Three Ways to Obtain a Reliable Network

More Than 1s and 0s: Control Systems and Their Networks Now Extend to Field Devices

By Ian Verhappen

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As our control systems become more complex and the workforce transitions to a new generation of workers, what skill sets, especially to solve the nuts and bolts/hardware systems-related issues, are needed to maintain the high levels of network reliability required in this industry? How will you go about developing them?

It should be no surprise that the three most commonly referenced issues regarding how we obtain reliable networks are: 1) design, or getting it right in the first place; 2) installation, meaning proper equipment and construction methods, which are not the same as for analog systems; and 3) training, so the people responsible for providing the design, installation and ongoing maintenance have the skills to perform the work.

SEE ALSO: Designing a Cost Effective, High Performance and Highly Reliable Industrial Ethernet Network

Proper design needs to include the capability to incorporate appropriate diagnostic abilities. Once in use, just like with any other piece of equipment, maintenance practices must include periodic check-ups and baseline measurements to support proactive repairs that ensure uninterrupted network operations. Baseline measurements need to include successful implementation of network maintenance practices that will minimize post-failure repairs, which is when most traditional diagnostics are performed.

Dive Into It
Derrick Stableford, electrical technologist, Associated Engineering, believes that to be effective, you need to be able to "get into the weeds" at times, and adds that, "Probably one of the big skills is the ability to read/interpret an oscilloscope. A scope is the multimeter of networks, and being able to determine noise levels and square wave voltage levels are biggies."

Personal experience has shown it can be difficult to identify each waveform with the associated source of that waveform and be able to associate it with the anomaly, so having a way to trigger the scope on the offending or a particular node is useful.

Merril Harriman, Ethernet systems architect for Industry Business at Schneider Electric, says you also need the right person, an analytical thinker, and he reaffirms the need for the right tools. "There are many simple tools (ping, tracert) that can be employed very easily on a PC, but often are of limited help in an industrial network," Harriman says. "Knowledge of other tools such as SNMP MIB browsers, web pages and native diagnostics capabilities of the protocol in use at the site can be very beneficial as well. Wireshark can be an indispensable tool, but it is surgical in nature, offering a detailed look at a small piece of the network. If you don't know exactly where to look, it could take a long time to find the problem. And for transient problems, it might be hard to catch the event. A good network management tool that will always monitor your entire network can really expedite the process by telling you exactly what the problem is, or by pointing you in the right direction to find the root cause. Such a tool can pay for itself very quickly as the complexity of these networks far outreaches the capabilities of their maintainers."

Jonas Berge, director for applied technology at Emerson Process Management, disagrees somewhat with Stableford on the use of oscilloscopes. "Oscilloscopes might be too difficult for many to use," Berge says. "It has to be set correctly and you need to interpret the waveform. You can of course learn this if you have an instruction with samples of different good and bad waveforms. Therefore, I prefer and recommend use of dedicated testers, which are easier to use and give you pass/fail criteria."

Stableford adds that a strong set of "soft skills" will help you get the support where and when you need it. He lists those as:

  • Be able to "translate geek" to suitable language that can be understood by non-technical staff and managers, without it becoming a weapon of mass sleepiness.
  • Think outside the box, because gremlins certainly will.
  • Maintain a sense of humor, and because this is such a fast moving industry, learn something new every day.

Jonas' Ladder

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