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YOKOGAWA PW402-S2
Manufacturer: Yokogawa Electric Corporation
Product Introduction:
The PW402-S2 is a 2-channel DC input signal conditioner belonging to Yokogawa’s PW400 series within the FLXA transmitter platform. It is designed to isolate, convert, and transmit DC current signals (4–20 mA) from field instruments to control systems with high accuracy and galvanic isolation. It serves as a critical interface component in distributed control and signal conditioning architectures.
Detailed content
Measurement Principle:
The device receives a 4–20 mA DC input signal from field transmitters or sensors, performs galvanic isolation and signal scaling/conversion, and outputs a conditioned 4–20 mA DC signal to the DCS or PLC. The isolation barrier prevents ground loops and protects downstream equipment from electrical transients.
Technical Specifications:
| Parameter | Specification |
|---|---|
| Model | PW402-S2 |
| Number of Channels | 2 Channels (independent) |
| Input Signal | 4–20 mA DC (2-wire) |
| Output Signal | 4–20 mA DC (2-wire, isolated) |
| Accuracy | ±0.1% of span |
| Isolation Voltage | 1500 V AC (input to output to power) |
| Power Supply | 24 V DC (±10%) |
| Load Resistance | Up to 600 Ω (per channel) |
| Response Time | ≤ 100 ms (typical) |
| Operating Temperature | -10°C to +55°C (+14°F to +131°F) |
| Protection Class | NEMA 4X / IP66 (front panel) |
| Mounting | DIN Rail (35 mm) or Panel Mount |
| Communication | None (standalone signal conditioner) |
| Approvals | CE, UL, CSA |
Structural Features:
- Compact DIN rail or panel-mount housing
- 2 independent channel modules in a single unit
- Screw-terminal connections for easy wiring
- LED status indicators per channel (power, input, output)
- Galvanic isolation barrier between input, output, and power circuits
Performance Parameters:
| Parameter | Value |
|---|---|
| Input Impedance | 250 Ω (typical) |
| Output Impedance | < 50 Ω |
| Common Mode Rejection | ≥ 100 dB |
| Zero Drift | ±0.05% of span / °C |
| Span Drift | ±0.05% of span / °C |
| Insulation Resistance | ≥ 100 MΩ at 500 V DC |
| Dielectric Strength | 1500 V AC, 1 minute |
Key Advantages:
- Galvanic isolation eliminates ground loop errors
- High accuracy (±0.1%) suitable for precision process control
- 2 independent channels in a compact form factor
- Wide operating temperature range for harsh environments
- No external power required for loop-powered configuration
- Easy DIN rail installation reduces wiring complexity
Applicable Industries:
- Oil and Gas (Upstream/Downstream)
- Chemical Processing
- Power Generation
- Water Treatment
- Pulp and Paper
- Food and Beverage
Installation Requirements:
- Mount on standard 35 mm DIN rail or secure to panel with screws
- Maintain minimum 10 mm clearance above and below for ventilation
- Connect input signals using shielded twisted-pair cable
- Ground the cable shield at the control system end only
- Verify 24 V DC power polarity before energizing
- Keep away from high-frequency noise sources (VFDs, radio transmitters)
Usage Precautions:
- Do not exceed 24 V DC ±10% on the power supply terminals
- Do not apply voltage to input or output terminals when power is off
- Verify channel assignment matches the wiring configuration
- Do not short-circuit the output terminals
- Periodically check zero and span calibration per maintenance schedule
- Ensure ambient temperature does not exceed +55°C
