors, relying instead on hardwired logic—making it highly resistant to EMI and software-induced faults. This simplicity contributes to its decades-long service life in harsh conditions.
Seamless integration in TOSMAP architecture: The module communicates directly with the TOSMAP master controller via a parallel backplane bus, requiring no external protocol converters. All I/O points appear in the central database, enabling operators to view and force signals from the console. Its mechanical and electrical design matches other ARND-series modules, ensuring consistent rack loading and thermal performance.
Typical Application Scenarios
The Toshiba ARND-3119 A6 is commonly found in balance-of-plant (BOP) systems within coal, oil, or gas-fired power stations. For example, it may monitor the open/closed status of feedwater isolation valves, detect lube oil pump running conditions, or provide dry contacts to trigger fire suppression systems. In turbine protection circuits, it often interfaces with auxiliary relays that must act independently of software—leveraging its fail-safe hardware design.
During maintenance outages, a failed 2N3A3119-B can cause loss of critical alarms or inability to start auxiliary equipment. Because TOSMAP systems are no longer in production, original spares are scarce. Plants managing aging infrastructure rely on tested refurbished units to maintain operational continuity. The module’s role may seem basic, but its failure can cascade into larger control gaps—especially in safety-related sequences where redundancy is limited.
Related Model Recommendations
Related Model Recommendations- ARND-3120 / 2N3A3120-B: Analog input module for 4–20mA or thermocouple signals—complements digital I/O
- ARND-3121 / 2N3A3121-B: High-speed pulse counter or frequency input module
- ARND-3118 / 2N3A3118-B: Earlier or alternate digital I/O variant—verify pinout compatibility
- TOSMAP CPU Module (e.g., ARNC-1000 series): Central controller that communicates with ARND-3119 A6
- TOSMAP I/O Chassis (e.g., ARNB-5000 frame): Physical rack that houses the 2N3A3119-B module
- ARND-3125: Relay output module with higher contact ratings—for heavy-load switching
- Toshiba TOSMAP Operator Console: Displays status of all I/O points managed by modules like ARND-3119 A6
- 2N3A3119-A / -C: Alternate revisions—check silkscreen and firmware compatibility before substitution
Installation, Commissioning and Maintenance Instructions
Installation preparation: Before installing the Toshiba ARND-3119 A6, de-energize the TOSMAP I/O chassis and follow lockout/tagout procedures. Confirm the module’s jumper settings match the intended I/O function (input vs. output) and voltage level. Align the edge connector carefully with the backplane slot and press firmly until fully seated. Reconnect field wiring using the original terminal mapping—miswiring can damage both the module and field devices.
Maintenance suggestions: Inspect the 2N3A3119-B annually for signs of capacitor leakage, cracked solder joints, or corrosion—especially near high-current traces. Clean dust accumulation with dry, low-pressure air. If multiple channels fail simultaneously, suspect power supply issues rather than module fault. Always keep a spare unit in climate-controlled storage. Due to obsolescence, avoid unnecessary hot-swapping; plan replacements during scheduled outages.
