Pilz 787310 PNOZ X3P C Standalone Safety Relay

The Pilz 787310 (PNOZ X3P C) is a standalone safety relay designed for monitoring emergency stop pushbuttons, safety gates, light barriers, and limit switches in industrial machinery. Part of the PNOZ X series, this safety relay provides reliable evaluation of safety input circuits and safe switching of output contacts used to remove hazardous energy from a machine when an unsafe condition is detected. The PNOZ X3P C is suitable for applications up to Category 4 Performance Level e per EN ISO 13849-1 and SIL 3 per IEC 61508/IEC 62061 safety standards.

Input Configurations and Operating Modes

The PNOZ X3P C supports both one-channel and two-channel input wiring configurations, accommodating different safety circuit architectures. In two-channel operation with cross-circuit detection, the relay monitors for shorts across contacts and faults between input channels, providing the diagnostic coverage required for Category 4 applications. Without cross-circuit detection, the relay accepts simpler wiring for applications where cross-fault detection is not required. The relay can be configured for automatic start or monitored manual start. In manual start mode, a separate reset circuit must be closed after the input safety circuit is closed, preventing automatic machine restart after a power failure or after the safety circuit has been opened. This monitored start function requires that the reset circuit be opened and then re-closed to reactivate safety outputs, ensuring intentional operator confirmation of safe conditions.

Output Contact Configuration

The PNOZ X3P C provides three normally open (N/O) safety contacts, one normally closed (N/C) auxiliary contact, and one semiconductor output (SC). The three N/O safety contacts are positive-guided relays designed to de-energize when the input safety circuit opens. These safety contacts can be connected to safety contactors, solenoid valves, or other devices to interrupt hazardous energy. The auxiliary N/C contact can be used to provide feedback to a PLC, to enable a status lamp, or to facilitate interlocking with other devices. The semiconductor output provides an auxiliary signal for monitoring purposes. Positive-guided operation ensures that if a contact welds due to a fault, the other contacts cannot return to their normal position, allowing detection of the unsafe condition. Contact rating for AC-15 and DC-13 loads is suitable for typical safety circuit applications.

Power Supply and Electrical Specifications

The PNOZ X3P C operates on a dual-voltage power supply accepting 24 V AC or 24 V DC, with tolerance of ±20% for DC and ±15% for AC. This flexibility allows the relay to be used in systems where only AC control voltage is available, as well as modern DC-based safety circuits. The contact rating is 6 A at 24 V DC, and 6 A at 240 V AC. The housing dimensions are 101 mm height, 45 mm width, and 121 mm depth. The plug-in spring-loaded terminals provide tool-free wiring, simplifying installation and reducing wiring time. Spring-clamp terminals ensure vibration-resistant connections suitable for machinery applications. The IP40 protection rating requires installation within a control cabinet. The relay is designed for DIN rail mounting in accordance with standard specifications.

Safety Integrity and Approvals

The PNOZ X3P C is certified to meet international safety standards for machinery. The relay complies with EN 954-1 and EN ISO 13849-1, with performance level PL e and category 4 capability when correctly wired and configured. Approvals include UL/cUL for North American installations, EC (CE) for European markets, TÜV certification for functional safety compliance, and CCC for Chinese market entry. These certifications demonstrate the relay's suitability for safety-related applications in machinery worldwide. The product version is identified as 1.3 in available documentation.

Applications for Safety Circuit Monitoring

The PNOZ X3P C is intended for safety monitoring applications including emergency stop pushbutton circuits, safety gate switch monitoring where two switches must be evaluated with cross-circuit detection, light curtain evaluation providing dual OSSD inputs, two-hand control panels requiring simultaneous operator action to initiate hazardous cycles, and limit switch monitoring on moveable guards. The three safety contact outputs allow connection of multiple contactor circuits or redundant switching of a single safety circuit. The relay can be used in new machinery designs or as a replacement in existing installations where safety components must meet current safety standards. Industries using this relay include packaging machinery, metalworking equipment, conveying systems, automated assembly machinery, and robotics cells.

Diagnostics and Status Indication

The relay includes LED status indicators on the front panel, providing visual feedback for power supply presence, input circuit status, and output relay state. These indicators assist with commissioning, troubleshooting, and maintenance by allowing quick verification of relay operating state without measurement equipment. The power supply LED confirms that the supply voltage is within the acceptable range. The input status LED indicates whether the safety input circuit is closed. The output status LED shows the state of the safety contacts. The fault LED indicates detected errors such as input timing errors or cross-circuit faults, allowing rapid diagnosis and repair of safety circuit problems.

Conclusion

The Pilz 787310 PNOZ X3P C standalone safety relay provides reliable monitoring for emergency stop and safety gate applications with 24 V AC/DC supply, three safety contacts, and spring-loaded terminal connections. Its safety certification, configurable input modes, and dual AC/DC power supply support use in industrial machinery requiring compliance with modern safety standards.