Model Code Explanation (D661-4444C)

D661: Series (ISO 4401‑05, 24 VDC integrated electronics, bushing‑type spool)

4: High‑flow platform

44: 440 L/min nominal flow (Δp=35 bar)

4: Medium‑high dynamics (≈9–11 ms step response)

C: High‑stability electronics, enhanced null performance, low drift

(Implied G): Standard zero‑lap spool, linear flow characteristic

Technical Specifications

Part Number: D661-4444C

Mounting: ISO 4401‑05 (NG10), 4‑hole M5, standard T‑port

Control Function: 4‑way/3‑position, spring‑centered, zero‑lap, closed‑loop

Hydraulic

Nominal Flow (Δp=35 bar): 440 L/min (±8%)

Max Operating Pressure (P/A/B): 350 bar (5,000 psi)

Pilot Pressure (X): 21–280 bar (internal P or external X)

T Port Pressure (Y internal): 210 bar; (Y external): 350 bar

Fluid: Mineral oil (DIN 51524), NBR seals (−20 °C to +80 °C)

Temperature: Ambient −20 °C to +60 °C; Fluid −20 °C to +80 °C

Weight: Approx. 5.7 kg

Electrical

Supply: 24 VDC (18–32 VDC), quiescent ≈230 mA, dynamic ≈500 mA

Command Signal: ±10 V differential (10 kΩ impedance)

Feedback Signal: Optional 4–20 mA (integrated LVDT, ±0.02% FS accuracy)

Connector: 6+PE (EN 175201‑804), IP65 (connected)

Step Response (0→100%): ≤9–11 ms @ 210 bar

Hysteresis: <0.25% (closed‑loop)

Linearity: <±0.30%

Resolution: <0.10%

Interface & Communication

Electrical: 6+PE connector; ±10 V command, 24 VDC power, optional 4–20 mA LVDT feedback

Feedback: Single integrated LVDT (full‑stroke closed‑loop, optional)

Ports: P, A, B, T; optional external X (pilot) and Y (return)

Key Features

440 L/min Ultra‑High Flow: Top‑tier flow rating in D661‑05 platform

9–11 ms Balanced Dynamics: Faster than 4443C, smoother than 4439C

C‑Code High‑Stability Electronics: Superior null stability, minimal thermal drift

ServoJet® Pilot: Low hysteresis, robust pressure gain, proven long‑term reliability

±10 V Analog Interface: Broad compatibility with industrial PLCs and controllers

Applications

High‑tonnage hydraulic forging presses

Large‑scale injection molding & die‑casting machines

Steel rolling mills & heavy‑duty industrial test benches

Closed‑loop systems (position/velocity/pressure control)

Hydraulic machinery prioritizing flow + balanced dynamics

Compatibility

Interchangeable with D661‑4436C/4438E/4439C/4443C (same ISO 4401‑05 footprint)

Requires 24 VDC supply, ±10 V controller, ISO 4401‑05 manifold

Drop‑in upgrade for lower‑flow D661‑4209/4196