Product Description
The 71728 Zener Barrier Z728 (Z728) is an industrial intrinsically safe safety barrier used in automation and process control systems to protect equipment installed in hazardous (explosive gas) areas. It limits voltage and current coming from the safe area so that only a safe energy level reaches field devices like transmitters, sensors, solenoids, and switches, preventing ignition in Ex-rated environments. It is a single-channel DIN rail-mounted Zener barrier, commonly used in oil & gas, chemical plants, and industrial safety systems where intrinsic safety protection is required.
Key Features
• 1-channel Zener barrier module
• Intrinsic safety protection for Ex areas
• Limits voltage to approx. 26.5V safe level
• Current limiting via internal fuse (50mA typical)
• DIN rail mounting for control panels
• Positive polarity DC version
• Suitable for hazardous area signal isolation
• High-reliability industrial safety device
Specifications
• Product Type: Zener Safety Barrier
• Model: 71728 / Z728
• Manufacturer: Pepperl + Fuchs (commonly)
• Channels: 1 channel
• Working Voltage: ~26.5V (10 µA condition)
• Series Resistance: up to ~300–327 Ω
• Fuse Rating: 50 mA
• Mounting Type: DIN rail
• Protection Type: Intrinsic Safety (Ex ia)
• Operating Temperature: approx. -20°C to +60°C
• Application: Hazardous area signal protection for sensors, transmitters, solenoids, and control circuits

