The ELESA CN-SFT is a dedicated safety control unit that functions as a specialized safety relay within the ELESA machine safeguarding ecosystem. While capable of monitoring general safety devices like emergency stop buttons and mechanical interlocks, its design is specifically optimized to work in concert with ELESA's own range of intelligent safety components, most notably the ESC-SFT coded safety handles and CFSW/CFSQ safety hinges. The unit is engineered to meet the rigorous demands of Category 3 and Category 4 safety circuits in accordance with EN ISO 13849-1, providing a reliable and certified interface between safety sensors and the machine's power control system. It is available in two form factors—the standard 35mm width CN-SFT.115 and the space-saving 22.5mm CN-SFT.46—both housed in robust, polyamide-based technopolymer enclosures suitable for DIN rail mounting within industrial control cabinets.

From a functional safety perspective, the CN-SFT is designed for integration into safety systems requiring Performance Level e (PLe) and Category 4, or Safety Integrity Level 3 (SIL 3) as part of a certified architecture. The unit is a dual-channel controller, meaning it monitors the state of two independent contacts from the connected safety device. It is offered in two standard contact configurations: one designed to interface with sensors providing a normally open (NO) and a normally closed (NC) contact pair, and another designed for sensors with two normally closed (NC) contacts. This dual-channel approach, combined with internal cross-monitoring and redundancy, allows the CN-SFT to detect faults such as contact welding, wiring shorts, or signal discrepancies. Upon detection of a safety demand (e.g., guard door opened) or a fault, the unit's two force-guided safety output contacts (13-14 and 23-24) are immediately de-energized, placing the machine in a safe state.

The operational logic of the CN-SFT adheres to the principle of manually monitored start or reset, a fundamental requirement for higher-level safety applications. The safety outputs are activated only after the safety input contacts have reached their correct, safe state (e.g., guard closed) and a deliberate action is performed by the operator—pressing and releasing the external START (reset) button. The unit includes a built-in anti-repeat mechanism; if the START button is stuck or the input contacts are not in the correct state, the safety outputs will not close. This prevents automatic or unexpected machine restart after a safety intervention or power restoration. Front-panel LEDs provide clear visual diagnostics, indicating the status of the power supply and each of the two monitoring channels, which simplifies commissioning and speeds up fault-finding on the factory floor.

In terms of electrical specifications, the CN-SFT is powered by a 24V AC/DC supply with a ±10% tolerance, drawing a maximum current of 220mA on AC and 70mA on DC. The two safety output relays (13-14, 23-24) are rated for 3A at 240V AC (AC-15) and 1A at 24V DC (DC-13), sufficient for directly piloting contactor coils and other control elements. An auxiliary signal contact (41-42 NO, or 41-54 NC depending on model) rated for 0.5A at 24V DC is provided for status feedback to a PLC or other non-safety monitoring system. Installation is restricted to control cabinets with a minimum IP54 protection rating. The device operates reliably up to an ambient temperature of 55°C and carries UL and CE certifications. The ELESA CN-SFT is an ideal solution for machine builders seeking a certified, reliable, and easy-to-integrate safety controller for guard door and emergency stop monitoring applications, particularly within the context of a larger ELESA safety component strategy.

Technical Specifications