Yokogawa PFCD-S5520 Field Control Station

The Yokogawa PFCD-S5520, also cataloged as the PFCD-S5520 Field Control Station Rack, operates as a dedicated hardware component for process control and real-time execution within Yokogawa Centum CS and Centum VP distributed control system (DCS) platforms.

Hardware Specifications

Process Control & Channel Isolation

The PFCD-S5520 executes low-level control loop algorithms and interfaces directly with localized fieldbus environments:

• 4-20 mA HART Loop Integration: The platform architecture supports analog processing modules with integrated HART protocol pass-through, enabling digital device diagnostics to run concurrently over the standard 4-20 mA hardware connections.
• Channel-to-Channel Isolation Protection: Associated input/output card nests installed within the PFCD-S5520 rack maintain galvanic isolation to prevent differential field-loop surge voltages from disrupting core processing cards.
• Cold Junction Compensation (CJC): Direct thermocouple input modules situated in the extension racks handle automated CJC locally, ensuring high-accuracy temperature measurements are transmitted to the redundant CPU processors.

Frequently Asked Questions

Q: What happens to the memory state if main power to the station is lost?

A: The PFCD-S5520 features a built-in battery backup circuit. It retains the contents of the main volatile memory for a maximum of 72 hours during a power disruption, requiring a minimum recharge time of 48 hours once power is restored.

Q: Does this rack support dual-redundant (duplexed) control cards?

A: Yes. The "PFCD" designation represents a duplexed architecture. It accommodates redundant power supply cards, redundant CPU cards, and redundant control bus interfaces (V net).

Field Installation Guidelines

• Rack Grounding Requirements: Ground the rack using a dedicated M4 screw terminal connection. The grounding wire must connect to a single-point instrument earth system with a ground resistance of less than 100 Ohms.
• Wiring Separations: Keep low-voltage DC signals and communication lines physically isolated from incoming AC power supply lines. Use segregated metallic conduits or wire trays to prevent inductive noise.
• Insulation Bush Usage: Utilize the standard insulation bushes (accessories) during 19-inch rack mounting to ensure the physical frame is electrically isolated from the main structural cabinet metalwork.
• Heat Dissipation Spacing: Maintain clean airflow pathways above and below the rack assembly to prevent hot spots, ensuring the surrounding ambient temperature inside the cabinet remains below 60 deg C.