Pilz 774350 P2HZ X3 Safety Relay

The Pilz 774350 (P2HZ X3) is a force-guided safety relay designed for monitoring emergency stop circuits, safety gates, and two-hand controls in industrial machinery. It features two normally open (N/O) safety outputs and one normally closed (N/C) auxiliary output. Certified to EN ISO 13849-1 up to Performance Level e (Category 4) and IEC 61508 up to SIL CL3, the P2HZ X3 provides reliable safety switching for demanding applications. The unit is housed in a 45 mm wide enclosure suitable for DIN rail mounting.

Technical Specifications

Supply voltage: 24 V DC (19.2-28.8 V). Power consumption: 2 W. Safety inputs: single or dual-channel with cross-circuit detection. Safety outputs: 2 N/O (force-guided relays) rated at 6 A (230 V AC, AC-15) or 3 A (24 V DC, DC-13). Auxiliary output: 1 N/C (2 A). Response time: ≤ 25 ms. Reset type: automatic or monitored manual (selectable by DIP switch). Temperature range: -10°C to +55°C. Dimensions: 45 mm (W) × 100 mm (H) × 120 mm (D). Protection rating: IP20. The unit has removable screw-type terminals for power, inputs, and outputs. LEDs indicate supply, input status, and output energised.

Key Features

• 2 N/O safety outputs, 1 N/C auxiliary contact

• Force-guided relay contacts (EN 50205)

• Single or dual-channel input configuration

• Cross-circuit detection for dual-channel wiring

• Automatic or monitored manual reset

• Feedback loop (EDM) monitoring of external contactors

• LED diagnostics for quick troubleshooting

• Removable terminal blocks

Safety Functions

The P2HZ X3 is typically used to monitor emergency stop devices (pushbuttons, rope pulls), interlocking guards (hinge or magnetic switches), and safety light curtains. In dual-channel mode, the relay checks both input channels for simultaneous closure and detects shorts between channels. The monitored manual reset ensures that the reset button is released and external contactors have properly de-energised before the safety outputs re-engage. The auxiliary output (N/C) provides status feedback to a PLC or indicator lamp.

Wiring and Configuration

Configuration is performed via DIP switches on the front panel. Switch 1 selects operating mode (single/dual channel). Switch 2 selects reset type (auto/manual). Additional switches configure feedback monitoring and cross-circuit detection. Wiring: Connect 24 V DC to A1/A2. Input devices connect to S11/S12 (channel 1) and S21/S22 (channel 2). For feedback loop, connect contactor auxiliary contacts to Y1/Y2. The safety outputs (13-14, 23-24) connect to contactor coils. The auxiliary output (31-32) is for status. All wiring must comply with local safety standards.

Applications

Typical applications include emergency stop systems on CNC machines, injection moulding machines, packaging equipment, and conveyor lines. The relay is also used for safety gate interlocking in robotics cells and for two-hand control on presses. Its force-guided contacts allow it to be used in category 4 safety circuits.

Diagnostics

LEDs: green (PWR) for supply, yellow (I1, I2) for input states, green (K1, K2) for output energised, red (Fault) for error. Fault conditions such as cross-circuit, missing feedback, or shorted reset button are indicated by flashing patterns. The unit stores the last fault in memory.

Environmental and Compliance

CE, UL, TÜV certified. RoHS compliant. Operating temperature -10°C to 55°C, storage -40°C to 85°C. Humidity 10-95% non-condensing. Vibration 2g (10-55 Hz). IP20 front and terminal protection. Must be installed in a control cabinet.

Conclusion

The Pilz 774350 P2HZ X3 safety relay offers a compact, high-integrity solution for safety monitoring in industrial machinery. Its force-guided contacts, flexible configuration, and PL e/SIL CL3 rating make it suitable for a wide range of safety applications.