Yokogawa SARM15A Relay Board

Configured for digital input acquisition in CENTUM VP and ProSafe-RS systems, the Yokogawa SARM15A-00 (SARM15A Relay Board) provides direct physical signal routing between field-side dry contacts and system I/O modules.

Hardware Specifications

DCS Signal Processing and Isolation

The SARM15A serves as an interface for field signal acquisition, facilitating the connection between discrete sensors and digital input modules such as the ADV151 and ADV161. The unit maintains signal integrity by employing channel-to-channel isolation architecture, which prevents electrical noise from propagating into the DCS backplane. During operation, the board manages dry contact signals via 24 VDC excitation, ensuring compatibility with standard industrial limit switches and relay status feedback. The design prioritizes the suppression of common-mode interference through robust dielectric strength between the field terminals and the internal power rails.

Frequently Asked Questions

Q: Does the SARM15A provide internal surge protection for the field inputs?

A: The board provides dielectric isolation (1.5 kV) to protect against high-voltage transients; however, it does not include active surge suppression components. External lightning protection or surge arrestors should be installed in the field junction box if the wiring exits the control cabinet or traverses high-EMI environments.

Q: Can this board be used for wet-contact (voltage-sourced) signals?

A: No. The SARM15A is specifically engineered for dry-contact/mechanical relay input acquisition. Applying external voltage to the input terminals may result in hardware damage to both the terminal board and the connected digital input module.

Q: How should I manage redundancy when wiring to the ADV161 module?

A: The SARM15A supports both single and dual-redundant configurations. Ensure the appropriate interface cables (e.g., AKB337) are utilized to map the 32-point field inputs correctly across the redundant module pair, maintaining consistent loop status across the I/O bus.

Field Installation Guidelines

• Mounting: The SARM15A is designed for installation in a standard 19-inch cabinet. Utilize all four mounting points to ensure frame stability within the 3U rack space.
• Grounding: Secure the board chassis to the system common ground bus using a multi-strand copper conductor. A low-impedance ground connection is mandatory to achieve the rated 1.5 kV isolation between field terminals and the enclosure.
• Termination: Utilize M4 screw-type terminals for field wiring. Ensure that wire ferrules are used for stranded conductors to prevent strand fraying and ensure a secure, gas-tight electrical connection.
• Cable Management: Route signal cables through the cabinet wireways, ensuring a minimum separation of 100 mm from high-voltage AC power cabling to reduce electromagnetic coupling and input noise floor levels.