Allen-Bradley 1786-TPYS ControlNet Coaxial Tap

Allen-Bradley 1786-TPYS ControlNet Coaxial Tap

The Allen-Bradley 1786-TPYS, also cataloged as the 1786-TPYS ControlNet Coaxial Y-Tap, operates as a dedicated hardware component for passive physical layer media tapping within ControlNet RG-6 coaxial network topologies.

Suffix Breakdown & Model Matrix

• 1786: Allen-Bradley physical layer media accessories bullet family for ControlNet communication systems.
• TPY: Y-tap structural orientation allowing dual coaxial trunk access ports with a single drop connection.
• S: Straight connector orientation housing design with an integrated 1 m drop cable terminate.

Hardware Specifications

Deterministic Network Backplane & Signal Integrity

The 1786-TPYS provides deterministic ControlNet media passive coupling, maintaining tight 75-Ohm impedance matching across 5 Mbps transmission loops. This physical tap minimizes signal insertion loss and prevents impedance discontinuity reflections that cause media fault alarms. The drop cable structure ensures high physical channel separation and backplane bus communication velocity compatibility without degrading signal-to-noise ratios across multi-node trunk configurations.

Frequently Asked Questions

Q: Does the 1786-TPYS tap require an external power supply to operate?

A: No, the 1786-TPYS is a completely passive physical layer device that couples RF signals directly through matched impedance circuitry without drawing current from the backplane or external supply.

Q: How should unused trunk ports on the 1786-TPYS be handled if located at the end of a physical segment?

A: Any open, unused trunk connector on a end-of-line tap must be closed using a standard 75-Ohm coaxial terminator (such as the Allen-Bradley 1786-XT) to prevent signal reflections across the network.

Q: Can the 1786-TPYS be hot-swapped while the ControlNet network is transmitting data?

A: Disconnecting the trunk connections will break the physical bus topology and disrupt communication downline. However, disconnecting or reconnecting the device node drop cable BNC connector will not interrupt trunk signal continuity.

Field Installation Guidelines

1. Mount the tap securely to a DIN rail or enclosure panel surface using standard hardware before attaching heavy coaxial trunk lines to prevent strain on the BNC connectors.
2. Maintain a minimum bend radius of 75 mm for the RG-6 coaxial trunk cable and the integrated 1 m drop cable to avoid structural core damage and impedance alterations.
3. Torque all BNC twist-lock connections firmly by hand to ensure a low-resistance outer shield connection for solid grounding and signal shielding.
4. Ensure the coaxial outer shield is tied to ground at a single dedicated earth location per network segment to reduce ground loop interference.
5. In redundant ControlNet applications, run Trunk A and Trunk B cables through separate physical conduits to prevent simultaneous mechanical or environmental damage.