The Yokogawa ARM55D‑000, also cataloged as the ARM55D relay board, operates as a dedicated dry‑contact output component for mechanical relay actuation within CENTUM‑series I/O networks.
Hardware Specifications
Parameter
Specification
Model
ARM55D‑000
Brand
Yokogawa
Origin
Not specified
Weight
2.2 kg (shipping: 3 kg)
Dimensions
18.4 cm × 48.2 cm × 13.2 cm
Operating Temp
Not specified
Power Consumption
Not specified
Product Type
Relay Board
Contact Type
Mechanical relay dry contact, “a” contact (NO)
Redundancy
Single / dual‑redundant
Contact Points
32‑point
Field Terminals
M4 screw terminals
Insulation Resistance
≥ 10 MΩ at 500 V DC
Mounting
19‑inch rack mountable
Model Definition
ARM55D = 32 dry contact outputs
4‑20 mA HART Loop Protocol & Channel‑to‑Channel Isolation
Although ARM‑series relay boards do not process analog loops directly, Yokogawa’s DCS hardware design applies the same isolation principles used in HART and Fieldbus subsystems. Each of the 32 dry‑contact channels is mechanically isolated, preventing cross‑channel interference when switching inductive or capacitive field loads. The board’s M4 terminal layout maintains separation distances that reduce noise coupling from adjacent circuits. Relay actuation paths follow deterministic isolation rules similar to those used in FOUNDATION Fieldbus segment protection, ensuring stable switching behavior in redundant architectures.
Frequently Asked Questions
Q: Can the ARM55D‑000 be hot‑swapped? A: No. Relay boards must be inserted or removed only when the I/O segment is de‑energized to avoid unintended contact transitions.
Q: Does the board support mixed contact types? A: No. ARM55D‑000 provides 32 NO dry‑contact outputs only.
Q: Are the terminals suitable for larger field conductors? A: Yes. M4 screw terminals support typical control‑room wiring gauges used for relay and interlock circuits.
Field Installation Guidelines
Mount the board in a 19‑inch rack using the designated hardware to ensure correct alignment with adjacent I/O modules.
Route relay output wiring separately from analog loops to prevent impedance coupling.
Maintain shield continuity and terminate shields at a single grounding point to avoid ground‑loop interference.
Verify torque on M4 terminals to ensure stable mechanical retention under vibration.
Inspect relay contact groups during commissioning to confirm correct NO contact behavior and redundancy configuration.
