The Yokogawa SARM55W-000, also cataloged as the SARM55W-000 Relay Board, operates as a dedicated hardware component for 32-point contact output execution within process control systems.

Suffix Breakdown & Model Matrix

• SARM55W-000: Base designation for a 32-point mechanical relay board, configured for wet contact output operations with support for single or dual-redundant deployment.

Hardware Specifications

Process Control and Signal Isolation

The SARM55W-000 incorporates high-density relay switching, supporting both single and dual-redundant configurations for critical output paths. The board architecture features channel-to-channel isolation to prevent propagation of electrical faults from field devices back to the controller backplane. Galvanic isolation is enforced between the field device terminals and the internal logic circuitry, with a withstand voltage of 2 kV. This isolation profile, combined with the 500 VDC insulation testing capability, ensures deterministic signal path behavior in complex DCS environments.

Frequently Asked Questions

Q: Does the SARM55W-000 support hot-swapping while the system is energized?

A: No. Due to the nature of the mechanical relay contacts and the 24 VDC power distribution, the board must be isolated from the power supply and control bus before any installation or maintenance procedures are performed.

Q: What is the minimum load requirement for the mechanical relay contacts?

A: The contacts require a minimum load of 5 V at 10 mA to ensure stable contact closure and prevent premature oxidation of the mechanical relay surfaces.

Field Installation Guidelines

1. Ensure the board is mounted in a 3U-compliant rack enclosure, maintaining clearance for proper heat dissipation within the 0 deg C to 50 deg C ambient range.
2. Terminate all field signal wires to the M4 screw terminals, ensuring a secure mechanical connection to prevent high-resistance contact points.
3. Verify that the field device power supply is fused appropriately to protect the dual-line input, as the system supports a maximum current of 9.6 A for AC or 30 VDC loads.
4. Maintain separation between high-voltage switching circuits and low-voltage logic signal wiring within the cabinet to prevent inductive noise injection.
5. Check that the insulation resistance exceeds 10 MOhm using a 500 VDC source before initial commissioning to confirm integrity against casing grounds.