Pilz 774140 PZE 9 Safety Relay Expansion Module (24V AC)

The Pilz 774140 (PZE 9) is a contact expansion module designed for safety-related applications in industrial automation. This expansion module increases the number of available safety contacts in a safety circuit when driven by a base safety unit such as an emergency stop relay, safety gate monitor, or light curtain evaluation device. The PZE 9 is suitable for applications where multiple contactors or output devices need to be controlled by a single safety monitoring circuit, expanding the switching capacity to additional loads without reducing the safety integrity level of the original circuit.

Output Contact Configuration and Ratings

The PZE 9 provides 8 normally open (N/O) safety contacts and 1 normally closed (N/C) auxiliary contact. The eight safety contacts are positive-guided relay contacts that ensure reliable switching even under fault conditions. Contact ratings: voltage AC1 rating of 240 V with maximum current rating of 8 A; contact voltage AC15 rating is 230 V with current rating of 5 A, suitable for controlling AC contactor coils and other inductive loads; DC13 rating at 24 V is 8 A. The auxiliary N/C contact can be used for status indication or monitoring purposes, providing feedback regarding the expansion module's operating state to the control system. Positive-guided operation ensures that if a contact welds, the other contacts cannot return to the normal position, allowing detection of the unsafe condition. The contact material is AgSnO2 with gold flash layer for reliable switching at low voltages and currents.

Input Circuit and Operating Modes

The PZE 9 supports both 1-channel and 2-channel input wiring configurations with or without short-circuit detection. Two-channel operation with cross-circuit detection provides enhanced fault diagnostic coverage for safety gate monitoring applications by monitoring both input channels for consistency. Without short-circuit detection, the module accepts simpler wiring for applications where cross-fault detection is not required. The expansion module is driven by a base unit that provides the safety evaluation logic; when the base unit energizes its internal relays, the PZE 9 outputs follow the same state, creating simultaneous switching of additional contacts. This parallel expansion approach preserves the safety integrity level achieved by the base unit. The module operates without delay-on de-energization, meaning outputs de-energize immediately when the input signal from the base unit is removed. Input circuit response time ensures rapid output de-energization upon safety circuit opening, minimizing hazard exposure time.

Power Supply Specifications

The PZE 9 is designed for operation on 24 V AC supply voltage, with power consumption of 7 VA. The AC power option makes this module suitable for control systems that use 24V AC control voltage rather than DC. For use with DC systems, other models in the PZE series with 24V DC supply are available. The supply voltage type is AC only for this specific model. The terminals are screw-type fixed terminals accepting conductors from 24 AWG to 10 AWG range. The terminal torque specification is as defined for the terminal type. Housing dimensions are 90 mm width, 87 mm height, and 121 mm depth, with a net weight of 600 g. The module is designed for DIN rail mounting within a control cabinet. The housing materials are ABS UL94 V-0 rated plastic for both the lower section and upper part, providing flame-retardant properties.

Environmental and Mechanical Specifications

Operating ambient temperature range spans from -10°C to +55°C, suitable for most industrial control cabinet environments. Humidity rating is 93% RH at 40°C, with condensation not permitted. The module meets climatic suitability requirements per EN 60068-2-78 and vibration requirements per EN 60068-2-6. Overvoltage category rating is III or II depending on installation, with pollution degree 2. Clearance and creepage distances comply with EN 60947-1 requirements for safety-related applications. Protection type for mounting is determined by the control cabinet installation, while terminal protection type is provided by standard terminal construction. The module is suitable for installation in typical industrial environments without special cooling requirements beyond cabinet ventilation.

Standards and Certifications

The PZE 9 safety relay meets applicable international safety standards including EN 60947-5-1 for low-voltage switchgear, EN 60204-1 for safety of machinery, VDE 0113-1, and EN 61000-6-2 for electromagnetic compatibility. Approvals include CCC (China Compulsory Certification), CE (Europe) for conformity with European directives, UKCA (United Kingdom), cULus Listed for North American installations, EAC (Eurasian Economic Union), and TÜV certification for functional safety compliance. The product is intended for use in industrial environments and is not permitted for use in residential or domestic areas where interference with radio and television reception could occur. These certifications validate the module's suitability for safety-related applications in machinery requiring compliance with applicable safety standards.

Integration and Typical Applications

The PZE 9 is suitable for expanding safety circuits in applications including emergency stop installations where multiple contactors must be controlled, safety gate monitoring for machinery with multiple access doors, light curtain evaluation for large protection fields requiring redundant output switching, two-hand control systems, and safety mat monitoring. The addition of 8 safety contacts allows connection of multiple contactors, solenoid locks, or other output devices to a single safety evaluation device. The contact expansion module connects directly to the base safety unit terminals, typically through a dedicated expansion interface or by wiring between the base unit safety outputs and the PZE 9 inputs. The module then provides isolated relay contacts capable of switching loads independently, allowing distribution of safety outputs to multiple machine zones or functions while maintaining the safety performance level of the base unit. The expansion module is installed in series with the base unit outputs, ensuring that the base unit's safety evaluation still controls the expansion module's output state.

Conclusion

The Pilz 774140 PZE 9 safety relay expansion module provides 8 positive-guided safety contacts for expanding safety circuit capacity in 24V AC systems. Its AC supply, modular expansion capability, and safety certifications support integration with base safety relays for emergency stop and safety gate monitoring applications.