Yokogawa SARM55C Terminal Board

The Yokogawa SARM55C, also cataloged as the SARM55C Terminal Board, operates as a dedicated hardware component for multi-channel discrete output execution, plant interlock actuation, and field device interfacing within Yokogawa industrial control platforms. Configured with 32 relay output channels supporting Form A or Form C electromechanical variations, the solid-state sub-assembly provides direct physical/electrical execution to convert low-level control signals into isolated, relay-driven outputs natively at the hardware tier.

Hardware Specifications

Process Control & DCS Instrumentation Rails

• Dual-Redundant Architecture Matching and Logic Tracking The terminal board infrastructure integrates directly with single or dual-redundant control configurations inside Yokogawa distributed control system (DCS) architectures. This physical wiring framework allows parallel control signals from redundant output modules to bind to the shared 32-channel terminal matrix simultaneously, maintaining uninterrupted relay state tracking and output execution if an active upstream card channel encounters a circuit fault.
• 4-20 mA HART Loop Protocol Isolation and Suppression Rails While engineered strictly for discrete control tasks such as solenoid activation and motor interlocks, the board operates within dense equipment cabinets alongside sensitive instrumentation running the 4-20 mA HART loop protocol. Complete channel-to-channel and channel-to-system isolation barriers, paired with inductive load suppression components, prevent high-voltage inductive switching spikes and common-mode noise from bleeding into adjacent low-level analog measurement loops.

Frequently Asked Questions

Q: How does the integrated inductive load suppression circuit maintain relay lifespan?

A: Switching inductive field elements like solenoids, contactor coils, or control valves generates a high-voltage back-EMF spike when the relay contacts open. The embedded suppression network clamps these transient voltage peaks natively at the hardware tier, eliminating electrical arcing across the physical contact gaps to prevent pitting, material transfer, and premature contact welding during continuous plant runtime.

Q: What behavioral outcome occurs if the field-supplied 24 V DC power network falls below nominal voltage thresholds?

A: The board relies on an external 24 V DC supply to energize the electromechanical relay coils across the 32 discrete paths. If this external field voltage drops significantly below nominal operational parameters, the internal coil holding force decreases, which can cause contact chatter, intermittent state tracking, or an automated return to the de-energized safe state across all active output loops.