Description
Key Technical Parameters
| Parameter | Specification |
|---|---|
| Manufacturer | General Electric (GE) |
| Series | Mark V (Speedtronic) |
| Full Model | DS3800NMFC |
| Power Supply | +5V DC @ 4.0A, +15V DC @ 0.7A, -15V DC @ 0.5A |
| Temperature Inputs | 4 thermocouple channels (12-bit ADC, ±2°C accuracy) |
| Relay Outputs | 8 mechanical relays, 5A continuous @ 115VAC/30VDC (surge 10A) |
| SS Outputs | 4 solid-state relays, 2A continuous @ 24–48VDC |
| Tachometer Inputs | 2 channels (up to 10 kHz) |
| Communication | Mark V proprietary parallel backplane bus |
| Operating Temperature | 0°C to +60°C |
| LED Indicators | Power, Relay Run (8x amber), SS Run (4x green), Tach Fail (red x2), Over-Temp Alarm, Backplane Active |
Advantages and Distinctive Features
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Hybrid Output + Tachometer Feedback: Combines 8 mechanical relays (5A), 4 solid-state outputs (2A), AND 2 tachometer inputs on a single board.
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Fan-Dense Design: 8 relay outputs + 4 SS outputs with only 4 temperature inputs—optimized for single-zone cooling.
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Higher Relay Current (5A): Supports larger AC/DC fans compared to 3A hybrid boards.
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AC/DC Relay Capability: Switches both AC (115VAC) and DC (30VDC) loads.
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Solid-State Auxiliary Outputs: Silent, maintenance-free switching for low-voltage fans or alarms.
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Fan Speed Verification: Tachometer inputs allow CPU to confirm fan operation.
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Complete Galvanic Isolation: 2500V isolation on relay outputs.
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CPU-Dependent Operation: No onboard logic—simple and cost-effective.
Typical Application Fields
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Safety-Critical Fan-Dense Mixed Fan Systems: Where fan failure detection is mandatory.
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Fan-Dense Mixed Fan Cabinets: Where both high-power AC/DC fans and DC auxiliary fans are present with only 4 sensors.
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Climate-Controlled Indoor Installations: 0°C to +60°C range.
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Retrofit Applications: Replacing separate relay, solid-state, and tachometer boards.
Comparison with Related Models
| Feature | DS3800NMFC | DS3800NMFA | DS3800NLCA | DS3800NMEC |
|---|---|---|---|---|
| Relay Outputs | 8 × 5A | 8 × 3A | 8 × 3A | 8 × 5A |
| SS Outputs | 4 × 2A | 4 × 2A | None | 4 × 2A |
| T/C Inputs | 4 | 8 | 4 | 4 |
| Tach Inputs | 2 channels | 2 channels | 2 channels | None |
| ADC | 12-bit (±2°C) | 12-bit (±2°C) | 12-bit (±2°C) | 12-bit (±2°C) |
| Operating Temp | 0°C to +60°C | 0°C to +60°C | 0°C to +60°C | 0°C to +60°C |
| Cost | Medium | Medium | Medium | Medium |
Selection Recommendations
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Choose the DS3800NMFC if:
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You need 5A relay outputs (AC or DC) for main fans.
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You also need solid-state outputs (24–48VDC) for auxiliary fans or alarms.
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You require tachometer feedback for fan speed verification.
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Your cabinet uses 4 temperature sensors for 8 relay outputs + 4 SS outputs (fan-dense configuration).
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You have a climate-controlled environment (0°C to +60°C).
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Choose the DS3800NMFA if: You need 8 thermocouple inputs with tachometer feedback.
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Choose the DS3800NLCA if: You need relay outputs with tachometer feedback without solid-state auxiliaries.
Critical Precautions
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ESD Protection: Always wear a grounded wrist strap.
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High-Voltage/Current Hazard: Relay outputs switch 115VAC/5A—lethal. Use proper insulation.
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Relay Inductive Derating: For inductive fan motors, derate from 5A to 3.5A or use RC snubbers.
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DC Polarity (SS): Solid-state outputs are DC-only and polarity-sensitive—reverse polarity destroys the MOSFET.
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Missing T/C Channels: Only 4 thermocouple inputs (channels 1–4). Channels 5–8 are physically absent.
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Tachometer Wiring: Use shielded twisted-pair cable. Connect shield to designated terminal—not at the fan end.
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No Hot-Swap: Always depower the rack before insertion/removal.
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Slot Assignment: Install in slots 8–10 (auxiliary I/O).
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CPU Dependency: If backplane communication is lost, the board defaults to 100% fan speed—tachometer monitoring disabled in fallback mode.
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Firmware Compatibility: Compatible with all Mark V CPU firmware versions (v3.x and above).

PHOENIX IB ST 24 AI 4/SF-2754309
A-B 1756-TBCH
A-B 1746-IB16


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