Allen-Bradley 1769-L24ER-QBFC1B CompactLogix 5370 L2 Controller

Configured for high-speed logic control, integrated safety signaling, and field instrument data processing in industrial Ethernet networks, the Allen-Bradley 1769-L24ER-QBFC1B (1769-L24ER-QBFC1B Programmable Automation Controller) provides direct physical/electrical execution across CompactLogix 5370 L2 platforms.

Hardware Specifications

EtherNet/IP Deterministic Networks & Firmware Execution

The controller incorporates dual EtherNet/IP ports with embedded Device Level Ring (DLR) functionality, guaranteeing deterministic network communication and fault-tolerant ring topologies without third-party switches. Internal microprocessor logic coordinates field I/O execution with the 750 KB user memory allocation while executing task scheduling at high speed. Firmware flash compatibility allows seamless system synchronization over backplane bus connections and network nodes. The integrated ASIC manages I/O density scaling across the embedded 16 DC inputs, 16 DC outputs, 4 universal analog inputs, 2 analog outputs, and 4 high-speed counters, maintaining real-time processing performance under high backplane traffic conditions.

Frequently Asked Questions

Q: How many local 1769 Compact I/O expansion modules can be connected to this controller?

A: The controller supports a maximum of 4 local 1769 Compact I/O expansion modules within a single I/O bank. Adding modules beyond this limit exceeds backplane signaling thresholds and controller addressing limits.

Q: What network topologies are supported by the dual EtherNet/IP ports on this module?

A: The dual EtherNet/IP ports support Linear, Star, and Device Level Ring (DLR) topologies. When configured for DLR, the controller provides media redundancy, recovering network connection traffic within milliseconds if a single cable break occurs.

Q: What nonvolatile memory options are supported for project backup and restore operations?

A: The unit includes a 1 GB 1784-SD1 Secure Digital card and supports up to a 2 GB 1784-SD2 card. You can configure the controller to load the user application from the SD card automatically upon power-up.

Field Installation Guidelines

Mount the controller securely on an IEC standard DIN rail or panel surface within a grounded metallic enclosure. Verify that the ambient operating temperature inside the cabinet remains between 0 and 60 deg C during operation.

Connect the dedicated 24 VDC external power supply to the embedded power terminal block using copper conductors rated for standard industrial temperature limits. Ensure power wiring stays separated from high-voltage AC lines to minimize electromagnetic noise coupling.

Establish low-impedance earth ground connections using heavy-gauge grounding straps connected directly to the chassis ground point. When landing wiring for universal analog inputs and high-speed counters, use shielded twisted-pair cables and ground the cable shields at a single chassis point to preserve signal integrity and eliminate ground loops.