Fuji Electric EP-3955B High Power Motherboard

Technical Dossier

Product Details And Specifications

FUJI TEC-1VM Series Technical Notes

The Evolution of TEC-1VM Architecture

The TEC-1VM platform was introduced as part of Fuji Electric's mid-generation DCS and programmable controller expansion during the late 1990s and early 2000s. Early revisions of the architecture utilized parallel backplane bus communication with fixed-slot addressing, which imposed strict module positioning requirements within the rack. Subsequent hardware revisions introduced improved bus arbitration logic and enhanced EMI shielding to address interference issues observed in high-voltage industrial environments.

The EP-3955B High Power Motherboard specifically addresses power delivery requirements for racks populated with high-current I/O modules and communication adapters. Compatibility across TEC-1VM sub-revisions requires verification of firmware version alignment between the motherboard and installed CPU modules. Older EP-series motherboards are not forward-compatible with later-generation CPU cards without hardware modification. As the TEC-1VM series has entered its mature-to-end-of-life phase, Fuji Electric has transitioned support to successor platforms; however, the installed base remains extensive, making long-term spare parts availability a critical operational concern for maintenance engineers.

TEC-1VM Full Catalog & Functionalities (SKU List)

The following SKUs represent verified components within the FUJI TEC-1VM series, organized by functional category. Each module is a discrete field-replaceable unit (FRU) within the TEC-1VM rack architecture.

Motherboards & Backplanes

• EP-3955B: High power motherboard; primary backplane for multi-slot TEC-1VM rack configurations with enhanced power bus capacity.
• EP-3954A: Standard power motherboard; base backplane for standard I/O density rack builds.
• EP-3956C: Extended slot backplane; supports up to 16-module configurations for high-density I/O applications.

CPU & Controller Modules

• TEC-1VM-CPU01: Main processing unit; executes ladder logic and function block programs with deterministic scan cycle control.
• TEC-1VM-CPU02: Redundant CPU module; hot-standby configuration for fault-tolerant control applications.
• TEC-1VM-CPU03: High-speed CPU variant; reduced scan cycle time for fast-response process control loops.

Digital Input (DI) Modules

• TEC-1VM-DI16A: 16-channel 24VDC digital input module; sink/source configurable, with per-channel LED status indication.
• TEC-1VM-DI32B: 32-channel high-density digital input module; compact form factor for space-constrained panel installations.
• TEC-1VM-DI16C: 16-channel 120VAC digital input module; for direct interface with AC field devices without external signal conditioning.

Digital Output (DO) Modules

• TEC-1VM-DO16A: 16-channel transistor output module; 24VDC, 0.5A per channel, short-circuit protected.
• TEC-1VM-DO16B: 16-channel relay output module; dry contact, rated 2A per channel for motor starter and solenoid valve control.
• TEC-1VM-DO32A: 32-channel high-density transistor output; for large-scale discrete output applications.

Analog Input (AI) Modules

• TEC-1VM-AI08A: 8-channel analog input module; 4–20mA / 0–10V selectable, 12-bit resolution, for process variable acquisition.
• TEC-1VM-AI08B: 8-channel thermocouple input module; supports J, K, T, E type thermocouples with cold junction compensation.

Analog Output (AO) Modules

• TEC-1VM-AO04A: 4-channel analog output module; 4–20mA, 12-bit resolution, for control valve and variable speed drive setpoint transmission.

Communication Adapters

• TEC-1VM-COM01: RS-232C/RS-485 serial communication adapter; for SCADA host and HMI connectivity via Modbus RTU protocol.
• TEC-1VM-COM02: Ethernet communication module; 10/100 Mbps, supports Modbus TCP and proprietary Fuji protocol for DCS integration.
• TEC-1VM-COM03: PROFIBUS-DP slave adapter; for integration into Siemens and third-party PROFIBUS master networks.

Power Supply Modules

• TEC-1VM-PSU01: 24VDC rack power supply; 10A output, wide-range AC input (85–264VAC), with power-fail relay output.
• TEC-1VM-PSU02: Redundant power supply module; for N+1 power redundancy configurations in critical process applications.

Quality Control for the TEC-1VM Range

The TEC-1VM series employs a proprietary parallel backplane bus architecture with tight electrical timing tolerances. Standard bench testing procedures are insufficient to validate module integrity for this platform. DriveKNMS applies a dedicated test protocol for TEC-1VM components that includes the following stages:

• Backplane Bus Integrity Test: The EP-3955B and other backplane modules are tested under simulated full-rack load conditions to verify bus signal integrity, power rail stability, and slot-to-slot communication timing compliance.
• CPU Functional Verification: CPU modules are loaded with a standardized test program and executed through a full scan cycle sequence to confirm program execution, memory integrity, and communication port functionality.
• I/O Channel-Level Testing: Each channel of DI, DO, AI, and AO modules is individually stimulated and measured against factory specification tolerances. Analog modules are calibrated using traceable reference instruments.
• Communication Protocol Validation: Communication adapter modules are tested for protocol compliance using protocol analyzers configured for Modbus RTU, Modbus TCP, and PROFIBUS-DP as applicable.
• Thermal Burn-In: Selected modules undergo a 48-hour powered burn-in at elevated ambient temperature to screen for latent component failures prior to shipment.
• Visual and Physical Inspection: All modules are inspected for connector pin condition, PCB contamination, capacitor condition, and evidence of prior repair or counterfeit indicators.