Today’s multimeters are packed with next-gen features

These meters are equipped with capabilities like faster response rates, ability to provide relevant information and more reliable results, besides many other physical attributes

By Richa Chakravarty

Friday, July 18, 2014:  Multimeters have evolved into high-end electrical testing equipment. The current market trend and a clear change in customer preferences indicate that the industry is moving towards more advanced multimeters, specifically those equipped with capabilities like faster response rates, the ability to provide relevant information and greater reliability.

A multimeter is mainly used to measure the three basic electrical characteristics of voltage, current and resistance. There are two primary types of multimeters—analogue and digital. Each is designed to measure the same basic electrical values, but differ in their method of measurement and display. The analogue models were developed first, and rely on a moving pointer over a graduated scale to indicate readings. Digital meters use a liquid crystal display (LCD) or light emitting diode (LED) to display readings numerically.

What’s new in the market?

Today, most multimeters can measure a wide variety of properties including conductance, resistance, inductance and frequency. Some of them can also measure temperature and duty cycles. The most advanced models have the capability to measure rotations per minute, decibels and microamps. These advanced multimeters have become easy to handle and are more rugged as they have waterproof casings and graphing capabilities. They also come with a variety of accessories including probes, clamps and leads. Some multimeters may come with extra batteries and product warranties that are valid from one to three years. Here are some of the new models in the market.

Meters with a dual display: In the past two decades, the test and measurement (T&M) industry witnessed a shift from analogue to digital technology. Now the shift is towards information-rich displays. Displays used in digital multimeters (DMMs) are undergoing changes. Today, multimeters come with dual display technology which enables quick diagnosis in real time. “DMMs are evolving to include even more measuring functionality along with better display methodology. The new models include the capability to display two readings such as voltage and temperature, at the same time,” informs Prince, product manager, Rishabh Instruments Pvt Ltd.

Fluke’s 287 and 289 handheld meters are the next generation meters with high performance industrial logging feature. They have 320×240 video graphic array (VGA) display to show multiple readings for easy review of the logged data.

GW Instek’s GDM-834x series, launched in August 2013, is equipped with dual display to support various combinations of measurements. “The result of different measurements simultaneously appears on different displays, which saves users time and the trouble of selecting displays while reading measurement results,” says Sumit Sharma, marketing manager, India, Good Will Instrument Co Ltd.

The GDM-834x series also offers three selectable measurement speeds—fast, medium and slow. For instance, DC voltage measurement can reach 40 readings per second on the fast mode, which maximises the effectiveness of each measurement. This mode comes with the convenient USB flash drive storage function, integrated with 12 major measurement items and many auxiliary functions, such as maximum/minimum values, reading hold, relative values, dB, dBm, algorithms and comparison.

In November 2013, Rishabh Instruments launched a new range of multimeters with the dual display system, including the Rishabh 410, 612, 613, 615 and 616 models. The dual display of these meters provides multiple parameters on the same screen, which helps in faster yet reliable analysis of measurements. The 66-segment analogue bar graph scale visualises the variations in readings, making it more convenient and effective. The display is equipped with higher digit counts for better resolution.

“Engineers require effective visualisation of measurements for better interpretation of results and faster decision making. This is often achieved through in-built displays or advanced computer integration. Our latest multimeters continue to grow in functionality and utility to cover the ever increasing measurement challenges,” says Prince.

Wireless/handheld meters: Along with benchtop DMMs, handheld meters are also becoming more powerful for troubleshooting. Customers can today monitor multiple circuits simultaneously on a single DMM, see live trends on a computer or laptop and log the readings at the same time.

Adding to the list of handheld meters, Fluke launched the CNX DMM in 2013, which is a wireless system that offers more than a traditional multimeter. CNX uses Zigbee radios with a proprietary overlay to communicate wirelessly. Zigbee allows users to connect with up to 10 CNX modules at one time and consumes least power, which maximises battery life. The module battery typically lasts up to 400 hours, which adds up to more than 15 days of continuous recording. It has an inbuilt memory of 65,000 data points, making it an extremely powerful data logging device.

Informs Prashant Jain, senior product manager, electrical, Fluke India, “Fluke CNX is a set of wireless test tools working together. Launched by Fluke in India, with the CNX system, users can take measurements that are remote, simultaneous and recordable. They can take readings and solve problems faster, thereby reducing downtime and increasing productivity.”

Metro Electronic Products offers Mastech’s MS8240D handheld autoranging DMM that provides a USB interface and analysis software. It tests AC/DC voltage and current, resistance, frequency, duty cycle and capacitance, simultaneously.

Meters with advanced computer integration: With the advances in application-specific integrated circuits (ASIC), the capabilities of a multimeter have improved significantly. Multimeters now possess advanced computer integration enabled through RS 232, wireless or Bluetooth technologies. The interface allows the computer to record measurements as they are made. Some DMMs can store measurements and upload them to a computer, cutting down on time spent and resulting in a higher level of convenience. These DMMs also have features like autoranging, auto polarity, sampling and hold, graphic representation of the selected quantity under test, data acquisition features, etc. “Today’s demanding applications need more than just a multimeter. Customers need to log data over a period of time and download it to a PC for further analysis. Fluke provides powerful software—FlukeView Forms which can be used to download data onto PCs/laptops,” informs Prashant Jain.

“Multimeters are getting sleeker, even as they become rich in features like incorporating a wider range of parameters in a single instrument. Also, their connectivity to laptops and PCs for data analysis ensures much needed convenience to the user,” says Manish Kwatra, managing director, Metro Electronic Products Ltd.

Ideal Industries offers multimeters with advanced computer integration and many features. “Everything that is needed is in the package, including software, USB cable, test leads with alligator clips, a K-type thermocouple and a sturdy protective carrying case. Its high frequency rejection (HFR) mode provides accurate voltage/frequency readings on non-sinusoidal wave forms, such as adjustable speed motor drives,” says Chirag Lodhiya, regional sales, electrical division, Ideal Industries India Pvt Ltd.

How to choose the right multimeter

The wide choice available in the market, ranging from lower end basic multimeters to higher end advanced multimeters, can confuse users, making it difficult to select the right multimeter that will meet their requirements and, at the same time, offer the maximum value for the price paid. Here are a few parameters users could evaluate before making a final purchase decision.

Bench-top or handheld? Multimeters come in both handheld and bench-mounted variants. Bench-mounted devices are reportedly more accurate than the handheld ones, but a handheld multimeter is more convenient as it can be taken anywhere. So users should be very clear about the type of meter that suits their requirements.

Accurate measurements: Accuracy is the first parameter one should check in a meter before buying it. For example, if you want to discriminate between a circuit that is working poorly from one that is working perfectly, you will need a meter with a higher accuracy level than what low end meters offer. Also, if accuracy matters a lot to buyers, they should go in for a multimeter that can be calibrated. They must also check whether annual calibration is required and, if so, the cost and turnaround time involved.

Display: One should spend some time to define one’s display requirements. Essential parameters to consider here are display size, display count, backlight, analogue bar graph scale and other troubleshooting indicators.

Safety features: Before purchasing a multimeter, buyers must ensure that it complies with international safety norms like IEC 61010-1 and is suitable for the desired protection class (CAT IV/III/II/I). This applies not only to the multimeter but also to probes and any other accessories that come with the device.

Speciality features: The user must also look for features like capacitance measurement, temperature measurement, frequency measurement, and more advanced features like minimum-maximum record, data logging, trending, harmonic ratio, voltage sensing and voltage rating.

Physical attributes: Users should check the physical attributes as well, like size, ruggedness, weight, warranty, battery life—all of which govern the overall life of the multimeter.

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