Get now 1786-TNCLXT4A to maintain the legacy and current-generation performance of your ControlNet coaxial infrastructure. The Allen-Bradley 1786-TNCLXT4A is a high-reliability, 4-inch coaxial interconnect cable designed specifically for the ControlNet physical layer. As part of the Series A line of accessories, this cable is engineered to facilitate ultra-short connections between ControlNet modules, such as repeaters and taps, without the signal loss associated with longer, unmanaged cable runs. It features 75-ohm impedance-matched BNC male connectors on both ends, which are factory-terminated to ensure a permanent, high-integrity bond with the RG-6 quad-shielded media. Using the 1786-TNCLXT4A is a best practice for clean cabinet design and deterministic network stability, protecting your data from the electromagnetic interference common in heavy industrial manufacturing zones.
What Is the 1786-TNCLXT4A?
The 1786-TNCLXT4A serves as a critical bridge in modular ControlNet systems. It is used primarily to link adjacent ports in a repeater rack or to connect redundant media components where physical distance is minimal. The «A» in the part number signifies its lineage in the Series A production, ensuring compatibility with legacy ControlNet hardware while meeting modern high-speed data requirements. In a deterministic network like ControlNet, every inch of cable adds to the propagation delay. By using the 1786-TNCLXT4A, technicians can keep these delays to an absolute minimum, which is essential for maintaining a fast Network Update Time (NUT) in multi-node configurations.
Key Technical Specifications
- Part Number: 1786-TNCLXT4A
- Manufacturer: Allen-Bradley / Rockwell Automation
- Cable Length: 4 inches (10.16 cm)
- Connector Type: Male BNC (Factory Crimp)
- Impedance: 75 Ohms
- Cable Grade: Industrial Quad-Shielded Coax
- Series: Series A
- Protocol: ControlNet 5 Mbps
- Environmental: Industrial grade PVC jacket, chemical and oil resistant
Applications in Industrial Repeater Systems
In a typical 1786-RPA repeater setup, multiple repeater modules (fiber or coax) are placed side-by-side. The 1786-TNCLXT4A is the preferred method for «daisy-chaining» these units to extend the network segments. Its quad-shielding ensures that even when the cable is located close to other electronic modules, the signal remains free from crosstalk and external RFI. This cable is an essential item for any spare parts kit for facilities relying on ControlNet for their mission-critical automation.
Maintenance Tips
Because the 1786-TNCLXT4A is used in high-density areas of a control rack, it is prone to being bumped during other maintenance activities. Periodically check that the BNC locking rings are tight and have not vibrated loose. An expert maintenance tip: check the BNC connectors for any «play» or wiggle. If the connector feels loose against the cable jacket, the internal shield bond may be failing, which can lead to intermittent signal noise. If you notice any discoloration on the nickel-plated body, clean it with a contact cleaner to ensure a low-resistance path for the cable shield, which is vital for EMI rejection. Replacing a questionable jumper cable is always cheaper than diagnosing a network crash.
Frequently Asked Questions
Q: What is the difference between 1786-TNCLXT4 and 1786-TNCLXT4A?
A: The «A» version typically refers to the Series A manufacturing run. Electrically and functionally, they are designed to be equivalent 4-inch 75-ohm interconnects, but certain plant standards may require matching the specific series of the existing hardware.
Q: Can I use this cable for a ControlNet drop connection to a drive?
A: Generally no. A 4-inch cable is far too short to reach from a tap to a drive or PLC module in a standard layout. You should use a 1786-CP or 1786-TNCL series cable of at least 1 meter for those applications.
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