Model Definition

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

• 6428E = Spool/sleeve assembly; rated flow 45 L/min @ ΔP=35 bar (high‑response linear trim, with LVDT, standard null, E‑code configuration)

• Typical full config example: G45HOAA6VSM2HA

  • G45 = 45 L/min rated flow & high frequency response

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

  • 6 = 6+PE connector, IP65

  • VSM2 = NBR seals, wide temperature range, standard pilot

  • HA = Fail‑safe centering, with LVDT

Technical Specifications

Hydraulic Parameters

• Rated flow: 45 L/min (ΔP=35 bar)

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

• Step response: 8–12 ms (0→100%, 210 bar)

• Hysteresis: <0.10%

• Resolution: <0.05%

• Null drift: <1.3% (ΔT=55 K)

• Null leakage: <9 mL/min

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

Electrical Parameters

• Power supply: 24 VDC (18–32 VDC)

• Control signal: ±10 V (differential) or ±10 mA

• Feedback: Integrated LVDT (closed‑loop spool position control)

• Connector: 6+PE, IP65

• Current draw: ≤700 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)

• Electrical interface:

  • Power: 24 VDC, GND, PE

  • Command: ±10 V / ±10 mA

  • Feedback: LVDT position signal

  • Status: Fault alarm output

Core Functions

• High‑Response ServoJet® Pilot: Optimized for 45 L/min, fast dynamic response, excellent dirt tolerance

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

• Closed‑Loop Precision Control: LVDT feedback for accurate spool position control, high linearity and repeatability

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

• 45 L/min Medium Flow Dynamics: Tuned for systems requiring balanced speed and accuracy

Application Scenarios

• Industrial automation: Medium‑sized CNC machines, precision hydraulic presses, injection molding equipment

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

• Metallurgy: Precision tension control, medium‑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 and LVDT feedback

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