OVERVIEW

Official designation: Allen-Bradley 1788-FBJB6 (1788 Linking Devices, FOUNDATION Fieldbus Junction Box)

Role/Application: This 6-way intelligent junction box provides fault-tolerant connectivity for process automation, linking multiple field devices to a FOUNDATION Fieldbus H1 network, and ensuring bus operation integrity.

KEY SPECS SUMMARY

Power: 12 to 32V DC operating voltage, 40 mA max at 24V

Interfaces / Ports: One Bus-Input, one Bus-Output, six current-protected drops

Indicators: Green (Normal), Red (Over-current fault), Off-Red (Previous fault)

Operating Temp: 0 to 50 degrees C

Platform / Compatibility: FOUNDATION Fieldbus H1, Profibus PA, DIN Rail Mount

Limit: IP20 enclosure rating, 15g shock resistance

Lifecycle: Current Product

FREQUENTLY ASKED QUESTIONS

Technical Specifications:

Q: What is the maximum number of field devices that can be connected to the junction box?

A: The 1788-FBJB6 supports connectivity for a maximum of six field devices via drop-line ports.

Wiring & Installation:

Q: What is the recommended wire size for the fieldbus cable trunk connections?

A: The junction box supports a fieldbus cable size of 18 AWG maximum or 24 AWG minimum.

Troubleshooting & Compatibility:

Q: How does the junction box protect the network from a short circuit on a field device drop?

A: It isolates the faulty drop by limiting current and indicating the fault via a constant red LED.

Replacement & Upgrades:

Q: How are the auto-reset features of the drop-line over-current protection configured?

A: Auto-reset intervals (5 minutes, 1 hour, or 12 hours) are set using DIP switches.