AutomatedBuildings.com Article - Wireless Meters: The Real Hotspot

November 2010
Article
AutomatedBuildings.com

Babel Buster: It’s how to connect things to BACnet.
Control Solutions, Inc. – Minnesota
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Wireless Meters
The Real Hotspot

Jim Sinopoli PE, RCDD, LEED AP
Managing Principal,
Smart Buildings LLC

Contributing Editor

With a global focus on energy and our constant dependency on wireless communications it’s not a surprise that when you mix energy meters with wireless you’re bound to get a market “hotspot” for control systems and automation. There was a time when meters weren’t networked and didn’t communicate and a facility technician or the utility’s “Meter Reader” walked to and read the water or electric meter and recorded the numbers on paper or a spreadsheet. The utility industry has long ago moved to Automatic Meter Reading (AMR). However, for some large buildings and commercial or education campuses, manual reading of meters is still the way it’s done.

It’s fair to say that almost every existing building is in need of additional metering to better manage energy performance and could use a simple efficient way of collecting accurate and timely data. Unless you’re determined to hassle with cabling an existing building space or have the time to deal with the difficulties of retrofitting conduit and proper containment for the cable, you’ll need to go wireless to get those meters installed and transmitting data.

Fortunately manufacturers have stepped up and provide us with many wireless meter choices. Wireless communication can be built into the meter or a wireless transceiver can be added as an adjunct to an existing meter. What follows is an overview of the marketplace, the general configuration of the wireless meter networks and the choices you may have for a wireless metering network deployment. Let’s start with a sampling of some of the many offerings in the marketplace:

AIC Wireless has several flavors of one of the most interesting wireless solutions, and is able to handle LonWorks (WLT900), BACnet MSTP/IP (WBT900), Modbus TCP, RS485, and Ethernet (AIC900) protocols. The units are plug-and-play and operate in the 900 MHz frequency. The range of the units can be extended from very short distances up to 40 miles with the use of a 15 dBi antenna (basically a line-of-site repeater). Connector types include an Ethernet RJ-45, USB, and RPSMA. The devices are small (approximately 4.5” X 3.5” X 1.8”) and weigh in around 9 ounces. The transceivers are transparent on the network rather than appearing as a node on the network. The transceiver connects to a hard-wired controller via a base station transceiver, with the controller connected via an Ethernet network back to the system server and an operator administration station.

Veris Industries has a transceiver (H8830) that can handle both Modbus (the dominant protocol used in meters) and pulse devices. Being able to handle pulse devices allows for communication to many existing power, water, gas, steam and BTU meters. The transceivers operate in the 900 Mhz range, are configured in a self-optimizing mesh network and can communicate up to 1,500 feet per hop. There is a companion data acquisition system (H8822) that can handle wired or wireless meters and sensors, and can store interval data.

E-Mon

E-Mon’s wireless metering system is geared towards commercial, industrial and multi-family residential buildings. It consists of several components. This includes 1-phase and 3-phase wireless meters (the Class 2100 and 4100 meters). It also includes a wireless socket meter package, primarily for use in multi-family residential, which allows existing meters to utilize the wireless metering system. E-Mon also uses a self-configuring mesh network. The E-Mon wireless meters are good for about 200 to 2,000 feet within a building depending on line of site and potential interference. The company also has a separate external wireless module that can be used with existing E-Mon power meters and another external module that can handle pulse output which is more geared to gas and water. The system uses a 915 Mhz unlicensed frequency for its wireless. Sitting in-between the wireless transceivers associated with the meters and an IT network is a wireless gateway called the Wireless Data Collector (WDC) which collects data and manages the traffic on the network.

Measurlogic has a wireless transceiver very similar to that of Veris Industries. The differences are that the Veris can be configured for a little more radio output power (150mW) while the Measurlogic can be factory configured to use the 2.4 Ghz radio frequency.

Triacta has a series of meters with wireless built-in to the meter. The 6X03 meter is for low density applications that will be connected to a building automation system. The connectivity is through 802.11 wireless. Interestingly, Triacta provides an Ethernet jack on the meter (in case you can get cabling to the meter) allowing the meter to connect to the IT network. It supports Modbus TCP and BACnet/IP. The 6X03 model can support 2 to 6 meters depending on the phase of the meters. Their 6X12 meters are high density, capable of handling 8 to 24 meters, and having similar wireless connectivity.

System Deployment

The wireless networks can be configured in many ways; mesh networks, point-to-point, fixed, point-to-multipoint and combinations of each. The mesh network may increase reliability, ease system installation and possibly reduce the number of data collectors; the downside for a mesh network may be an increase in network traffic. The ideal solution will be determined by the application, the footprint or size of the network, the number of devices, the potential for interference with the use of unlicensed radio frequencies, the existing building automation systems and the terrain if the installation is exterior to the building.

Also note that wireless communications can be one-way or two-way. In a one-way system, data from the meter is obtained by the system polling the device or the transmitter broadcasting data at pre-determined intervals. Two-way allows for both read and write capabilities, an example being an operator’s workstation being able to “write to” or program the sensor or meter. A mesh network requires two-way communications at the transmitter level.

Generally installation costs for wireless flow or power meter is in the range of $3,500 to $5,000 each. Also, while the focus may be on energy data, the meters bring additional benefits in identifying leakage or tampering.

Assume if you will that the largest problem with managing an existing building is gathering relevant data and transforming data into meaningful actionable information. Wireless metering is an excellent way to fairly quickly install a data gathering system and do so at a reasonable cost. If markets are made by supply and demand, the wireless metering market has both; a variety of products and solutions from a large number of companies and a demand or substantial need in existing buildings.

For more information, write us at info@smart-buildings.com

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