1. Product Model

2. Brand

3. Product Category

4. Alias

• Official：S‑2 Control Board

• Common：Drive Main Controller Card, System Logic PCB, S‑2 Drive Control Module, DC Drive Master Board

5. Basic Information

• Manufacturer：Reliance Electric, USA

• Structure：19” rack‑mount plug‑in card, long‑edge backplane connector

• Status：Obsolete / Discontinued（legacy maintenance spare part）

• Dimensions：Approx. 4” × 5”（102 mm × 127 mm）

• Features：Integrated logic circuits, signal processing, fault detection, regulation control, LED status indicators, trim pots for calibration

• Revision：Base version（no suffix）; compatible with S‑2 series DC drives

6. Function & Positioning

• Core Function：Master control and logic processing for Reliance S‑2 series industrial DC drives；executes speed regulation, current limiting, fault monitoring（overvoltage/overcurrent/overtemperature）, and signal coordination between regulator, feedback, and power supply boards；processes reference signals and tachometer feedback to maintain precise speed control；enables system configuration, calibration, and diagnostic functions.

• Positioning：Central logic & control hub for S‑2 DC drive systems；works with 0-51901‑A (armature regulator)、0-51902‑5A (speed feedback)、0-51903‑A (auxiliary power) to form a complete high‑performance DC speed control system.

7. Core Performance Parameters

• Input：±15 VDC (logic), +24 VDC (control) from auxiliary power board

• Control Signals：0‑10 VDC speed reference, tachometer feedback (0‑50 VDC)

• Regulation Accuracy：±0.1% speed regulation

• Response Time：< 10 ms

• Operating Temp：0°C ~ +55°C

• Storage Temp：-40°C ~ +85°C

• Protections：Overvoltage, overcurrent, short‑circuit, overtemperature, tach loss detection

8. General Matching Accessories

• Armature regulator board：0-51901‑A

• Speed feedback board：0-51902‑5A

• Auxiliary power supply board：0-51903‑A

• Field controller board, main logic board, gate trigger board, shielded cables, rack mounting hardware

9. Applicable Equipment & Industry

• Equipment：Reliance S‑2 series industrial DC drives, MaxPak/PRL series DC drive systems, heavy‑duty spindle drives, coil winders

• Industries：Metallurgical rolling mills, papermaking machines, mining conveyors, heavy machine tools, textile lines, printing presses, industrial constant‑torque speed regulation systems