Model Definition

• D661 = Series (integrated electronics, 24 VDC, NG10)

• 556C = Spool/sleeve assembly; rated flow 80 L/min @ ΔP=35 bar (standard flow, high‑linearity trim)

• Typical full config example: G080HAAM6NSX2‑C

  • G080 = 80 L/min rated flow & standard response

  • HAAM = Standard hydraulic layout, 24 VDC, ±10 V/±10 mA command, centered null

  • 6 = 6+PE connector, IP65

  • NSX2 = NBR seals, wide temp range, LVDT 4–20 mA feedback

  • C = High‑linearity ServoJet® pilot stage

Technical Specifications

Hydraulic Parameters

• Rated flow: 80 L/min (ΔP=35 bar)

• Max working pressure: 350 bar (P/A/B); 210 bar (internal drain T) / 350 bar (external drain T)Moog Inc.

• Step response: 10–12 ms (0→100%, 210 bar)

• Hysteresis: <0.10%Moog Inc.

• Resolution: <0.05%Moog Inc.

• Null drift: <1.2% (ΔT=55 K)Moog Inc.

• Null leakage: <15 mL/minMoog Inc.

• Fluid cleanliness: NAS 1638 Class 6 / ISO 4406 18/15

Electrical Parameters

• Power supply: 24 VDC (18–32 VDC)Moog Inc.

• Control signal: ±10 V (differential) or ±10 mAMoog Inc.

• Feedback signal: 4–20 mA (LVDT spool position)Moog Inc.

• Connector: 6+PE, IP65Moog Inc.

• Current draw: ≤800 mAMoog Inc.

Physical & Environmental

• Operating temperature: −40 ℃ to +85 ℃

• Weight: approx. 5.7 kg

Interface & Communication Configuration

• Hydraulic interface: P/A/B/T, ISO 4401‑05 (NG10)Moog Inc.

• Electrical interface:

  • Power: 24 VDC, GND, PE

  • Command: ±10 V / ±10 mAMoog Inc.

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

  • Status: Fault alarm outputMoog Inc.

Core Functions

• High‑Linearity ServoJet® Pilot: Optimized for 80 L/min, minimal hysteresis, superior linearity

• Integrated Precision PID Amplifier: Onboard dead‑zone compensation, thermal/overload protection, stable null

• LVDT Closed‑Loop Feedback: Excellent resolution and repeatability for critical motion control

• Fail‑Safe Centering: Spool returns to neutral on power lossMoog Inc.

• 80 L/min Standard‑Flow Precision: Tuned for medium‑sized hydraulic systems requiring accuracy

Application Scenarios

• Industrial automation: Precision CNC machine tools, medium hydraulic presses, injection molding machines

• Test equipment: Structural fatigue testers, vibration simulation tables, actuator test benches

• Metallurgy: Precision tension control, small AGC roll gap control in light mills

• Energy: Wind turbine pitch control (smaller units), marine auxiliary hydraulic systems

Usage & Maintenance

• Installation: Horizontal/vertical mounting; avoid severe vibration/shock

• Fluid: ISO VG46 mineral oil; maintain cleanliness per NAS 1638 Class 6

• Commissioning: Apply 24 VDC; connect ±10 V/±10 mA command; calibrate zero/gain via 4–20 mA feedback

• Maintenance: Check fluid contamination every 3 months; calibrate zero/gain every 6 months; avoid long idle periods at high pressure