Pilz 475650 PNOZ 1 Safety Gate Relay for Emergency Stop and Safety Circuit Monitoring

The Pilz 475650 (PNOZ 1) is a standalone safety relay designed for monitoring emergency stop circuits, safety gates, light curtains, and two-hand control devices in industrial machinery. This device is part of the PNOZ family of safety relays, which have established a standard for functional safety in machinery protection. The PNOZ 1 provides reliable evaluation of safety input devices and safe switching of output circuits used to remove dangerous energy from a machine when an unsafe condition is detected.

Output Contact Configuration

The PNOZ 1 features 3 safety contacts (normally open outputs) and 1 auxiliary contact (normally closed). 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 output devices to interrupt hazardous energy. The auxiliary N/C contact is typically used to provide feedback to a PLC, to enable a status lamp, or to facilitate interlocking with other devices. Positive-guided operation of all relay contacts ensures that if a contact welds due to a fault, the other contacts cannot return to their normal position, thereby allowing detection of the unsafe condition.

Power Supply and Input Configurations

This model operates on a 230-240 V AC supply voltage, with power consumption of 6 VA. The AC power option makes the PNOZ 1 suitable for control systems that use a 230V AC control voltage and do not have a dedicated 24V DC safety relay power supply. The input circuit supports both 1-channel and 2-channel wiring configurations. Two-channel operation provides higher diagnostic coverage as the relay monitors both circuits for consistency. When configured for single-channel wiring, the relay responds to a single switching signal, which is suitable for lower-risk applications or where cross-circuit detection is not required. The 2-channel configuration without detection of shorts across contacts is the standard operating mode, allowing monitoring of two series-connected safety switches such as guard door switches with separate normally closed contacts.

Reset Modes and Functional Behavior

The PNOZ 1 supports both automatic reset and manual reset (monitored start) operation modes. In automatic reset mode, the safety outputs are activated immediately upon closure of the input circuit as soon as the power supply is established or the emergency stop button is reset. In manual reset mode, the relay requires a separate reset signal after the input circuit is closed, preventing the machine from restarting automatically after a safety intervention. The manual monitor reset function requires that the reset circuit must be opened and then closed to re-activate safety outputs, ensuring that the operator intentionally confirms safe conditions before the machine can restart. This reset behavior is configurable via the terminal wiring, requiring no software configuration or programming.

Safety Integrity and Compliance

The PNOZ 1 is certified for use in safety-related parts of control systems up to the requirements specified by EN ISO 13849-1 and other applicable machinery safety standards. The relay provides safe operation when used in accordance with the wiring examples provided in the operating manual. The device meets the requirements for emergency stop and safety gate monitoring applications where the opening of the safety circuit must cause immediate removal of hazardous energy.

Physical Specifications and Installation

The PNOZ 1 is housed in a 90 mm width enclosure designed for DIN rail mounting inside a control cabinet. The fixed screw terminals accept standard industrial wiring and provide secure connections for power supply, inputs, and outputs. Torque setting for screw terminals is 0.6 Nm. Net weight is 1 lb (approximately 0.45 kg). The enclosure material meets UL 94 flammability requirements. The terminal style is fixed terminal blocks rather than removable connectors. The wide operating temperature range supports installation in typical industrial control cabinet environments. Status LEDs on the front panel indicate power status, input circuit status, and output relay state for local troubleshooting.

Typical Applications

The PNOZ 1 functions as a safety gate relay for machine guarding systems, monitoring from one to two input channels. Typical applications include safety gate monitoring with mechanical switching devices such as interlock switches or hinge switches, emergency stop monitoring with one or two pushbuttons wired in series, two-hand control panels requiring simultaneous operator action to initiate a hazardous machine cycle, and light curtain integration to prevent operator access to hazardous areas while the machine is in motion. The PNOZ 1 is suited to applications requiring 3 safety contact outputs to separately control multiple contactor circuits or to provide redundant switching of a single safety circuit. Industrial segments where this relay is commonly installed include packaging machinery, metalworking equipment conveying systems, and automated assembly machinery.