Pepperl+Fuchs Z787.H Zener Barrier Safe Barrier Module

Z787.H Safe Barrier Module | Pepperl+Fuchs

Product Introduction

The Pepperl+Fuchs Z787.H is a 2-channel Zener Barrier designed specifically for intrinsic safety applications. This DC version features positive polarity and incorporates a diode return path for enhanced protection. The zener diodes connect in the reverse direction, and their breakdown voltage remains unexceeded during normal operation. However, if a fault in the safe area causes this voltage to exceed the threshold, the diodes conduct and blow the fuse, effectively preventing dangerous energy from reaching the hazardous area. This high-power version offers a lower series resistance, which delivers higher voltage to your field devices. The Z787.H serves as an essential safety component for evaluating signals from hazardous areas while maintaining system integrity.

Electrical Specifications and Performance

The Pepperl+Fuchs Z787.H offers precise electrical characteristics for reliable operation. The nominal resistance is 240 Ω, with a maximum series resistance of 250 Ω. The fuse rating is set at 80 mA, providing adequate protection for most field instrumentation. For the supply loop, the maximum working voltage reaches 27 V, while the measurement loop operates at a maximum of 26.5 V at 10 µA. The diode return feature prevents current from flowing back into the hazardous area. Consequently, the current assumption for intrinsic safety calculations becomes zero, simplifying your safety assessment.

Connection and Terminal Configuration

This Zener Barrier provides clear and straightforward terminal assignments. For the hazardous area connection, you use terminals 1, 2 for channel one and terminals 3, 4 for channel two. Meanwhile, the safe area connection uses terminals 5, 6 and 7, 8 respectively. This logical arrangement simplifies wiring and reduces the risk of connection errors. The Z787.H uses screw terminals that accept a maximum core cross-section of 2 x 2.5 mm², ensuring secure and reliable connections for your field wiring.

Mounting and Mechanical Specifications

The Pepperl+Fuchs Z787.H features a modular terminal housing design that simplifies installation. Its compact dimensions measure 12.5 x 115 x 116 mm (0.5 x 4.5 x 4.6 inch) in width, height, and depth. You can mount this unit directly on a standard 35 mm DIN mounting rail per EN 60715:2001, which integrates seamlessly with other K-System components. The unit weighs approximately 150 g and carries an IP20 degree of protection per IEC 60529. Furthermore, the operating temperature ranges from -20 to 60 °C (-4 to 140 °F), with a storage temperature of -25 to 70 °C (-13 to 158 °F).

Hazardous Area Approvals and Safety Compliance

The Z787.H holds extensive international approvals for hazardous area applications. It carries the EU-type examination certificate BAS 01 ATEX 7005 with marking Ⓛ II (1)GD, I (M1) [Ex ia Ga] IIC, [Ex ia Da] IIIC, [Ex ia Ma] I. Additionally, it features TÜV 99 ATEX 1484 X with marking Ⓛ II 3G Ex nA IIC T4 Gc. For IECEx, the certificate numbers are IECEx BAS 09.0142 and IECEx BAS 17.0091X, with marking [Ex ia Ga] IIC, [Ex ia Da] IIIC, [Ex ia Ma] I, and Ex ec IIC T4 Gc. The unit also holds FM and UL approvals with control drawings 116-0118 and 116-0139 (cULus) respectively. Key intrinsic safety parameters include a maximum voltage Uo of 28 V, current Io of 120 mA, and power Po of 830 mW.

Packaging and Logistics

Your purchase of the Pepperl+Fuchs Z787.H includes the Zener Barrier module and a comprehensive quick-start guide. For your convenience, we ship all orders using premium express courier services such as FedEx, UPS, or DHL. This ensures that your critical safety components arrive swiftly and securely, ready for immediate installation in your hazardous area applications.

Frequently Asked Questions (FAQ)

1. What is the primary function of the Pepperl+Fuchs Z787.H?

   • The Z787.H safely limits energy transfer from safe areas to hazardous areas using zener diodes and a fuse.

2. How many channels does the Z787.H provide?

   • This Zener Barrier offers 2-channel operation, supporting two independent signal loops in one compact housing.

3. What does the diode return feature do in this barrier?

   • The diode return prevents current from flowing into the hazardous area, making the current assumption for safety calculations zero.

4. What is the maximum series resistance of the Z787.H?

   • The maximum series resistance is 250 Ω, with a nominal resistance of 240 Ω for normal operation.

5. Which hazardous area approvals does the Z787.H hold?

   • The Z787.H holds ATEX, IECEx, FM, and UL approvals for use in explosive atmospheres with [Ex ia Ga] IIC and Ex ec IIC T4 Gc markings.