Maintaining connections

There are plenty of issues that cause network headaches, but never assume your electrical subcontractor is familiar with routing and terminating network connector cables, even if they do it all the time.

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ConnectorsBy Mark Lamendola, Contributor

You’ve probably never counted the number of connectors in your network. However, you might be surprised at just how many there are. You might be even more surprised—unpleasantly so—if you’ve been treating signal wire connectors as mere commodity items. Why? Because doing so leads to some of the stealthiest performance and downtime problems a network can experience.

We might not think much about the technology behind each connector, such as which style (see sidebar below) or termination method to use, but all can affect bandwidth, reliability, and total cost of ownership.

The Right Stuff
A sound strategy for preventing connector-related problems begins with using the right connectors. At the very least, these must be industrial-grade rather than consumer-grade.

“Home network devices are meant for conditioned environments,” says David LaBree, CTO of Prime Telecom in Tampa, Fla. “They use inexpensive components to keep prices down. Placing home devices into industrial environments is asking for problems.” Prime Telecom provides network engineering, integration, and maintenance services to municipal and ISP networks.

Manufacturers agree that your first line of defense is to go with industrial devices. Weidmüller is one of many industrial-component suppliers that make connectors suited for harsh environmental conditions, including solvents, fumes, vibration, abrasion, oil exposure, sunlight, cold, crushing forces, corrosive fluids, electrical noise, and extreme heat or cold.

Andre Jordao, Weidmüller’s business development manager for advanced connectivity in North America, says, “One of the biggest problems with Ethernet for industrial applications is that many customers chose to use common, small-office/home-office (SOHO) equipment. The pricing and availability are tempting, but those devices were designed for a clean office environment. These products were never designed to work in harsh environments. The products might work for awhile, but intermittent problems or complete failures are guaranteed. It’s only a matter of time.”

     FIGURE 1: THESE BOOTS ARE MADE FOR WALKING
Protective Boots

Notice the protective boots on these connectors. Your choice of protection devices and methods can affect the reliability of the connection. Expect trade-offs in cost and accessibility.

You also need to provide the proper protection for each connection. (See Figure 1) You must ask what contaminants (e.g., oil, water, or solvents) are present, and to what degree? Do you need to protect from spraying, dripping, immersion, or high concentrations? Your choice of protection devices and methods will affect the reliability of the connection. Expect tradeoffs in cost and accessibility.

Better Methods
Installation matters. “Installation errors can undermine even the best design,” LaBree says. One reason errors occur is complexity. Communication Planning Corp. (CPC), Jacksonville, Fla., is a full-service system integrator serving industrial and commercial markets. Frank Bisbee, CPC’s president, says, “The technology involved in connector hardware can be mind-boggling.” So, if you use outside installers, it’s also good advice to be certain that they know their stuff.

“Never assume your electrical subcontractor is familiar with routing and terminating network cables, even if they do it all the time,” says Chip Schaible, senior engineer at A&E Engineering. “Sit down with them and go through a few example connectors.” Based in Greer, S.C., A&E provides complete industrial automation and information services, from design through integration, to many industries.

A consensus view of the major factors for a good installation includes:

  • Certification of the installers. Look for a relevant BICSI designation.
  • Compliance with the relevant standards, available from BICSI and the IEEE.
  • Post-installation testing with a professional-quality network analyzer (See Figure 2 below).

In addition, “Always go back with a network validation tool, no matter who does the connections,” adds Schaible.

FIGURE 2: A TESTY ATTITUDE     
Equipment Testing
When you appreciate the value of testing and the right equipment, one person can test runs point to point and end to end. Proper testing isn’t expensive, but the cost of inadequate testing can be exorbitant.

LaBree agrees. “The client assumes the design is poor if the network isn’t running optimally,” he adds. “Optimization usually requires each leg or section of the network be tested in its parts, and then tested as a whole. Poor installation will be found in testing.”

The quality of the test also is important. “Those doing the testing need to use the right test equipment and correctly interpret the results,” Bisbee cautions.

There’s a school of thought that says you save money by conducting your first round of testing after the system has been operational for a few months. Bisbee says don’t include him in that school. “It’s more economical to test as part of the installation procedure than it is to haggle later over who’s responsible for that 18-hour downtime incident caused by a faulty connector termination that should have been discovered before system turnover,” he says.

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