Safety relay PNOZ X1 24VAC/DC 3NO 1NC 774300

Application and Function in Safety Systems

This device is a classic safety relay from the PNOZ X1 series, designed to monitor safety-critical functions such as emergency stop buttons (E-STOP) or guard locking mechanisms. It operates based on the principle of redundancy and self-monitoring, meaning that the internal electronics continuously verify the correct operation of contacts in every switching cycle. As a result, even in the event of a single component failure inside the enclosure, the safety function remains effective – the circuit will not allow erroneous machine restart. This is crucial when designing installations compliant with standards EN 60204-1 and IEC 60204-1, where high reliability is required in case of sudden process stoppage.

It is worth noting the specific characteristics of this model: it is not suitable for applications involving optical barriers requiring dynamic start-up, as it lacks the appropriate start-up delay function. However, it is an ideal choice for simple control circuits where the priority is fast and reliable power disconnection in hazardous situations.

Contact Configuration and Mounting Options

The primary advantage of this solution is its flexible output configuration, allowing direct control of contactors or other actuators without the need for additional intermediate relays. The device features three independent normally open (N/O) safety contacts, which are instantaneous contacts. This means that upon activation of the safety function (e.g., pressing the E-STOP), these contacts open immediately, disconnecting power from the load. Additionally, one normally closed (N/C) signaling contact, also instantaneous, is provided on the cover, which can be used for status monitoring or to control visual signaling indicating system shutdown.

Mounting is standard on a 35 mm DIN rail, facilitating integration into narrow control cabinets – the device width is only 22.5 mm. Electrical connections are made via screw terminals, allowing connection of conductors sized for standard industrial applications. The screw tightening torque is 0.60 Nm, ensuring durable connections even under vibrations typical in industrial environments.

Operating Parameters and Environmental Resistance

The device operates with a control voltage of 24 V AC/DC, making it a universal component in installations using both DC power sources (e.g., PLC power supplies) and AC sources (e.g., control transformers). This voltage tolerates fluctuations in the range of -15% to +10%, increasing system resilience against power supply instability. The rated contact current is 8 A at voltages up to 240 V AC or 24 V DC, enabling direct control of smaller contactors or resistive loads without overloading the safety relay contacts.

The contact material is a silver alloy with tin oxide addition and gold plating (AgCuNi + 0.2 µm Au), ensuring low voltage drop and long service life under high numbers of switching cycles. The enclosure is made of PPO plastic meeting UL 94 V0 flammability standards. Protection class IP40 (for the device itself) and IP54 (with proper mounting) protects against dust and water splashes typical in production halls. The operating temperature range is from -10°C to +55°C, covering most conditions in technical rooms without the need for additional cabinet heating or cooling.

Key device parameters include safety category Kat. 2 / PL e / SIL CL 2 and external dimensions of approximately 87 mm height and 121 mm depth, with a module width of only 22.5 mm. Thus, the device occupies minimal space on the distribution rail while maintaining full functionality of three safety outputs and one signaling output in a single V-0 fire-resistant enclosure.