Wireless Base Stations

In radio communications, a base station is a wireless communications station installed at a fixed location and used to communicate as part of a push-to-talk two-way radio system, or a wireless telephone system such as cellular CDMA or GSM cell site. In professional two-way radio systems, a base station is used to maintain contact with a dispatch fleet of hand-held or mobile radios or to activate one-way paging receivers. The base station is one end of a communications link. The other end is a movable vehicle-mounted radio or walkie-talkie.

A wireless telephone base station communicates with a mobile or hand-held phone. As an example, in a wireless telephone system, the signals from one or more mobile telephones in an area are received at a nearby base station, which then connects the call to the land-line network. Other equipment is involved depending on the system architecture. Mobile telephone provider networks, such as European GSM networks, may involve carrier, microwave radio, and switching facilities to connect the call. In the case of a portable phone such as a US cordless phone, the connection is directly connected to a wired land line.

The base station is the core of RF wireless installations and it’s where you make the connections for your cables, antennas, transmitters and receivers. This is where most problems can occur that affect performance through component failures, wireless interference or incorrect installation or maintenance. The result can be unacceptable and costly downtime for your networks, and time-consuming work to fix the problem by your field techs.

Base Transceiver Station

The base transceiver station, or BTS, contains the equipment for transmitting and receiving radio signals (transceivers), antennas, and equipment for encrypting and decrypting communications with the base station controller (BSC). Typically a BTS for anything other than a picocell will have several transceivers (TRXs) which allow it to serve several different frequencies and different sectors of the cell. A BTS is controlled by a parent BSC via the base station control function (BCF).The BCF is implemented as a discrete unit or even incorporated in a TRX in compact base stations. The BCF provides an operations and maintenance (O&M) connection to the network management system (NMS), and manages operational states of each TRX, as well as software handling and alarm collection. The BTSs are equipped with radios that are able to modulate layer 1 of interface Um; for GSM 2G+ the modulation type is GMSK, while for EDGE-enabled networks it is GMSK and 8-PSK. Frequency hopping is often used to increase overall BTS performance; this involves the rapid switching of voice traffic between TRXs in a sector. A hopping sequence is followed by the TRXs and handsets using the sector. Several hopping sequences are available, and the sequence in use for a particular cell is continually broadcast by that cell so that it is known to the handsets.

Due to aesthetics issues in many communities base stations are now being disguised as trees so they blend into their environment.

Base Station Industrial Resources

Anritsu Master Users Group
The Master Users Group is a Community dedicated to providing training, technical support, networking opportunities and links to Site Master, Spectrum Master, Cell Master, UMTS Master, and BTS Master product development teams, along with other valuable information for Master Users and Certified Master Users. The Master Users Group is uniquely positioned to deliver technical, educational, and career resources to our members. Master Users have the strength in numbers to develop and deliver significant benefits to today’s telecom service providers, tower companies, and wireless professionals. The Master Users Group offers users an opportunity to exchange ideas, discuss problems, explore solutions and provide interaction with Anritsu executives, developers and application engineers. Members receive a quarterly newsletter and get email notifications of new software releases. Membership is free and the only qualification is a genuine interest in the effective use of Anritsu Site Master, Spectrum Master, Cell Master, UMTS Master, and BTS Master instruments.  www.us.anritsu.com/masters

3rd Generation Partnership Project (3GPP)
3GPP was created in December 1998 by the signing of the “The 3rd Generation Partnership Project Agreement”. Its original scope was to produce Technical Specifications and Technical Reports for a 3G Mobile System based on evolved GSM core networks and the radio access technologies that they support (i.e., Universal Terrestrial Radio Access (UTRA) both Frequency Division Duplex (FDD) and Time Division Duplex (TDD) modes). The scope was subsequently amended to include the maintenance and development of the Global System for Mobile communication (GSM) Technical Specifications and Technical Reports including evolved radio access technologies (e.g. General Packet Radio Service (GPRS) and Enhanced Data rates for GSM Evolution (EDGE)).  www.3gpp.org

Third Generation Partnership Project 2 (3GPP2)
3GPP2 is a collaborative third generation (3G) telecommunications specifications-setting project, comprising North American and Asian interests developing global specifications for ANSI/TIA/EIA-41 Cellular Radio telecommunication Intersystem Operations network evolution to 3G and global specifications for the radio transmission technologies (RTTs) supported by ANSI/TIA/EIA-41.  3GPP2 was born out of the International Telecommunication Union’s (ITU) International Mobile Telecommunications “IMT-2000” initiative, covering high speed, broadband, and Internet Protocol (IP)-based mobile systems featuring network-to-network interconnection, feature/service transparency, global roaming and seamless services independent of location. IMT-2000 is intended to bring high-quality mobile multimedia telecommunications to a worldwide mass market by achieving the goals of increasing the speed and ease of wireless communications, responding to the problems faced by the increased demand to pass data via telecommunications, and providing “anytime, anywhere” services. www.3gpp2.org

3G Americas
3G Americas unites mobile operators and manufacturers in the Americas to provide a single voice to represent the GSM family of wireless technologies — GSM, GPRS, EDGE, and UMTS/HSDPA. 3G Americas is committed to working with regulatory bodies, technical standards bodies and other global wireless organizations in order to promote truly seamless interoperability and convergence. These relationships include Market Representation Partner for 3GPP (Third Generation Partnership Project), membership in CITEL (Inter-American Telecommunications Commission), collaborative working agreements with the GSM Association, UMTS Forum, and ASETA (Association of Telecommunications Enterprises of the Andean Community). www.3gamericas.org

CTIA-The Wireless Association
CTIA-The Wireless Association, is an international nonprofit membership organization founded in 1984, representing all sectors of wireless communications: cellular, personal communication services and enhanced specialized mobile radio. The organization represents service providers, manufacturers, wireless data and internet companies, as well as other contributors to the wireless universe. CTIA advocates on their behalf before the Executive Branch, the Federal Communications Commission, Congress, and state regulatory and legislative bodies. CTIA also coordinates the industry’s voluntary efforts to bring consumers a wide variety of choices and information regarding their wireless service, and supports important industry initiatives such as Wireless AMBER Alerts, and the “When it comes to Wireless, Safety is Your Call” safe driving public service announcement campaign. www.ctia.org

GSM Association (GSMA)
Founded in 1987, GSMA is a global trade association representing more than 750 GSM mobile phone operators across 219 countries and territories of the world. In addition, more than 210 (numbers taken from the online brochure) manufacturers and suppliers support the Association’s initiatives as associate members. The primary goals of the GSMA are to ensure mobile phones and wireless services work globally and are easily accessible, enhancing their value to individual customers and national economies, while creating new business opportunities for operators and their suppliers. The Association’s members represent more than 3 billion GSM and 3GSM connections — over 86% of the world’s mobile phone connections. www.gsmworld.com

Posted in Technology, Test & Measurement Tech |

Test Equipment Connection Opens New Affiliate in Singapore

Lake Mary, FL USA - Test Equipment Connection Opens New Affiliate in Singapore

Test Equipment Connection Corporation announced today that Test Equipment Connection Pte. Ltd., based in Singapore, is now operational.

“Since we established our Hong Kong operations in September 2007, our transactional volume has expanded significantly in Southeast Asia,” said President John Bahng. “Our Singapore facility will enable the continued growth we are seeing in sales and purchases of second hand test equipment in Singapore, Malaysia, Indonesia, Thailand, Viet Nam and the Philippines. Expanding into Singapore compliments our Hong Kong office and furthers our ability to add additional staff and better respond to our local customers’ test equipment needs.”

About Test Equipment Connection Corporation

Test Equipment Connection Corporation, Test Equipment Connection Pte. Ltd., and TE Connection Asia Limited are industry-leading suppliers of new, refurbished and second-hand electronic test and measurement (”T&M”) equipment. The companies sell, buy, lease, rent, trade, repair and calibrate over 315 manufacturers including Agilent, Tektronix, Anritsu, Rohde & Schwarz, Advantest, Megger, LeCroy, Chroma and Fluke, with thousands of products available. The companies are a single source supplier with in-house calibration laboratories assuring that customers receive only the highest quality T&M equipment and support. Test Equipment Connection Corporation has over 250,000 customers, a 45,000 square foot warehouse and repair facility in the US, and 16 years of profitability and financial strength.

Visit www.TestEquipmentConnection.com

or

email Info@Teconnectionasia.com for more information.

Test Equipment Connection Pte. Ltd.
6 Battery Road
#31-00 Standard Chartered Bank Building
Singapore 049909  Telephone: 65-6320-8596

TE Connection Asia, Ltd.
Unit 13, 16 / FL Fotan Industrial Centre
26-28 Au Pui Wan Street
Fotan Shatin N.T.    Hong Kong: 852-2690-1360 China: 86 136-3217-2095

###

Test Equipment Connection Corporation

30 Skyline Drive
Lake Mary, FL 32746 USA   (800) 615-8378 x 141

Press Release Contact Information:
Phil Vogel  business@testequipmentconnection.com

Posted in Press Releases |

Test Equipment Connection Signs Distribution Agreement with Chroma Systems Solutions, Inc.

Lake Mary, FL USA - Chroma Systems Solutions,  Inc., internationally known for it’s AC and DC Loads,  AC Power Sources and power supply testing equipment, has today joined  forces with Test Equipment Connection through a worldwide distribution  agreement.

Test Equipment Connection, the global single source supplier of general purpose electronic test equipment, will distribute Chroma power products including AC and DC loads, programmable AC Power sources, DC power supplies and digital multi / power meters. “Chroma is a world leader in power test instruments and systems,” commented Mike Novello President and COO of Test Equipment Connection. “Our customers are upgrading to new Chroma AC and DC power supplies after learning about the Chroma brand. Chroma delivers precise high power testing at a great price.”

About Test Equipment Connection Corporation:

Test Equipment Connection Corporation and TE Connection Asia Limited are industry-leading suppliers of new, refurbished and second-hand electronic test and measurement (”T&M”) equipment. They sell, rent, lease, buy, trade, repair and calibrate over 315 manufacturers with thousands of products available new and refurbished. The companies are a single source supplier with in-house calibration laboratories assuring that customers receive only the highest quality T&M equipment and support. Test Equipment Connection Corporation has over 250,000 customers, a 45,000 square foot warehouse and repair facility in the US, and 16 years of profitability and financial strength. Visit www.TestEquipmentConnection.com for more information or call (800) 615-8378 or (407) 804-1299.

About Chroma Systems Solutions:

Chroma is the largest worldwide provider of power testing instruments and systems including programmable AC Power Sources and DC Power Supplies, AC Loads and DC Electronic Loads, Digital Power Meters, Multi-Meters, and Automated Power Supply Testing Systems.  Chroma’s programmable power supplies, electronic loads, measurement instruments and automated testing systems provide solutions for applications in aerospace, defense, military, automotive, medical, battery, solar, marine, and regulatory testing.  Customized systems and instrumentation for power supply test and characterization include architecture and platforms built to fit diverse bench-top, R&D, design verification and automated test system technical requirements and specifications. Applications include testing of batteries and battery chargers, grid inverters, solar panels/arrays, DC-DC & off-line power supplies, fuel cells, photovoltaic arrays and many other related products. With offices and manufacturing facilities located worldwide, Chroma is renowned for it’s commitment to excellence in product, service, and innovation. Chroma Systems Solutions, Inc. is located in Lake Forest, CA. For more company and product information visit their website at www.ChromaUSA.com or call (949) 600-6400.

Posted in Press Releases |

World Standards Day 2009

What is World Standards Day?

World Standards Day began as a celebration of the birth of the International Organization for Standardization (ISO www.iso.org), which held its first meeting in London on October 14, 1946. From an initial roster of 25 countries, ISO (based in Geneva, Switzerland) now has 123 member nations and has evolved into the global clearinghouse for all standards activities. ISO’s U.S. representative, the American National Standards Institute (ANSI www.ansi.org), is one of the founding organizations of World Standards Day. Today, World Standards Day is sponsored annually by ISO; the International Electrotechnical Commission (IEC www.iec.ch), which develops international standards for the electrical and electronics industries; and the International Telecommunications Union (ITU www.itu.int), an international organization  responsible for the coordination, development, regulation, and  standardization of telecommunications standards.

The goal of World Standards Day is to raise awareness of the importance of global standardization to the world economy and to promote its role in helping meet the needs of business, industry, government, and consumers worldwide. The international event pays tribute to the thousands of volunteers around the world who participate in standardization activities. Since its initial celebration in 1970, member countries commemorate World Standards Day by organizing special gatherings and events, ranging from conferences, exhibitions, and seminars to film shows, TV and radio interviews, and full “standards weeks” around mid October.

How Does the U.S. Mark This Day?

Each October in Washington, DC, members of the U.S. standardization  community gather with other leaders in business, industry and government  for a U.S. World Standards Day exhibit, reception and dinner gala. During the dinner ceremony the Ronald Brown Standards Leadership Award is presented to an individual who has demonstrated leadership in promoting the  important role of standardization in eliminating global barriers to trade.  Awards are also presented to the winners of the World Standards Day Paper  Competition, which is designed to raise awareness of the importance of  standards, as well as present various perspectives on national and international standards and conformity assessment issues.

Who Sponsors World Standards Day in the U.S.?

In the U.S., World Standards Day is a joint effort between the private and public sector. This year’s World Standards Day events were coordinated and funded by the World Standards Day Committee, consisting of representatives from more than 25 major companies, professional and technical societies, trade associations, standards developing organizations and government agencies. The co-chairs of the World Standards Day Committee are the American National Standards Institute (ANSI) and the National Institute of Standards and Technology (NIST).

Why is U.S. Recognition of World Standards Day Important?

World Standards Day presents the American business community with an  opportunity to demonstrate its commitment to the important role standards  play in increasing U.S. competitiveness. In today’s changing economy,  industry, government, standards developing organizations, and other groups need to work together to ensure that U.S. products and services are accepted  in the global marketplace, thereby enhancing U.S. leadership abroad. World Standards Day provides the U.S. with the forum to build on such relationships.

What is the American National Standards Institute (ANSI)?

ANSI is a private nonprofit membership organization that coordinates the U.S. voluntary standards system, bringing together interests from the private and public sectors to develop voluntary standards for a wide array of U.S. industries. The Institute’s membership includes approximately 1,100 national and international companies, government agencies, and professional, technical, trade, labor, and consumer organizations. ANSI is the official U.S. member body to the world’s leading standards bodies – the ISO and the IEC via the U.S. National Committee. www.ansi.org

What is the National institute of Standards and Technology (NIST)?

NIST is a non-regulatory agency in the U.S. Department of Commerce’s Technology Administration. Formerly known as the National Bureau of Standards, NIST promotes economic growth by working with industry to develop and apply technology, measurement, and standards.  www.nist.gov

(source www.ansi.org)

Posted in Technology |

Electronic DC Loads Simulate Non-Linear Behavior

Chroma’s 63600 Series DC Electronic Loads are designed for testing multi-output AC/DC power supplies, DC/DC converters, chargers, batteries, adapters, and power electronic components. Excellent for research, development, production, and incoming inspection applications. The 63600’s state of the art design uses DSP technology to simulate non-linear loads using an unique CZ operation mode allowing realistic loading behavior. The 63600 series can draw its full rated current to almost zero volts. This unique feature guarantees the best loading performance for fuel cells and modern Point-of-Load devices.

Posted in Product News, Technology |

Zero-Ohm Load

In Search of the Zero-Ohm Load

High-wattage resistors often are used as test loads for power transformers. Resistors don’t introduce phase shifts, and it’s easy to check that a transformer’s voltage regulation remains within spec at different rms currents. The effect of various primary tap and secondary loading combinations also can be measured. On the other hand, actual loads don’t always have a constant resistance (CR) characteristic.

Many switching power supplies present a constant power (CP) load to the AC input. DC power supply outputs are intended to provide a constant voltage (CV) or constant current (CC) depending on the mode selected. To simulate anything other than simple CR, you need an electronic load.

Both AC and DC electronic loads are commercially available with DC loads being more prevalent. Either type can emulate a short circuit as well as the CC, CV, CR, and CP modes of operation. According to Adrian Butoi, western regional manager at NH Research, AC loads are used for test applications that require linear or nonlinear AC loading with power and crest-factor control. In addition to the five basic modes of operation, the company’s Model 4600 AC Load also provides unity power-factor loading and a complex nonlinear waveform mode.

Built-in measurements include frequency, voltage, peak voltage, current, peak current, crest factor, apparent power, true power, peak power, reactive power, power factor, and resistance. DC load measurements compose a subset of this list that is not related to reactance.

Cliff Nazelli, the managing director of marketing and sales at PPM Instruments, described a couple of typical applications. In one example, vehicle electrical-system power-distribution module testing must simulate various load conditions. While the module’s durability and temperature rise are monitored, the load current is switched on and off. In another test, fuel-cell impedance is measured by modulating the DC load current. The impedance is determined from the current and voltage amplitudes and their phase relationship.

Isolation also is critical in many cases, especially those that involve off-ground differential voltage sources. Multitap battery load testing is an application that requires this capability.

DC Load Basics

Typically, MOSFETs are used as the dissipating devices in a DC load. These semiconductors have ON resistance much less than 100 mΩ, and several are operated in parallel to achieve the needed power rating. Of course, paralleling devices also reduces the resistance the load presents.

ON resistance is higher for high-voltage MOSFETS than for low-voltage devices, so DC loads rated for 500 V generally will have higher resistance than 50-V loads even if the same number of MOSFETS is used. Figure 1 shows this effect for a 5-kW PPM 600-V load (dark green curve) compared to a 5-kW 60-V load (red curve). The initial slope of the PPM Modular Electronic Load (Mel) 5000-200-600 is 30 mΩ compared to the 1-mΩ resistance of the Mel 5000-600-60 even though there is only a 3:1 ratio relating their maximum currents. The resistances of the lower wattage Chroma loads range from 5 mΩ to 25 mΩ.

Figure 1. Safe Operating Areas for Various DC Loads
Source: Chroma Systems Solutions and PPM Instruments

All electronic loads have a safe operating area (SOA) limited by voltage, current, and power. These areas are indicated in Figure 1 for the PPM Mel 5000-600-60. As the input current increases, the voltage across the load also increases because of the load’s finite resistance. At the maximum current, higher voltages can be supported but only to the maximum voltage and power ratings.

On a graph with linear X- and Y-axis scaling, the maximum power curve is a hyperbola. The load voltage can continue to increase to the maximum voltage limit as long as the current is low enough that the maximum power limit isn’t exceeded. As the figure shows, the SOAs of loads having the same power limit are bounded by the same hyperbolic curve although it may be intersected at different places by the voltage and current limits.

It’s also important to note the lack of standardization regarding load specification in datasheets. The NH Research Model 4750 DC Load and PPM Mel Series show the SOA on a graph with voltage plotted vertically and current horizontally on a log-log grid. Chroma’s 63600 Series datasheet plots this information with the same axes but on a linear grid.

Several manufacturers’ graphs showing low-voltage characteristics generally have linear grids with current plotted vertically and voltage horizontally. Of course, depending on the DUT, current or voltage could be the independent variable, so it really doesn’t matter how the graphs are drawn as long as you understand what they mean.

Finally, model numbers may include power, voltage, and current limits but not always in the same order. PPM’s Mel Series lists power, current, and voltage: Model 5000-200-600 is a 5-kW load with 200-A and 600-V maximum limits. Chroma’s Model 63630-80-60 is a 300-W unit with 80 V and 60-A capabilities.

DC Load Selection

You must choose a load with an SOA sufficient to handle the maximum current, voltage, and power expected from the DUT. The actual combination of current and voltage can lie anywhere within the SOA. Nevertheless, the trend in semiconductors is toward low voltage and high current so supporting this combination often is a major consideration.

Jim Dougherty, senior engineer at Chroma Systems Solutions, explained, “Up to a maximum current limit, a DC load presents a constant minimum resistance. For example, if a load can support a 10-A current and has a 10-mΩ resistance, the DUT output voltage must be at least 100 mV even if the connections and wiring were perfect. Taking into account the finite resistance of the connections and wiring further increases the minimum DUT output voltage required for the load to sink the full current. Of course, the load can be programmed to represent a higher resistance but you cannot get less than the minimum.

“Suppose you have designed and characterized your DUT interconnect and cable resistance and found that RSeries = 2 mΩ. Further, assume you need to support 0.5 V @ 60 A. To do this,” he continued, “the DC load must represent a resistance RLoad <(0.5/60)-0.002 or RLoad <~6 mΩ. The sloping lines in Figure 2 show the resistance associated with three models of Chroma 63600 Series Loads and correspond to the area circled in Figure 1. As expected, the higher the output current rating, the lower the resistance. And, loads can be operated in parallel to achieve higher current capacity as well as lower resistance.”

Figure 2. Low-Voltage Resistance Characteristics of DC Loads
Courtesy of Chroma Systems Solutions

Zero-Volt Operation
What if you need to sink the full rated current but the voltage drop associated with the load resistance and wiring is large compared to the DUT output voltage? Adding a boost supply in series with the load effectively increases the DUT output voltage and makes possible even zero-volt full current loading.

However, Mr. Dougherty cautioned, “Boost supplies should be considered only as a last resort. The effective power of the load that otherwise would be available to the DUT is reduced; you no longer can perform transient tests; noise from the supply affects ripple and noise measurements; and complexity and cost are increased.”

Commenting on his company’s true zero-volt PLZ-4WA Series of DC loads, Takuya Takeda, vice president of Kikusui America, said, “The PLZ-4WA employs a bias supply installed directly in the electronic load. It supports true zero-volt operation by stepping up the input voltage and applying a load voltage adequate to allow the internal current source to operate correctly.

“A switched-mode power supply is small enough to fit inside the load,” he continued. “Typically, a switched-mode supply can create noise issues, but that is not the case with this bias supply. It has been designed using zero-volt switching technology and other special techniques to reduce noise.”

An extensive feature set has developed around the basic DC load function to address a wide range of applications. Four-wire Kelvin connections ensure that the DUT terminal voltage is used in power calculations, not the load voltage that is reduced by wiring and connection IR drops. Also, because many tests require switching the load on and off to stimulate DUT transient response, this aspect of DC load design has become very sophisticated.

Transient Response
A DC load’s internal wiring and terminations must present a low impedance, not just a low resistance. Mr. Nazelli explained that PPM uses a heavy-duty laminated copper bus structure internally in conjunction with a proprietary FET circuit board layout to ensure the lowest possible impedance. In particular, the laminated copper bus minimizes the impedance increase caused by skin effect that otherwise would occur at high frequencies.

The depth at which AC current density has been reduced to 37% of its value at the conductor surface is given by

where: δ = skin effect depth
ρ = conductor resistivity
ω = 2πf
µ = conductor absolute magnetic permeability

For a copper conductor, skin depth varies from more than 8 mm at 60 Hz to only 66 µm at 1 MHz. Engineers have used Litz wire for many years to minimize the resistance increase caused by skin effect. Litz wire is stranded, but each strand also is insulated. A laminated bus achieves a similar result in a form that may be more easily manufactured and terminated, especially for high current levels.

The PPM Mel units are specified with a 15-µs to 20-ms rise time, selectable in 36 discrete steps, and a DC to 10-kHz frequency response. A 600-A load has a maximum slew rate of 600/15 or 40 A/µs. When loads are connected in parallel, the slew rates add. On the other hand, the highest practical slew rate is limited by the inductance of the wiring needed to connect the loads in parallel.

Kikusui’s Model PLZ1004W is a 1-kW load with a maximum current rating of 200 A and a slew rate of 16 A/µs. For the PLZ-4W Series, the slew rate is variable over a 100:1 speed ratio and guaranteed to be accurate to within 10% for current within 2% to 100% of rated value. This series also supports frequency range selection.

According to Kikusui’s Mr. Takeda, “Dynamic response only is required for transient response tests of power supplies. A wide bandwidth isn’t necessary for static tests such as load variation tests and foldback characteristic tests. Excess bandwidth affects load stability so the PLZ-4W/4WA load includes selectable bandwidth, and it can be optimized to match the kind of test and test condition.”

NH Research’s Mr. Butoi explained that because the load manufacturer cannot control DUT and cable inductance, the most straightforward solution to mitigate voltage spikes, ringing, and oscillation is to allow load-current slew-rate programmability. Usually, slowing this slew rate eliminates the problems.

PPM provides two types of filtering as discussed by Mr. Nazelli, “The architecture of the Mel employs a control board with programmable loop response to vary the control-loop speed where you need to adjust rise/fall times for pulse tests and stimulus/response testing. This is one type of filtering. Separately, filtering is used on the FET circuit board assemblies to control the feedback loop response of the power-dissipating devices. The operator can adjust the loops to shape the response either to further control rise/fall times or eliminate oscillations induced from external reactive components.”

Power to the Load

Regardless of the other characteristics a DC load may have, it must dissipate power-sometimes a lot of power. The products in PPM’s Mel Series can handle 1 kW to 5 kW, and master-slave configurations up to 80 kW are standard. Eight models in NH Research’s 4700 Series range in capacity from 1 kW to 36 kW. Chroma’s Series 63200 High Power DC Loads are available in sizes from 2.6 kW to 15.6 kW. These three load series are air-cooled.

Most manufacturers of heavy-duty loads support paralleling for higher power handling. Loads feature individual device protection against over-temperature, over-voltage, and over-current conditions and further ensure performance through active current balancing. For larger power ratings, master-slave systems usually are rack mounted and up to 6 ft high.

One alternative to a big air-cooled unit is a water-cooled unit. AMREL’s PLW Series handles up to 250 kW, and several versions of the 36-kW model are available in a 4U-high x 27.5″ deep rack-mount size. As a comparison, a 5-kW AMREL Series PLA Air-Cooled Load is approximately the same size.

Another solution appropriate for high-power applications is Kikusui’s Model PLZ6000R Regenerative DC Electronic Load. The basic unit acts as a 6-kW load although only about 15% of this is dissipated. The rest of the power is regenerated as a synchronous AC current fed back into the AC mains. Up to five units can be combined in a master-slave system to provide a 30-kW capacity.

Several ranges of benchtop DC loads also are available with ratings to a few hundred watts. Three models from Chroma’s 63600 Series are shown in Figures 1 and 2. B&K Precision’s 150-W Model 8540 handles up to 60 V and 30 A in the CC, CR, and CV modes with current, voltage, and power measurements presented on an integral display. Model 8510 has a 600-W capacity with 120-V and 120-A limits. It, too, provides an integral display and includes a CP mode as well as battery test capability.

Kikusui’s PLZ-4W Series features 165-W, 300-W, 660-W, and 1-kW models. In addition to the basic products, the 165-WA and 660-WA models are available with a built-in bias supply and support true zero-volt operation.

The 300-W Model LD300 DC Load manufactured by Thurlby Thandar Instruments and available in the United States from Saelig has 80-V and 80-A maximum ratings. It supports the CC, CV, CR, and CP modes and provides a transient generator, a variable slew rate, soft start, and a current monitor output.

Controlling the Power
In addition to a load’s fundamental capabilities, the extra features it offers can be important depending on the types of tests you need to run. Kikusui’s PLZ-4W Series includes soft start, a variable slew rate, a switching function, a preset memory function, 100 setup memories, and a sequence function.

B&K Precision’s 8500 Series Loads also support battery testing by measuring total battery discharge in amp-hours. Jeremy Lo, an application engineer at the company, said, “Software is available to control the load for this test. It plots battery discharge curves in real time as well as gives you the option to export raw data in text or Excel format for further analysis. The software also can be used to monitor and plot power, voltage, and current levels at the load inputs.”

In NH Research’s Model 4700 DC Electronic Load, an auto mode provides glitchless switching among the CR, CC, CV, and CP limits. Further, you can programmatically control the mode of operation and its duration via a 100-step customizable macro with 10-µs timing resolution.

PPM’s Mel Loads have several means of control. RS-422 and USB 2.0 ports are standard with both GPIB and Ethernet optionally available. You can log into a load’s IP address to perform remote control and diagnostics. According to Mr. Nazelli, “This also enables PPM to send feature improvements without hardware intervention and without requiring you to return units to PPM. In addition, you can add modules in the field to upgrade a load. The load automatically reconfigures itself to its new capabilities.”

Chroma’s Model 63472 High Slew Rate DC Load incorporates Intel’s power test tool (PTT), which can simulate microprocessor load changes of up to 150 A at a 1,000-A/µs slew rate. Because the PTT is small enough to fit into a microprocessor socket, it cannot dissipate the required power without significantly changing its temperature and operating characteristics. The 63472 provides measurement hardware and over-current and over-voltage protection as well as the automatic calibration required to ensure test-result accuracy.

Unless you use a device such as the PTT, there’s no way to connect a high slew-rate load that will not introduce significant errors. The PTT mimics the load presented by a microprocessor, which may have 100 or more power and ground pins. The slew rate at each pin is only a few amps/µs, and most of the transient current is provided by local capacitors. With the PTT, you are testing the capability of the power supply in combination with local capacitors to cope with the overall 150-A changes and 1,000-A/µs slew rate.

Summary

Many models of DC electronic loads are available, some with very specialized capabilities. Determining the load that will best fit your test requirements starts with a list of the specifications you must have. Power dissipation, maximum current and voltage, and the minimum resistance the load presents are key to most applications. So, too, are the modes in which you will operate the load and how it changes from one to another.

(Source Tom Lecklider -  Evaluation Engineering http://www.evaluationengineering.com/features/2009_september/0909_electronic.aspx )

Posted in Applications, Product News, Technology |

Megger Insulation Testers

Megger’s MIT400 Series of Hand-Held 1 kV Insulation Testers

These 1 kV units were designed based on Megger’s extensive knowledge of insulation testing (100+ years of experience) and significant feedback from actual end users.

The MIT400 units include:

Megger’s patented digital/analog display with real-time pointer movement. Other manufacturer’s units do not offer a true analog arc display with pointer travel. Some offer only a digital readout while others offer an analog bargraph that does not provide any of the information gained from pointer travel.

Industry best (by far) measurement sensitivity, allowing users to identify potential problems early before they become bigger problems. The MIT400 Series’ measurement sensitivity (up to 200 GΩ) dwarfs anything found on comparable units.

CAT IV, 600 V safety rating on BOTH insulation and continuity  measurement ranges. Some competitive units claim a CAT IV, 600 V safety rating, but have no rating on the continuity measurement.

Industry best IP54 (ingress protection) rating (protection against splashing water from any direction). Some competitive units have an IP rating of IP40, which means they are not protected against liquid ingress at all.

How important is the electrical equipment you intend to test?

The MIT400 Series offers the highest measurement range available, which will allow you to identify problems early. Additionally, the real-time analog arc provides an experienced user key additional information.

In what types of environments are you testing?

The MIT400 Series has the highest IP rating of the available instruments. They can be used effectively in the harshest conditions.

How important is safety?

In addition to being CAT IV, 600V rated, the MIT400 Series units (like all Megger insulation testers) are designed with Megger’s Intelligent Safety System, which includes specific protection circuitry to ensure that, in the case of incorrect connection or accidental connection to unsuitable circuits, no damage will occur to the instrument, and the operator is fully protected.

Do you want to purchase a true insulation tester?

All Megger models are based on an insulation tester “footprint” and are designed for insulation testing applications. Some competitive units are multimeters first with insulation testing capability added second.

Application Guru, Jeff Jowett of Megger answers the following question.

Q:  What is the significance of line powered or battery powered?

A: Battery power is safe and more convenient. But in the “old days,” batteries developed a bad reputation for unreliability and rapid drain. Modern conservation techniques in well-designed equipment have eliminated these shortcomings, making battery-powered units more portable and, of course, not dependent on site power, hence more amenable to field work and construction environments. They also provide a much better regulated power source, free from the effects of transients and other line disturbances. Furthermore, as a self-contained power source, they can be designed so as to be well within safety parameters, which is difficult to guarantee with line power that is connected to the North American grid! A common misconception is that line power somehow provides a “better” (i.e. more robust) test. The only thing that all that extra power might get you is arc flash! It does NOT provide a more reliable test.

The only disadvantage that batteries do have is that they eventually go dead. This leaves battery power open to “human error.” Dual-powered units, both line and battery operated, therefore offer the best of all worlds. To paraphrase a former light heavyweight champion, Tommy Loughran, “Use batter power when you can, line power when you must.”

Posted in Manufacturer News, Product News |

U-SNAP Alliance, Smart Grid and Internet Connectivity Companies

Leading Smart Grid and Internet Connectivity Companies Join U-SNAP Alliance

Alliant Energy, CLECO, Comverge, GE Consumer & Industrial, Portland General Electric, Radio Thermostat Company of America, Sensus, Trilliant and eleven other companies join U-SNAP Alliance in smart grid home area network standard creation.

Morgan Hill, CA. (September 10, 2009) – The U-SNAP Alliance, formed by a group of utility industry leaders to create a low cost connector standard to enable consumer products to communicate with any vendor’s smart meter, announced the formation of the alliance and first members to join the Alliance, bringing total membership to 19 companies.

U-SNAP (Utility Smart Network Access Port) Alliance addresses a key portion of the Smart Grid, the home area network (HAN), where consumer appliances and other energy aware devices talk to smart meters. As the Smart Grid and smart metering market grows, the development of an industry standard to enable plug and play connectivity between smart meters and home networks will be key to the creation and adoption of energy aware devices.

Members of the U-SNAP Alliance represent several key elements of the smart grid ecosystem, including utilities, product design and manufacturing, semiconductors, smart meters, software, thermostats, and in-home displays.

Founding members leading the Alliance at the Promoter level and as members of the Board of Directors are Radio Thermostat Company of America and Sensus. Contributor Members, consisting of product manufacturers, includes Comverge, eRadio, GainSpan, GE Consumer & Industrial, Intwine Connect, NURI Telecom Co., Ltd, Trilliant and ZeroG Wireless. Influencer Members, consisting of non-manufacturers, namely utilities, includes 4Home, Alliant Energy, Benton PUD, Celestica International, CLECO, LS Research, Niagara-on-the-Lake Hydro, Portland General Electric and Our Home Spaces.

“I am quite pleased with the first wave of companies joining the U-SNAP Alliance,” said Jon Rappaport, chairman of the U-SNAP Alliance. “Our rapidly growing membership represents an impressive mix of utilities and appliance manufacturers, and enabling technologies who understand the dynamics of the Home to Grid market and the need to enable connectivity between smart meters and consumer products.”

“There is increasing activity around smart meters and several companies are actively developing U-SNAP compliant products based on the first U-SNAP specification, with the first products appearing on retail shelves later this year,” said Tim Simon, U-SNAP Alliance vice chairman.

More information on U-SNAP Alliance membership, technical specifications, and activities can be found at http://www.usnap.org.

About the U-SNAP Alliance
The U-SNAP Alliance is an open industry association developing an industry standard for connecting energy aware consumer products with smart meters. The Alliance will create and publish a standard, establish testing and certification procedures for product conformance and educate consumers, utilities and vendors on the benefits of the standard. Alliance membership is comprised of utilities, manufacturers, consultants and other parties interested in developing or deploying the standard. For more information, or to find out how to join the Alliance, please visit www.usnap.org.

Member Quotes

4Home
“4Home is a staunch supporter of standardization. We believe that U-SNAP will play an important role in the driving the device interoperability necessary to bring compelling, cost-effective energy solutions to consumers. U-SNAP adoption will allow the 4Home Software Platform to expand its ecosystem of supported devices, thereby increasing the value of the various consumer applications that we create. 4Home is looking forward to our participation and will work diligently to move this initiative forward,” said 4Home President & CEO, Leon Hounshell

Alliant Energy
“Alliant Energy is extremely pleased to be a member and supporter of the U-SNAP Alliance.”, said Gregg Lawry, Director of Energy Delivery Technology.  “The U-SNAP standard represents a major leap forward in establishing a cost effective means of supporting interoperability of utility smart grid systems, customer smart appliances, and Home Area Networks, allowing the use of wireless communications technologies best suited for each application and environment.  We strongly encourage others to consider support of U-SNAP through their membership in the Alliance, and through specification of products that incorporate the U-SNAP standard.”

Celestica
“Supporting the U-SNAP Alliance is part of our ongoing commitment to help our customers embrace and advance environmental technologies,” said, Greg Allen, Vice President, Green Technologies, Celestica. “We believe that the standardized interoperability of products within the HAN is critical to a successful multi-vendor Smart Grid ecosystem and Celestica is focused on supporting technologies and standards that enable our customers to rapidly commercialize products to make the Smart Grid a reality in every home and business.”

Comverge
“Comverge is committed to a more intelligent and integrated electric grid. The U-SNAP Alliance represents a step toward establishing Smart Grid standards that will ensure interoperability and drive the energy industry forward,” said Comverge Interim President & CEO, Michael Picchi.

eRadio
“We applaud the work of the U-SNAP Alliance and are pleased to be an early member of the group.”, said Rick Boland, CEO of e-Radio USA.  “We believe the low cost, easy-to-use common connector approach will accelerate the growth and interoperability of various devices residing on the smart grid.”  “e-Radio looks forward to working with alliance members to integrate its FM-RDS based technology into products that are consistent with U-SNAP standards.”

GainSpan
“While Wi-Fi is widely available, some home area networks use other technologies and the beauty of the U-SNAP Alliance is its goal of achieving a technology-agnostic, universal solution for connecting devices to smart meters,” said Bernard Aboussouan, VP Marketing, GainSpan Corporation.  “Device makers will not have to worry about choosing the right wireless technology and can instead focus on bringing the right products to market.”

GE Consumer & Industrial
“USNAP provides a great interoperability solution for a variety of consumer and utility products during these interim years while Smart Grid communication standards are developed and deployed.  It also provides a format to allow products to be upgraded to new protocols and helps ensure against stranded assets,” said Kevin Nolan, Vice President of Technology.

Intwine Connect
“Our goal is to provide customers with an easy-to-use, low-risk, cost effective solution to enable monitoring and control of their internet connected devices. Intwine’s primary focus is the relevance of our solution in delivering customer value versus being enamored with the enabling technology. To us, technology is simply the plumbing. The benefits our solution delivers to OEM customers are 1) improved brand loyalty due to a positive end user experience  2) providing actionable information to product engineering and marketing research teams by gaining visibility into usage patterns and 3) strengthened relationships with market channel partners by providing a fleet management platform to increase sales of consumables. To consumers, the value of the Intwine user experience is peace of mind knowing their Intwine Connected Home results in enhanced safety, health, energy efficiency, money savings, and fun!”

LS Research
“LS Research has always been a supporter of standards that add efficiency and flexibility to product development. Our strengths in ZigBee, WiFi, Bluetooth and other radio standards is further enhanced with the introduction of U-SNAP as a physical layer interconnection. We have our ModFLEX set of certified radio modules which will fit nicely into the evolution of this up and coming standard. With our enhanced focus on the Smart Energy business which includes our RateSaver Smart Energy approved IHD, U-SNAP gives us yet another tool to help our growing list of utility focused customers” Says Bill Steinike, President of LS Research.

Our Home Spaces
“Our Home Spaces is excited to be a part of the U-SNAP alliance and Radio Thermostat’s product release later this year.” said Jan Peterson, Co-Founder of Our Home Spaces.  “Our involvement with the U-SNAP WiFi module has demonstrated the flexibility and potential associated with this platform and we anticipate the application of the WiFi module to several Home Area Network solutions for both the Smart Grid efforts and communicating appliances.  Integration with user devices, like the iPhone or Widgets, allows the user maximum control and access to their U-SNAP enabled appliances. The U-SNAP Alliance’s mission of creating an open standard for consumer products is critically needed for mass market acceptance of the Smart Grid and Our Home Spaces applauds this undertaking and looks forward to being actively involved with this alliance.”

Niagara-on-the-Lake Hydro
“Our company believes that HAN in every home will become an integral component of the North American Smart Grid.  The U-SNAP product development is expected to overcome a number of technical barriers that stand in the way of this reality,” said Jim Huntingdon, president, Niagara-on-the-Lake Hydro Inc.

Portland General Electric
“U-SNAP makes an important contribution to interoperability by standardizing a physical form factor.  The biggest barrier to demand respond is the cost to install communications at a specific appliance. The low-cost U-SNAP connector makes it relatively inexpensive for an appliance OEM to add the socket without incurring the cost of a communication device.  The standard physical form factor means communication device makers can reach a lower price point because many appliances will use the same communication module. Both of these effects mean lower costs for customers to participate in demand response,” said Conrad Eustis, Director Retail Technology Development.

Sensus
“This plug-in U-SNAP card provides a powerful, low cost solution. It solves a key utility issue-having to choose a HAN communication technology and pay for  it, in all meters, up front and often well before the utility knows  the scope and timing of a demand response deployment. It does this  by using the communications hardware that is already imbedded in  every smart meter, to communicate with a HAN controller embedded in  a U-SNAP device such as a thermostat. Sensus is strongly supportive of this innovative solution,” said H. Britton Sanderford, Jr., Chief Technology Officer.

Trilliant Incorporated
“U-SNAP benefits utilities and consumers by lowering the risk of technology obsolescence,” said Eric Miller, Senior Vice President Solutions for Trilliant. “Prior to U-SNAP, Smart Grid networks relied on an ‘under-the-glass’ implementation of home-networking technologies to enable consumer energy efficiency capabilities. U-SNAP effectively decouples HAN technology from the meter, which allows utilities the flexibility to deploy HAN-based demand-side programs on a per-consumer basis without requiring the adoption of still-evolving HAN standards in every meter. This not only lowers the cost for smart metering but also provides a more future-proof solution for demand response and home energy efficiency.”

ZeroG Wireless
“The U-Snap interface seeks to standardize connection of devices to the smart grid, and we believe this will result in more rapid adoption of Wi-Fi for a variety of customers focused on the home area network (HAN).  We are happy to support the Alliance with our low-power embedded Wi-Fi products to provide our customers with seamless and secure connectivity to the ubiquitous Wi-Fi installed base,” said, David Friedman, senior director strategic marketing.

(Contact Info: U-SNAP Alliance | 408-833-6241| barry@u-snap.org)

Posted in Technology |

Differences between a Function Generator and an AWG ?

Question:
What are the main differences between a conventional Function Generator and an Arbitrary Waveform Generator (AWG)?

Answer:
A function generator has standard, predefined waveforms, i.e. sine, square, ramp and triangle.  The user can manipulate these waveforms by adjusting basic controls such as the duty cycle, amplitude and offset.  On the other hand, the AWG has the ability to generate these standard waveforms of a function generator and allows a user to arbitrarily define and output waveforms.  The keys to reproducing accurate arbitrary waveforms are (1) sufficiently large memory, (2) high vertical resolution and (3) fast sampling rates.  With today’s rapidly evolving technology, AWGs are being used in a growing number of industries and educational institutes.  Industries utilizing AWG technology for high-end test and design include but are not limited to the military, defense, aerospace, propulsion, automotive, power generation and transmission, and industrial control.

Popular AWG’s
BK Precision 4086AWG and 4084AWG - are laboratory grade synthesized function generators with arbitrary capability. Direct digital synthesis (DDS) techniques are used to generate stable, accurate output signals for all 27 built-in standard and complex (arbitrary) waveforms as well as custom arbitrary waveforms.

Posted in Technology, Test & Measurement Tech |

Single Superconductor Cable Can Replace 12 Copper Cable Bundles ?

Barring the occasional thunderstorm, most Americans take the electric current behind their power buttons for granted, and assume the juice will be there when they’re ready to fire up an appliance or favorite tech toy. Little do most know, the strain on our electric grid—which has led to rolling brownouts and the massive 2003 blackout that left 40 million people  across the Northeast in the dark—will only intensify in coming years.

According to the Department of Energy, the annual cost of power outages is approximately $80 billion. Now add to conventional challenges those risks posed by terrorists intent on crippling our economy. Suddenly, the aim of electrical engineers to develop a technology to keep the country’s electrical grid online (and recover faster) really begins to resonate. Taking the juice for granted A single superconducting cable could one day replace a dozen traditional copper cables, freeing up much needed space beneath city streets.

The Science and Technology Directorate (S&T) of the U.S. Department of Homeland Security is currently funding a promising solution—a superconductor cable that would link electrical substations and allow the sharing of excess capacity during emergencies. This generally is not done now, and so a flexibility like this strengthens the resiliency of the overall grid, reducing the likelihood of major power failures. This is S&T’s Resilient Electric Grid project, and the superconducting cable is called an inherently fault current limiting (IFCL) superconductor cable.

Engineers are putting decades of existing electrical research (by industry electricity leaders from American Superconductor, Southwire, and Consolidated Edison) into practice. S&T managers and scientists recently participated in a successful test of the new superconducting technology at the Oak Ridge National Laboratory in Tennessee, as they eye the aging rats’ nest of power cabling under the crowded streets of New York City.

The benefits are simple but profound: these cables can deliver more power, prevent power failures, and take up less physical space. A single superconductor cable can replace 12 copper cable bundles, freeing up more space underground for other utility needs such as water, natural gas, or phone service. The technology is capable of carrying 10 times as much power as copper wires of the same size, while also being able to adapt automatically to power surges and disruptions from lightning strikes, heat waves, and traffic accidents, even sabotage.

“The IFCL superconducting cable being tested could well revolutionize power distribution to the country’s critical infrastructure,” said Dr. Roger McGinnis, Director of the Homeland Security Advanced Research Project Agency at S&T. “Eventually, these technologies will help incorporate localized clean, green electricity generation into the power grid.”

As for the science, the cables work by transmitting electricity with near zero resistance at higher temperatures than usual. But “high” is a relative term among superconductors. The cables conduct electricity at a chill -320°F instead of an icy -460°F for traditional superconductor cables. Holding and conducting energy better than traditional copper means these cables take up a fraction of the space. Manhattan’s electrical workers may be able to eventually clear out the subterranean congestion beneath Wall Street that amazingly, looks much the same today as it did a century ago. Since the cables themselves better prevent extremely high currents from cascading through the system, they will help eliminate the power surges that can permanently damage electrical equipment, similar to a breaker switch in a home, explained McGinnis. The cable switches off during a surge or failure, but automatically resets when conditions return to normal.

For some context, electrical substations take electricity delivered over transmission and distribution lines and lower the voltage so it can be used by homes and businesses. Even if power is lost to an individual substation, by creating multiple, redundant paths for the electric current, the cables allow quick power restoration to all the surrounding power loads. Ultimately, these cables may allow substations that had been intentionally isolated from one another in the past, for fear of cascading failures, to be interconnected in order to share power and assets.

Cutting-edge high temperature superconducting cables have been successfully tested in laboratories, and can be found in a handful of demonstration projects around the country, but they remain an emerging technology. S&T is interested in advancing the technology so that it can be used nationwide, and is pursuing an opportunity to connect two Con Edison
Manhattan substations with the cable. The Department of Homeland Security hopes to enable the Department of Energy and various utility companies around the country to replace more than 2,000 circuit miles of power cables in U.S. cities with resilient, safe, and green IFCL cables.  (Source U.S. Dept. of Homeland Security—Science and Technology)

Following are some grid test solutions from Chroma

Chroma 66201Power Meter 10mA minimum current range / 1mW

Chroma 66202 Power Meter Embedded high speed DSP, 16 bits Analog/ Digital converters, 10 mA minimum current range and 1 mW power

Posted in Applications, Technology, Test & Measurement Tech |