Product Overview
The Pilz PNOZ X3 is a standalone safety relay designed to monitor emergency-stop pushbuttons, safety gates and other safety-related switching devices.
It provides redundant, internally monitored safety circuitry. When an emergency-stop button is pressed, a safety gate is opened or a wiring fault is detected, the relay removes power from its safety outputs and commands the connected machinery to stop.
The 774310 model operates from either 24 VAC or 24 VDC and includes three normally open safety contacts, one normally closed auxiliary contact and one semiconductor status output.
Technical Specifications
| Specification | Details |
|---|---|
| Supply voltage | 24 VAC or 24 VDC |
| Supply tolerance | Approximately 20.4–26.4 VDC |
| Input configuration | Single- or dual-channel |
| Cross-short detection | Supported with correct wiring |
| Safety contacts | 3 normally open |
| Auxiliary contact | 1 normally closed |
| Semiconductor output | One status output |
| Start modes | Automatic or monitored/manual start |
| Feedback-loop monitoring | Supported |
| Contact material | Silver-tin oxide, AgSnO₂ |
| Contact rating, AC-1 | Maximum 8 A at 240 VAC |
| Contact rating, DC-1 | Maximum 8 A at 24 VDC |
| Contact rating, AC-15 | Maximum 5 A at 230 VAC |
| UL pilot-duty rating | B300/R300 |
| Terminals | Integrated screw terminals |
| Mounting | 35 mm DIN rail |
| Housing width | 45 mm |
| Housing protection | IP40 |
| Terminal protection | IP20 |
| Ambient temperature | Approximately −20°C to +55°C |
| Relative humidity | Maximum approximately 93% at 40°C |
| Condensation | Not permitted |
| Overvoltage category | III/II, depending on circuit |
| Pollution degree | 2 |
Contact Arrangement
| Contact type | Quantity | Purpose |
|---|---|---|
| Normally open safety contacts | 3 | Switching contactors or safety shutdown circuits |
| Normally closed auxiliary contact | 1 | Status indication or monitoring |
| Semiconductor output | 1 | Electronic status signal to PLC or monitoring system |
The auxiliary and semiconductor outputs must not be used as safety outputs unless specifically permitted by the approved circuit design.
Main Safety Functions
- Emergency-stop monitoring
- Safety-gate monitoring
- Limit-switch monitoring
- Single-channel input supervision
- Dual-channel input supervision
- Detection of shorts across input channels
- External contactor feedback monitoring
- Automatic restart
- Monitored/manual restart
- Redundant safety shutdown
- Internal relay-contact monitoring
- Fault indication through LEDs and status outputs
Operating Principle
When the supply voltage is available and the safety-input channels are closed, the relay becomes ready for operation.
After a valid automatic or monitored start command:
- The internal safety relays energise.
- The three normally open safety contacts close.
- Connected contactors or machine-control circuits are enabled.
- The status output indicates that the safety circuit is healthy.
If an emergency stop is activated, a safety gate opens or a fault is detected:
- The internal safety relays de-energise.
- The three safety contacts open.
- Power is removed from the controlled contactors.
- The machinery is commanded to enter a safe state.
- Restart is prevented until the safety condition and reset requirements are satisfied.
Safety Performance
When installed in an appropriately designed and validated circuit, the PNOZ X3 can support safety systems up to:
| Safety standard | Maximum achievable level* |
|---|---|
| EN ISO 13849-1 | Category 4 |
| EN ISO 13849-1 | Performance Level e |
| IEC 62061/IEC 61508 | SIL 3 |
*The achievable safety level depends on the complete circuit, input devices, output contactors, wiring, diagnostics and validation—not only the safety relay.
Status Indicators
The front LEDs provide operating and diagnostic information, including:
- Power-supply status
- Safety-input channel condition
- Safety-output/contact condition
- Reset or operating status
These indicators assist technicians during testing and fault diagnosis.
Marine, Offshore and Industrial Applications
- Emergency-stop systems
- Engine-room workshop machinery
- Deck cranes and lifting equipment
- Hydraulic-power packs
- Mooring winches
- Anchor windlasses
- Cargo-handling machinery
- Watertight-door control systems
- Boiler and incinerator safety circuits
- Pump and compressor skids
- Conveyor systems
- Fabrication machinery
- Rotating-equipment guards
- Machine-room access gates
- Retrofit safety-control panels
