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Yokogawa SDV551-P10
Product Introduction:
The SDV551-P10 is a smart digital valve controller designed to operate pneumatic control valves (globe, butterfly, ball valves) with high precision. It accepts a 4-20 mA control signal from a DCS/PLC and converts it to a proportional pneumatic output signal to the valve actuator. The P10 suffix defines the specific input/output range and diagnostic configuration.
Detailed content
Working Principle:
The SDV551 receives a 4-20 mA DC setpoint signal from the control system. An internal microprocessor compares the setpoint to the actual valve stroke position (measured by a built-in LVDT sensor or external feedback). The controller drives an internal I/P (current-to-pneumatic) converter to generate a proportional air pressure (3-15 psi or 0.2-1.0 bar) to the valve actuator, positioning the valve to match the setpoint. HART communication enables remote configuration, diagnostics, and stroke calibration.
Technical Specifications:
| Parameter | Value |
|---|---|
| Input Signal | 4-20 mA DC (2-wire) |
| Output Signal | 4-20 mA DC to valve positioner OR 3-15 psi (0.2-1.0 bar) pneumatic |
| Stroke Monitoring | Built-in LVDT — 0-100% stroke measurement, ±1% accuracy |
| Communication | HART 7 |
| Power Supply | 24 V DC (loop powered) or 100-240 V AC |
| Air Supply | 1.4-7.0 bar (20-100 psi), clean and dry |
| Ambient Temperature | -20°C to +70°C |
| Protection Rating | IP65 / IP66 (NEMA 4X) |
| Ex Rating | Ex ia IIC T4 Ga / Ex d IIC T6 Gb |
| SIL Rating | SIL 2 (per IEC 61508) |
| Response Time | ≤ 1 second (full stroke) |
| Diagnostics | Stroke monitor, air supply pressure monitor, solenoid valve monitor, travel limit alarm |
| Mounting | Wall mount or pipe mount (DIN clip optional) |
Material Composition:
- Housing: Aluminum alloy die-cast with epoxy coating
- Internal components: Stainless steel, PBT, glass-filled nylon
- Gaskets: Viton (standard)
Advantages:
- Built-in stroke monitoring eliminates need for separate positioner feedback
- HART communication enables remote calibration and diagnostics
- SIL 2 certified for safety-critical valve control
- Compact design — mounts directly on the valve or nearby wall
- Air supply monitoring alerts operators to loss of instrument air
Applicable Industries:
Oil and gas, chemical and petrochemical, power generation, pulp and paper, water treatment, mining, pharmaceutical
Installation Requirements:
- Mount within 30 meters of the valve actuator for optimal response
- Connect 4-20 mA input from DCS/PLC to terminals I(+) and I(-)
- Connect pneumatic output to valve actuator via tubing (max 30 m length recommended)
- Supply clean, dry instrument air at 1.4-7.0 bar
- For HART communication, connect in parallel with the 4-20 mA loop
Usage Notes:
- Perform stroke calibration using HART communicator before initial operation
- Set travel limits to prevent valve over-travel damage
- Monitor air supply pressure — low air pressure will cause valve positioning errors
- Clean air filter regularly — contaminated air damages the I/P converter
- Verify HART communication address is unique on the loop
