Model Definition

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

571C = Spool/sleeve assembly; rated flow 90 L/min @ ΔP=35 bar (high‑response, linear trim)

Typical full config example: G090HOGBENCO9

G090 = 90 L/min rated flow & high frequency response

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

E = 6+PE connector, IP65

N = NBR seals, wide temp range

C = LVDT 4–20 mA feedback

O9 = High‑response ServoJet® pilot stage

Technical Specifications

Hydraulic Parameters

Rated flow: 90 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: 7–9 ms (0→100%, 210 bar)

Hysteresis: <0.10%

Resolution: <0.05%

Null drift: <1.5% (ΔT=55 K)

Null leakage: <15 mL/min

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)

Connector: 6+PE, IP65Moog Inc.

Current draw: ≤750 mA

Physical & Environmental

Operating temperature: −40 ℃ to +85 ℃

Weight: approx. 5.5 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 mA

Feedback: 4–20 mA (spool position)

Status: Fault alarm output

Core Functions

High‑Response ServoJet® Pilot: Optimized for 90 L/min, fast step response, excellent dirt tolerance

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

LVDT Closed‑Loop Feedback: High linearity and repeatability for precision motion control

Fail‑Safe Centering: Spool returns to neutral on power loss

90 L/min Balanced Flow‑Dynamics: Tuned for medium‑sized systems needing speed and accuracy

Application Scenarios

Industrial automation: Precision CNC machines, medium hydraulic presses, injection molding equipment

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

Metallurgy: Tension control, light‑duty AGC roll gap control

Energy: Wind turbine pitch control, marine auxiliary hydraulics

Usage & Maintenance

Installation: Horizontal/vertical mounting; minimize vibration

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

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

Maintenance: Check contamination every 3 months; calibrate every 6 months; avoid long idle periods at high pressure