Description

Product Overview

The Allen‑Bradley 1485A-C2 is a 121Ω metal film terminating resistor, the official end-of-trunk terminator for DeviceNet industrial bus networks. This precision 1% tolerance, 1/4 watt resistor is installed at the two extreme ends of the DeviceNet trunk cable to absorb signal reflections, eliminating communication noise, data corruption and intermittent dropouts on the differential bus. It resolves common network faults caused by missing or mismatched termination, which lead to unstable node registration and random device disconnections. Automation technicians and network integrators rely on this passive component for commissioning and maintenance of DeviceNet architectures. The through-hole axial resistor is compact and simple to fit inside DeviceNet connectors or junction boxes, maintaining signal integrity across different baud rates and cable lengths for factory automation systems. Word count overview:170

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Technical Specifications

• Product Model: 1485A-C2
• Brand: Allen‑Bradley
• Warranty: One Year
• Input Voltage: Passive component, no external power supply
• Operating Temperature: -40 °C to 85 °C
• Storage Temperature: -40 °C to 85 °C
• Response Time: Passive signal termination
• Protection Class: Epoxy coated axial resistor
• Accuracy Class: ±1% tolerance metal film
• Output Frequency: Not applicable
• Rated Current Range: 1/4 W power rating, 121 ohm
• Communication Interface: Axial leads for wiring to DeviceNet blue/white signal lines
• Supported Protocols: DeviceNet bus termination
• Overload Capacity: Limited by resistor power rating; ESD protected coating
• Dimensions: Axial leaded metal film resistor
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Application Scenarios

• Packaging Machine DeviceNet Network Commissioning: This terminator is fitted at both ends of the DeviceNet trunk connecting VFDs, sensors and remote I/O. The 1485A-C2 suppresses signal reflections to guarantee stable node communication during high-speed production cycles.
• Bulk Material Conveyor Network Maintenance: Installed in trunk end connectors on mineral and grain conveyor DeviceNet networks, the resistor prevents intermittent communication failures caused by long cable runs and high EMI from motor switching equipment.
• Water & Wastewater Instrument Network: The component terminates the DeviceNet backbone for pump and valve instrument clusters. Proper termination ensures reliable transmission of analog values and discrete alarm signals across widely distributed field nodes.

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Key Product Notes

DeviceNet requires exactly two 121Ω terminators, one at each physical end of the trunk cable; extra or missing terminators will cause bus instability. The 1485A-C2 must be wired between the blue and white signal conductors of the DeviceNet cable. This resistor is still available as a standard network accessory, commonly stocked as spare inventory for DeviceNet troubleshooting and network rebuilds. Technicians should verify termination resistance with an ohmmeter while the network power is fully isolated to avoid measurement errors.