MTL 7796- Fieldbus Segment Protector | H1 Short Circuit, 2-Ch, DIN Rail, IS, ATEX/IECEx Specs

MTL 7796- Fieldbus Segment Protector | H1 Short Circuit, 2-Ch, DIN Rail, IS, ATEX/IECEx Specs

MTL 7796- fieldbus segment protector specifications. 2-channel, H1 short circuit protection, intrinsic safety, DIN rail mount. ATEX/IECEx approved for hazardous areas.

Product Overview

The MTL 7796-​ is a fieldbus segment protector​ from MTL's 7700 series, designed to provide short circuit protection​ for FOUNDATION Fieldbus H1 and PROFIBUS PA networks​ in hazardous areas. The dash suffix indicates a specific configuration variant. This device protects fieldbus segments by isolating short circuits​ while maintaining communication on healthy segments, provides intrinsic safety protection, and carries ATEX and IECEx approvals​ for Zone 1 hazardous locations. The segment protector ensures network availability by containing faults to individual segments.

Technical Specifications

Note: Specifications are based on MTL 7700 series documentation. The "7796-" with dash indicates a specific configuration variant. The exact trip current and features may vary by specific model suffix. Always verify with the latest product datasheet.

Key Features

• Fast Short Circuit Protection:​ < 1 µs response time to isolate faults

• Two Independent Channels:​ Protects two separate fieldbus segments

• Auto-Recovery:​ Automatically restores power after fault clearance

• Intrinsic Safety:​ Approved for Zone 1 hazardous locations

• Status Indication:​ LED indicators for power and channel status

• Compact Design:​ DIN rail mounting for easy installation

• Network Availability:​ Maintains communication on healthy segments during faults

• Easy Diagnostics:​ Visual indication of faulted segments

• Global Approvals:​ Certified for international hazardous area applications

• Maintenance-Free:​ No user configuration or calibration required

Protection Characteristics

LED Status Indicators

Typical Network Configuration

[Control System]
       |
[Fieldbus Power Supply]
       |
[MTL 7796- Segment Protector]
       |           |
    Segment 1   Segment 2
       |           |
[Field Devices] [Field Devices]

Entity Parameters (for Hazardous Area Design)

Note: The 7796- is an associated apparatus. Connected fieldbus devices in the hazardous area must be certified as intrinsically safe.

Typical Applications

• Process Plant Fieldbus Networks:​ Protection of critical control loops

• Tank Farm Instrumentation:​ Isolating faults in storage tank monitoring

• Pipeline SCADA Systems:​ Protecting long fieldbus segments

• Offshore Platforms:​ Ensuring network availability in harsh environments

• Power Generation Plants:​ Protecting fieldbus networks in turbine and boiler control

• Water Treatment Facilities:​ Isolating faults in distributed measurement networks

• Any FOUNDATION Fieldbus H1 or PROFIBUS PA network​ requiring high availability and fault containment

Important Technical Notes

1. Installation Location:​ The 7796- should be installed in the safe area or Zone 2, as close as possible to the hazardous area boundary.

2. Power Supply Requirements:​ Requires a 24V DC power supply with sufficient current capacity for all connected segments. The power supply should be rated for the total current of all protected segments.

3. Termination:​ The 7796- does not include termination resistors. Each fieldbus segment requires proper termination (typically 100Ω) at both ends.

4. Cable Faults:​ The unit protects against short circuits between the fieldbus wires. It does not protect against ground faults or cable damage that doesn't create a short circuit.

5. LED Diagnostics:​ Use the LED indicators for quick fault identification. A red LED indicates a short circuit on that segment.

6. Auto-Recovery:​ After a short circuit is cleared, the segment automatically restores power. Investigate and repair the cause of the short circuit before relying on the segment.

7. Certification Compliance:​ Verify that the 7796-'s certifications (specified by the dash suffix) match the hazardous area classification of your application.

8. Network Design:​ The segment protector adds a small amount of series resistance to the fieldbus segment. Consider this in voltage drop calculations for long segments.

9. Testing:​ Test the protection function during commissioning by briefly shorting a segment and verifying the LED indication and auto-recovery.

10. Model Variants:​ The dash suffix indicates a specific configuration. Other suffixes (7796-C, 7796-D, etc.) may have different trip currents, approvals, or features.

Note: This data sheet provides general specifications for the MTL 7796- fieldbus segment protector. For complete installation guidelines, wiring diagrams, and safety instructions, consult the official MTL 7700 Series Technical Manual​ for the specific 7796 variant. Always verify that the product configuration and certifications match your specific application requirements.