The Allen-Bradley 1757-FFLD2, also cataloged as the 1757-FFLD2 Fieldbus Linking Module, operates as a dedicated hardware component for bridging FOUNDATION Fieldbus H1 networks to high-speed Ethernet backbones within ControlLogix system architectures.

Product Variants & Identification

The Allen-Bradley 1757-FFLD2 bridges fieldbus device segments directly to higher-level automation networks. Spare catalog representations include the 1757FFLD2 and revision designation 1757-FFLD2/A. The module integrates up to four H1 FOUNDATION Fieldbus channels and a single 10/100 Mbps Ethernet connection to process process-level field data.

Electrical & Operational Specifications

Deterministic Network Bridging & Firmware Execution

The module manages data translation between FOUNDATION Fieldbus H1 field devices and EtherNet/IP deterministic networks without introducing system latency. Firmware flash compatibility allows remote updating of protocol stacks over the Ethernet interface. Optimized memory mapping maintains high-speed backplane bus communication velocity when transferring fieldbus blocks to the main controller image, while flexible configuration scaling accommodates up to 64 field instruments per linking module.

Delivery Package Contents

• 1 x 1757-FFLD2 Fieldbus Linking Module
• 1 x Protective Static Shielding Bag
• 1 x Terminal Connector Block Kit

Hardware Mounting & Wiring Rules

• Disconnect input power sources before handling or mounting the module to prevent electrical shock or equipment damage.
• Mount the module securely onto standard DIN rail or chassis infrastructure inside a protected control enclosure.
• Terminate H1 fieldbus segments using approved shielded twisted-pair cables with 100-ohm line terminators at both ends of the trunk.
• Connect low-impedance ground bonding wires directly from the shield terminal to the central enclosure earth ground bus.
• Route Ethernet lines and low-voltage fieldbus signal leads away from high-voltage motor circuits and variable frequency drives.

Technical FAQ

• What supply voltage and current does the 1757-FFLD2 require?

  The module operates on 24 VDC power, drawing a nominal current of 300 mA under standard operation and a maximum current of 1.5 A.

• How many FOUNDATION Fieldbus devices can connect to a single H1 channel?

  Each H1 physical interface supports up to 16 fieldbus devices, though 8 to 10 devices per segment are recommended for optimal scan times.

• What is the total device capacity for one 1757-FFLD2 module?

  The module can aggregate and manage data from a maximum of 64 FOUNDATION Fieldbus devices across all integrated H1 channels.

• What network interface provides communication to the ControlLogix system?

  Primary connectivity to the supervisory system is provided via a standard 10/100 Mbps RJ45 Ethernet port.

• How are fieldbus cable shields properly grounded on this module?

  Cable shields should be connected to the dedicated ground terminal and bonded to earth at a single point to prevent ground loop noise.

• What thermal limits must be observed during module operation?

  The unit is specified for continuous operation within ambient temperature limits ranging from 0 deg C up to 60 deg C.

• Can the firmware on the 1757-FFLD2 be upgraded in the field?

  Yes, firmware flash compatibility permits field updates over the local Ethernet communication port using standard configuration tools.

• What relative humidity conditions are acceptable for operation?

  The module operates in relative humidity environments ranging from 5% to 95%, provided the air remains noncondensing.