HIMA H4135A SIL 3 1oo4D Safety Relay Module

HIMA H4135A Safety Relay Module

The HIMA H4135A, also cataloged as the H4135A Safety Relay Module, operates as a dedicated hardware component for driving safety-critical field actuators within Planar and Modular Safety System architectures. The unit manages 4 independent relay channels with 1oo4D voting architecture to operate 2 Normally Open (NO) switching contacts. Rated for a 24 VDC input supply, the module executes contact switching up to a 5 A maximum load with a response latency under 20 ms. Complete galvanic isolation decouples internal control logic from output switching lines to preserve system signal integrity.

Hardware Specifications

SIL3 Certification & Fail-Safe State Execution

Engineered to comply with SIL 3 under IEC 61508 and PL d under EN ISO 13849-1, the safety relay hardware implements internal 1oo4D redundant circuit paths to guarantee fail-safe state execution during signal anomalies. Complete galvanic isolation suppresses common-mode noise and prevents ground potential shifts from propagating between the field switching contacts and the internal 24 VDC control logic. If power fails or an internal logic fault triggers, the internal armature forces the 2 NO contacts into a de-energized open state within < 20 ms, verifying complete de-energization of connected final control elements.

Frequently Asked Questions

Q: How fast does the module switch to its fail-safe de-energized state upon a safety trip signal? A: The module executes complete contact opening in less than 20 ms following a command transition or power removal.

Q: What contact isolation and switching limits apply to the output channels? A: The 2 Normally Open (NO) output contacts provide galvanic isolation from the internal logic and support a maximum resistive switching capacity of 5 A at nominal system voltage.

Q: How does the internal 1oo4D architecture affect module fault tolerance? A: The 1oo4D arrangement utilizes four internal relay channels with diagnostic monitoring, enabling the system to evaluate fault conditions and execute a deterministic safety trip even if a channel experiences an isolated hardware defect.

Field Installation Guidelines

Mount the unit vertically onto standard DIN rails inside an enclosure rated for IP20 or higher to maintain ambient thermal clearance. Terminate all 24 VDC control power lines and field contact output conductors using properly sized ferrule terminals secured to the screw clamp blocks. Route output field wiring driving high-current inductive loads (such as heavy solenoids or motor starters) in separate grounded metallic raceways away from low-voltage DC logic signaling to avoid inductive noise coupling. Connect the primary panel enclosure ground directly to the central copper earth bus bar with a low-impedance grounding strap to ensure full galvanic isolation performance.