Protecting Network Connectors

Myriad industrial network options are only exceeded by the styles and brands of rugged connectors — designed to protect the points linking measurements, logic, actuation, and points in-between and beyond. Robust network connector design can vary by network type (fieldbus, device bus, sensor bus), application, industry (such as electronics, robotics, or nuclear), manufacturer, and standards organizations. Pin arrangements vary for signals and may or may not include power.

Standards include ISA SP-50.3, which incorporates multiple networks. Protocol organizations also specify connector requirements for some networks. Connector types include 9-pin, d-sub (subminiature, D-shell connectors), Micro or Euro (2-6 pins, based on M12 threads), Mini (2-6 pins, 7/8-in. dia barrel with 16 pitch threads), and Pico (3 or 4 pins, M8), as well as M5 and M23, with some designs translating from one to another size. Since wires, rather than cables, transmit some network signals, other wiring hardware and conduit-type connections also can protect.

In general, "rugged" is applicable in industrial environments; some robust industrial connectors are rated with various IEC IP (ingress protection) designations and NEMA-type protection classes. Cabling categories are also referenced for attached connectors, such as CAT 5E and CAT 6—higher numbers have better data throughput and signal-to-noise ratio (TIA-568-B and EN 50173). Electronics connectors include N-Type, TNC, BNC, 7/16 DIN, UHF, Mini-UHF and miniature connectors, SMA, MCX, MMCX, SMB, SSMB, and MC card. There are also reverse polarity N-type, TNC, BNC, SMA, MMCX for Wi-Fi and Broadband. For Ethernet, D-coded M12 are smaller than RJ45 connectors.

A sampling of rugged attributes:

Connections: Most network failures occur at connection points. Connector designs can minimize possibilities of over- or under-tightening, cross threading, or loosening with vibration over time to accommodate industrial applications. Various designs are said to offer proper orientation and snap-on or other quick connections without sacrificing integrity, which is particularly attractive for machine or panel builders, system integrators, or end-users with large projects.

Some quick-connect designs can make T-connections to cables without terminating cable into the connector at three points. Several manufacturers rate the number of possible matings before reliability is threatened. Connectors incorporating seals and gaskets can ease transitions through enclosures, bulkheads, or panels. For high-force applications, lever-type designs can ease connection or removal.

Physical design can mitigate impact, shock, heat, stress, and other abuse. Depending on need, straight or various angled terminations in male or female designs, for single or multiple cables can be offered. Vendors joke that any sturdy network connection has to be strong enough to support a maintenance worker seeking a toehold (not a recommended practice).

Ingress: Exposure to liquids or gases (splashing, pressurization, submersion, and corrosives), spray, dust, and dirt are addressed with appropriate materials, physical designs, locking mechanisms, seals, and o-rings.

Electromagnetic shielding: As with cables, connector design can minimize signal loss due to interference from nearby electronic noise. Designs can provide snap-together construction with visual cues to guide orientation for proper connection and to maintain ground and shielding continuity.