Considerations when selecting a fiber media converter.
By: Allan Evora
A fiber media converter is a piece of hardware in your controls system that converts one communications media (fiber optic) to another (copper).
Why would you want to convert communications media?
- You’re concerned about distance. Typically, there are distance limitations on copper, whether serial or ethernet. Ethernet, for example, can only go about 330 feet (100 meters) without requiring some other type of hardware to extend that distance. Single or multi-mode fiber optic, however, can travel miles.
- You’re concerned about interference. If you’re in a high electrical environment and need isolation from potential communication line noise, such as electromagnetic or radio frequency interference, you might consider a fiber media converter. Unlike copper, fiber optic communications are immune to electrical noise.
- You’ve need to move a lot of data between point A and B. Applications or networks that require a lot of bandwidth are great candidates for fiber media converters. Even though today’s modern copper networks are standardizing on gigabit ethernet, fiber optic cable still has a much higher capacity.
Selecting your fiber media converter
There are a lot more considerations that go into the specification of an industrial fiber media converter, than one being used in commercial. And there are fewer suppliers that specialize in products for industrial fiber media conversion as well.
Some of the brands you might look for include:
- GarrettCom (owned by Belden)
- Ruggedcom by Seimens
There are 5 basic things you need to understand to correctly specify the fiber media converter that will work best for your environment.
Fiber optic type
Is this single mode (SM) or multi-mode (MM)? The diameters of single mode fibers are much smaller than multi-mode. In addition, single mode is used for high bandwidth, long distance applications, whereas multi-mode is used for shorter distances and not as high of a bandwidth.
Is it ethernet or serial, or some specialty network? If it’s serial, is it RS-232, 422, or 485? If it’s a specialty network, does it use Profibus, Devicenet, or Irig-B? Know that most fiber media converters are focused around ethernet and serial. You’ll have a much more limited selection when it comes to specialty networks due to the electrical characteristic differences of the field buses.
Temperature is the most significant parameter when looking at your environment. Companies typically have different classes of product with different temperature ranges. For example, one might have a class of products suited for temperatures of 0’-40’ Celsius, or 0-120’ Fahrenheit. Their second class of products will have a more expanded range, and if they have a third class that will have an even more extreme range. In general, the more extreme your environment, the more expensive the product.
Another environmental consideration to keep in mind when evaluating a fiber media converter is if it will be in a dust-proof and/or rain-proof environment.
Power supply will also drive your selection of media converter. You could have:
- 24VDC (e.g., industrial process control applications)
- 48VDC (e.g., electrical substations)
- 125VDC (e.g., electrical substations)
- 24VAC (e.g., building controls)
One question to ask yourself is, do you want your power supply to be built-in to the media converter hardware, or do you want it to be external? The answer will make a big difference in terms of wire management and panel organization. Typically, if you’re dealing with 48VDC and 125VDC, it will be an internal power supply. 24VDC, 120VAC, and 24AC typically have an external power supply.
As far as mounting options go, you can either panel mount or rackmount. Typical industrial applications call for a panel mounted media converter. However, if you’d like to match it with your rack mounted servers, be aware that not all fiber media converters support rack mount.
Only a select few vendors offer a rack mount chassis with a built-in power supply. GarrettCom and Moxa are two that come to mind who offer modular media converters that plug into a chassis.
If you’re dealing with a rackmount configuration, it’s easy to get a switch or router already rack mountable. Adding fiber optic is as easy as buying an SFP module. In addition to copper ports, you’ll also have one or two SFP-Small Formfactor Plugable (or the older version GBIC- Gigabit Interface Converter) modules. They essentially have fiber optic within them and allow you to save some space and consolidate your conversion to within a switch.
Hopefully these basic considerations when selecting a fiber optic media converter help!
Allan D. Evora is a leading expert in control systems integration and president of Affinity Energy with over 20 years of industry experience working in every capacity of the power automation project life cycle. With a background at Boeing Company and General Electric, Allan made the decision to establish Affinity Energy in 2002. Allan is an alumnus of Syracuse University with a B.S. in Aerospace Engineering, graduate of the NC State Energy Management program, and qualified as a Certified Measurement & Verification Professional (CMVP).
Throughout his career, Allan has demonstrated his passion for providing solutions. In 1990, he developed FIRST (Fast InfraRed Signature Technique), a preliminary design software tool used to rapidly assess rotary craft infrared signatures. In 2008, Allan was the driving force behind the development of Affinity Energy's Utilitrend; a commercially available, cloud-based utility resource trending, tracking, and reporting software.
Allan has been instrumental on large scale integration projects for utilities, universities, airports, financial institutions, medical campus utility plants, and manufacturing corporations, and has worked with SCADA systems since the early ‘90s. A passion for data acquisition, specialty networks, and custom software drives him to incorporate openness, simplicity, and integrity into every design in which he is involved.