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Let’s network

By Chuck Newcombe

December 2012

No, I don’t mean meeting at the local pub to discuss job opportunities, although that might be fun.

It seems we all carry cell phones these days, and between email, text messaging, and Facebook, just to name a few, we have plenty of opportunities to participate in social networks. These same phones have high bandwidth, wide area network (WAN) communication capabilities, using WiFi (IEEE 802.11) and wireless personal area network (WPAN) BlueTooth (IEEE 802.15.1), in addition to the cell phone network.

My column this month discusses the state of the very low bandwidth networks that control our home lighting and security, and similar completely portable networks operating for months or years on small internal batteries.

X10

One of the earliest home network standards was X10, first described in 1975 by Pico Electronics of Scotland. I’ve had light switches and various X10 controller/timers in use in my home since the 1980s.

I suppose you could call this a star network, because communication takes place using carrier signals transmitted on the electrical network wiring of my home, from one receptacle or switch to another via the electrical service panel acting as the hub.

X10 wireless remote control products require batteries, of course, but the X10 switching devices are powered directly from the household electrical service.

Z-Wave

A more recent home network development is Z-Wave, a proprietary wireless communications system similar in application to X10. The major difference is that all communications are wireless, operating in the sub-gigahertz 900 MHz range. Z-Wave can be described as a mesh network, where modules can act as repeaters, to pass a signal through to an otherwise out-of-range module.

I’ve actually installed a network of Z-Wave switches in conference rooms to allow zone control of lighting using wireless remote controls. Like X10, Z-Wave also has switch modules powered by the electrical system to which they are connected.

ZigBee

The ZigBee Alliance group has developed a specification for high-level layers of a low-power communications mesh network. I first discovered their activity in about 2001 while I was still working for Fluke. At the same time, the IEEE was developing a standard for low power radios to work in such systems. The IEEE 802.15.4 standard for low power radios, operating in the 2.4 GHz range, was first published in 2003. It would be 2005 before the first ZigBee Alliance specification was published.

My campaign for Fluke low bandwidth wireless products

I saw possibilities for these developing technologies in future Fluke products, and began selling the idea internally until my retirement in 2005. But, as often happened in my career, my enthusiasm for such leading technologies was dampened somewhat by Fluke’s well justified conservatism when it comes to the products it offers to its loyal customers. We had to see stability and reliability in the components to be used in our products.

Fluke’s first products using IEEE 802.15.4 radios

Imagine my delight when I discovered that Fluke was developing the Fluke 233 Digital Multimeter (DMM), and soon thereafter, the Fluke 381 Clamp Meter. Both of these products feature a removable display unit that can be used for viewing remotely, away from the site of the actual measurement. The wireless communications in these units used the low power GHz radios based on the IEEE standard that had excited me years before.

Now, finally, the products I had in mind 10 years ago

A few weeks ago I was asked to evaluate a family of Fluke products that can be used in a low-power wireless star network to perform tasks such as remote logging and measurement.

t3000 Wireless K-type Thermometer front panel

A close-up of the t3000 Wireless K-type Thermometer front panel is shown here.

This new family of products is known as Fluke CNX 3000 Series. The models I worked with are small stand-alone single function meters, complete with display, which can measure temperature, ac voltage, and ac current. Two buttons on the front panels of these instruments were exciting to me.

The unit, of course, has the usual on/off and backlight buttons, and, in the case of the thermometer, a button to select temperature display in either ˚F or ˚C. The really exciting thing with this and the other products is the presence of the other two buttons - one for wireless communications, the other to control a data logging feature.

I was able to log temperature readings to memory in the meter, and then download the results to my laptop using a wireless USB “stick” and the PC software necessary to enable laptop communications with the new devices.

Logged data is stored in text files compatible with popular PC spreadsheet and processing programs. And, your computer can be connected to as many as ten remote devices at a time, including the wireless DMM, for live readings.

There is one more new product in the family - a DMM that is equivalent to the model 179, but with one major exception. This unit has the ability to communicate with the single function modules to display live readings from up to three of them on screen along with the active DMM measurement.

An HVAC technician was just at my house to check out my furnace before winter sets in. He happened to spot these new products and left here trying to figure out how he was going to justify these additions to his Fluke arsenal to his wife. I wished him luck.

My dreams of 2001 are finally coming true.

Learn more
The Fluke CNX 3000 Series »