SPW481 for ProSafe-RS Systems | Original Yokogawa

Product Overview

The Yokogawa SPW481 functions as a high-performance AC-to-DC conversion unit specifically engineered for the NFBU series racks within Yokogawa’s Distributed Control Systems (DCS) and Safety Instrumented Systems (SIS). It stabilizes 100-120V AC input into a regulated 24V DC rail, powering critical CPU nodes, I/O modules, and field-bus interfaces. We supply this module as 100% Brand New and Original, featuring advanced environmental protection to ensure uninterrupted operation in corrosive industrial atmospheres.

Part Number Breakdown: SPW481-53

Yokogawa utilizes a specific coding structure to define environmental and safety protections:

• SPW481: 100-120V AC Input Power Supply Module base model.

• 5: Standard type with no explosion protection (Industrial grade).

• 3: Enhanced variant complying with ISA Standard G3 for corrosion resistance.

• S1: Style code representing proven hardware revision for maximum compatibility.

Technical Specifications

The SPW481 provides substantial output capacity and wide-range thermal tolerance:

Engineering Advantages

The SPW481 addresses specific vulnerabilities found in petrochemical and heavy industrial power distribution:

• ISA Standard G3 Compliance: This module features a specialized conformal coating. This chemical barrier prevents "whisker" growth and silver corrosion on circuit traces, which typically occurs in facilities with high concentrations of $H_2S$ or $SO_2$ gases.

• Extended Temperature Performance: Unlike standard supplies that fail at +55 °C, the SPW481-53 operates reliably from -20 °C up to +70 °C. This thermal range permits installation in remote outdoor enclosures or unconditioned control rooms without risking system resets.

• Hot-Swappable Maintenance Logic: The module integrates seamlessly into redundant NFBU racks. If a power fault occurs, the secondary unit carries the full load instantly. Maintenance teams can pull the failed module and insert a new unit while the process remains live, ensuring zero interruption to safety interlocks.

• Regulated Precision for SIS: The SPW481 filters AC line harmonics to deliver a ripple-free 24V DC output. This precision is vital for ProSafe-RS safety systems, where voltage fluctuations could otherwise lead to false trips or sensor signal degradation.

FAQs

Q: Can I use the SPW481 in a 220V AC system?

A: No. The SPW481 is specifically designed for 100-120V AC inputs. For 200-240V AC environments, you must use the SPW482 or PW484 series to ensure hardware safety and proper voltage regulation.

Q: What is the benefit of the "G3" specification?

A: The G3 rating indicates the module can survive "harsh" environments defined by ISA-71.04. It is essential for paper mills, wastewater treatment, and refineries where corrosive gases would otherwise destroy standard electronic components within months.

Q: Does the SPW481 require an external cooling fan?

A: No. The unit utilizes a fanless design with passive convection cooling. This removes a common mechanical failure point and prevents the intake of contaminated air into the module's internal circuitry.

Q: How do I verify the module's redundancy status?

A: Each module features a front-panel "READY" LED. In a dual-power setup, both LEDs should remain illuminated green. If one extinguishes, the system’s RAS (Reliability, Availability, and Serviceability) software will trigger a diagnostic alarm on the Human Interface Station (HIS).