Yokogawa SARM15A Mechanical Relay ContactInput Module Configured for dry contact acquisition in CENTUM VP field input architecture, the Yokogawa SARM15A...
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Configured for dry contact acquisition in CENTUM VP field input architecture, the Yokogawa SARM15A (ARM15A Mechanical Relay Contact Input Module) provides direct physical/electrical execution for 32-point relay contact sensing across Yokogawa FIO input subsystems.
The module implements a mechanical relay interface layer between field contact devices and downstream DI modules, translating contact resistance states into defined electrical ON/OFF thresholds under 24 VDC excitation. Redundant-capable field wiring supports dual-line power distribution per 16-point segment, enabling segmented field energization and controlled signal acquisition. Signal integrity is maintained through high off-state impedance discrimination and defined low-resistance ON detection boundaries.
Suffix Breakdown & Model Matrix
SARM15A / ARM15A refers to a fixed mechanical relay contact input module designation within Yokogawa FIO hardware line. No further publicly defined suffix segmentation is specified in the provided technical dataset.
Within Yokogawa FIO input structures, relay-based contact acquisition modules such as SARM15A implement physical channel grouping combined with electrical segmentation per 16-point field power domain. This structure reduces cross-point coupling under 24 VDC excitation conditions, particularly during simultaneous switching of mechanically driven dry contacts. The architecture maintains deterministic ON/OFF threshold interpretation through fixed resistance window discrimination rather than analog scaling methods such as 4-20 mA or HART-based loop evaluation.
Frequently Asked Questions
Q: Can the module be hot-swapped under energized field conditions? A: The module is not designed for field-side hot swapping. Removal requires de-energization of field 24 VDC supply lines and isolation of backplane interface to prevent contact arcing and signal corruption.
Q: What is the electrical interpretation mechanism for ON/OFF states? A: ON state is determined by contact resistance below or equal to 150 ohm. OFF state is defined by resistance equal to or above 200 kohm, forming a discrete threshold window without analog interpolation.
Q: Does the module provide per-channel electrical isolation? A: Isolation is implemented at field power segmentation level and internal circuit isolation barriers, rather than fully independent per-channel galvanic isolation.
Field Installation Guidelines
Ensure 24 VDC field supply is fully isolated before terminal engagement.
Maintain M4 screw torque within standard industrial control cabinet tightening practice to prevent intermittent contact resistance drift.
Route field cables (AKB331) separately from high-noise power conductors to avoid induced switching noise on dry contact lines.
Verify insulation resistance before energizing field loop, minimum 10 Mohm at 500 VDC test condition.
Maintain proper grounding of rack frame to reduce common-mode noise coupling into relay detection circuits.
