Model Code Decoding

• D635: Base series, NG06 (Cetop 3) pressure control valveMoog Inc.

• Z: Special specification (custom tuning, enhanced EMC, extended temp)

• 681:

  • 6: Rated flow 40 L/min (Δp=35 bar/land)Moog Inc.

  • 8: Rated pressure 350 bar (max 350 bar, high‑pressure variant)Moog Inc.

  • 1: 3‑way spool, linear, standard overlapMoog Inc.

• E: Revision E, FPM (Viton) seals, enhanced EMC, 24 VDC supplyMoog Inc.

• P16: 16 VDC command signal (±10 V standard, 16 V custom)Moog Inc.

• XX: Factory‑specific tuning (null, gain, response)

• 1: Standard spool configurationMoog Inc.

• AOR: Analog command + Option (Y‑port, 350 bar T)Moog Inc.

• SS2M: Standard mounting (NG06, M5) + FPM seals + 2m cable lengthMoog Inc.

Technical Specifications

• Part Number: D635-Z681EP16XX1AORSS2M

• Valve Size: NG06 (Cetop 3 / ISO 4401‑03)Moog Inc.

• Control Function: 3‑way pressure control, spring‑centered (fail‑safe: A→T, P→B)Moog Inc.

• Rated Flow (Δp=35 bar/land): 40 L/min (±10% tolerance)Moog Inc.

• Max Flow: 50 L/minMoog Inc.

• Operating Pressure:

  • P/A/B ports: 350 bar (5,000 psi)Moog Inc.

  • T port (without Y): 50 barMoog Inc.

  • Y port (optional): 350 barMoog Inc.

• Response Time (0→100% step): ≤12 ms (faster than standard E‑series)

• Hysteresis: <0.1%

• Null Shift (ΔT=55 K): <0.8%

• Linearity: <0.3%

• Electrical:

  • Supply: 24 VDC (19–32 VDC), 1.2 A maxMoog Inc.

  • Command Signal: ±16 VDC (custom P16)Moog Inc.

  • Feedback: 4–20 mA (pressure)Moog Inc.

  • Connector: 6+PE (DIN 43563), IP67 (mated, enhanced)Moog Inc.

• Fluid: Mineral oil (DIN 51524), viscosity 5–400 mm²/sMoog Inc.

• Temperature:

  • Ambient: −20°C to +65°C (extended Z‑series range)Moog Inc.

  • Fluid: −20°C to +85°CMoog Inc.

• Mass: ~2.6 kg (slightly heavier due to enhanced electronics)Moog Inc.

• Seals: FPM (Viton, high‑temp, chemical resistance)Moog Inc.

Interface & Communication Configuration

• Electrical Interface: ±16 VDC analog command + 24 VDC power; 4–20 mA pressure feedbackMoog Inc.

• Feedback: Integrated high‑accuracy pressure sensor (closed‑loop, no external transducer)Moog Inc.

• Mounting: 4‑bolt NG06 (Cetop 3, M5 screws, 8–10 Nm torque)Moog Inc.

• Porting: P, A, B, T + Y‑port (350 bar return) (AOR option)Moog Inc.

Core Functions

1. High‑Pressure 350 Bar: Designed for extreme industrial hydraulic systemsMoog Inc.

2. 40 L/min High Flow: Highest flow in standard D635 seriesMoog Inc.

3. ±16 VDC Custom Signal: Specialized for non‑standard controllersMoog Inc.

4. Enhanced Dynamic Performance: 12 ms response, 0.1% hysteresis

5. Extended Temperature Range: −20°C to +65°C ambientMoog Inc.

6. Y‑Port High‑Pressure Return: 350 bar T‑port capability (AOR)Moog Inc.

7. Z‑Series Special Tuning: Optimized for high‑precision, high‑stress applications

Application Scenarios

• High‑Pressure Hydraulics: 350 bar systems (presses, injection molding)Moog Inc.

• Industrial Test Benches: High‑pressure fatigue testing, component durability

• Metal Forming: Heavy‑duty stamping, forging, and extrusion pressesMoog Inc.

• Oil & Gas: High‑pressure control valves, hydraulic power units (HPUs)Moog Inc.

• Aerospace Testing: High‑pressure hydraulic simulation systems

Compatibility & Key Differences

• Series Compatibility: Interchangeable with D635 NG06 mounting (P/N 640E/671E)Moog Inc.

• D635‑Z681E vs Standard D635‑681E:

  • Z681E: 40 L/min, 350 bar, ±16 V, −20°C→+65°C, IP67, Y‑port (350 bar)Moog Inc.

  • 681E: 40 L/min, 350 bar, ±10 V, −20°C→+60°C, IP65, standard T‑port (50 bar)Moog Inc.

• Replacement: Direct upgrade from D635‑681E (higher performance, custom signal, extended range)