Model Code Decoding

• D651: Base series, ISO 4401 Form A10 (CETOP 5) pQ valve, two‑stage nozzle‑flapper pilot, rated flow 23–35 L/min (Δp=10 bar).

• 129:

  • 1: 4‑way main spool, standard flow/pressure characteristic, internal pilot supply.

  • 2: Pressure rating 350 bar (P/A/B ports), FPM seal material (high‑temperature compatible).

  • 9: Analog interface (0–10 V / 0–10 mA / 4–20 mA), no fieldbus, enhanced firmware for dynamic response.

Technical Specifications

• Part Number: D651-129

• Valve Size: ISO 4401 Form A10 (CETOP 5), port diameter 10.5 mm.

• Control Function: 4‑way pQ control (flow control with superimposed pressure limiting; selectable pressure control mode).

• Rated Flow (Δp=10 bar): 35 L/min (±10%).

• Max Operating Pressure:

  • P/A/B ports: 350 bar.

  • T port: 210 bar (standard); 350 bar optional.

  • Pilot stage: 15–210 bar.

• Response Time: 8–12 ms (0→100% step, 210 bar).

• Hysteresis: <0.8% (flow); <0.2% (pressure).

• Linearity: <0.8% (flow); <0.4% (pressure).

• Electrical:

  • Supply: 24 VDC (18–32 VDC), max current 2.0 A.

  • Command: 0–10 V / 0–10 mA / 4–20 mA (selectable).

  • Feedback: Spool position (0–10 V); pressure (0–10 V).

  • Protection Class: IP65 (mated connector).

• Fluid: Mineral oil per DIN 51524; viscosity 5–400 mm²/s (recommended 15–45 mm²/s).

• Temperature:

  • Ambient: −20°C to +60°C.

  • Fluid: −20°C to +80°C (FPM seals allow up to +100°C intermittent).

• Mass: Approximately 6.6 kg.

• Seals: FPM (standard); NBR/EPDM optional.

Interface & Communication Configuration

• Electrical Interface: Dual analog ports (flow + pressure), 24 VDC power, no fieldbus in standard configuration.

• Feedback: Integrated LVDT for spool position; onboard pressure sensor for closed‑loop pQ regulation.

• Mounting: ISO 4401 Form A10 (CETOP 5) 4‑hole pattern; M6 bolts, torque 12–14 Nm.

• Porting: P, A, B, T main ports; internal pilot supply (port P), external pilot (port X) optional.

Core Functions

1. Combines high‑precision flow control and pressure regulation in one compact unit, reducing system complexity and installation space.

2. 350 bar pressure rating and FPM seals support high‑pressure and elevated‑temperature industrial hydraulic systems.

3. Two‑stage nozzle‑flapper pilot design ensures fast dynamic response and high resolution for demanding applications.

4. Integrated digital electronics enable closed‑loop control with minimal external components and simplified wiring.

5. Selectable pressure control mode allows seamless switching between flow and pressure regulation for versatile operation.

6. Robust IP65 construction ensures reliable performance in harsh industrial environments with dust and moisture exposure.

Application Scenarios

• Used in high‑speed hydraulic presses and metal forming machines requiring synchronized flow and pressure control.

• Applied to precision injection molding machines for accurate speed and clamping force regulation.

• Suitable for hydraulic test benches needing precise flow/pressure profiling and closed‑loop control.

• Deployed in heavy‑duty material handling and die‑casting equipment with high‑force and dynamic requirements.

• Ideal for all industrial hydraulic systems demanding compact, high‑performance pQ control with enhanced temperature tolerance.

Compatibility & Differences

• Basic configuration: 4‑way analog pQ valve, 35 L/min, 350 bar, internal pilot, FPM seals.

• Compared with other D651 models: Variants differ in flow rate (23/35 L/min), seal material (NBR/FPM/EPDM), and electrical interface (analog/fieldbus).

• Interchangeability: Same ISO 4401 Form A10 mounting as other D651/D656 series valves; verify electrical ratings, seal compatibility, and flow characteristics before replacement.