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Recording, saving and sharing readings precisely

TRUE RMS digital multimetre with logging function and Bluetooth® connection to BENNING app for smartphones and tablets.

BENNING’s powerful MM 12 logging multimetre is ideal for service and maintenance engineers who work with complex, problematic industrial applications in electrical systems (CAT IV 600 V/CAT III 1000 V), power distribution systems and in automation and electrical engineering, handling demanding measuring tasks in development and laboratories, and also industry and electrical specialisms, using the smartphone app to forward measured data to the team so that they can examine and analyse the data.

POWER news (Pn) spoke to Mr. Tobias Enck of BENNING’s testing and measurement equipment department about the multimetre’s main functions and benefits.

Pn: Mr. Enck, what makes BENNING’s new MM12 digital multimetre so interesting to users?

Enck: As measuring tasks become increasingly complex, the demands on measuring systems also rise. Precise readings, regardless of the environment, are important for diagnosing and solving problems. By recording measured values and displaying them as graphs on your PC monitor, smartphone or tablet, you can see anomalies, solve problems and minimise downtimes more quickly. I’d also like to mention how easy they are to use. You can change settings easily via the central navigation key, which you can also use to quickly select menu functions and sub-functions. The BENNING MM 12 has individual setting facilities for LCD lighting, automatic shutdown and setting threshold values when conducting continuity tests. You can also activate and deactivate the signal tones and saving readings automatically, and set the LCD readout display in two sensitivity ranges with higher and lower digits.

Pn: There’s no doubt the BENNING MM 12 is a first-class measuring device. Its specifications and description reflect its many functions, and the certificate of calibration that comes with it is a testament to its top quality. But what makes this measuring device different from those of other manufacturers in comparable performance segments?

Enck: I'm glad you mention the specific performance features. There are comparable measuring devices, of course, but they’re generally much more expensive. A good price-performance ratio – and this applies to all our testing and measurement systems – is something you’ll find with all BENNING products. Meanwhile, people are aware that our measuring devices always come with software (with no licence fees), protective bags and extensive accessories at no extra charge, unlike those of most other manufacturers.

Pn: Let’s remain a little longer on the subject of costs. How expensive is recalibration?

Enck: The BENNING MM 12 comes with a certificate of calibration. Recalibrating it at the factory costs € 81.20, whilst a DAkkS recalibration is € 103.75. We plan to keep operating costs stable in the long term, so users will be able to budget for these.

Pn: What are the BENNING MM-CM-Link app’s strengths, and how does the application work in practice?

Enck: Installing the app and setting up the link is child’s play. Once you’ve activated the Bluetooth® functions, just select the measuring device in the app. Now you can record data in real time, send it wirelessly and display it continuously as a graph, or specify a target file and start recording a series of readings, precisely setting the cycle time between two readings in advance. You can link up to five BENNING MM 12s at any time and divide the screen up as you want, so you can see all the graphics together. And once you’ve completed and saved recordings, you can email them for analysis.

Pn: Can you say which applications highlight BENNING MM 12’s benefits?

Enck: Not long ago now, one of our clients said they wanted to take and record multiple measresistance readings when making the final checks on their product. The unit saves measured values as soon as they stabilise, so that this is possible. Other applications are in problematic electrical installations, controls and systems. Viewing them via smartphone or tablet means you can stay a safe distance from an object if it is in a risk area. Measuring devices which meet development and laboratory requirements must work reliably and take readings precisely. The BENNING MM 12 can monitor and record systems and processes for many hours at a time.

Pn: Can you tell us something about the measurement functions, Mr. Enck?

Enck: The measurement functions cover everything you’d expect from a measuring device, including current, voltage, resistance, frequency, capacity and temperature, as well as continuity and diode testing. And, if measuring currents up to 10A does not suffice, you can use a clamp adapter like the BENNING CC 3 to extend the measuring range up to 300 A AC/DC. The input sockets have a 1000 V overload protection feature in all functions; and if you connect the mA and A range sockets the wrong way around, the BENNING MM 12 emits an audio alarm and the display reads ‘ProbE’ as a warning.

Pn: Are there any other special features which could be of interest to users?

Enck: Switching to a lower input impedance (LoZ < 3 kΩ) when measuring voltages can be used to suppress reactance voltages; and you can also trip an FI/RCD residual current device in this mode if phase and protective earthing conductor are in contact. The resulting leak current is around 75 mA. This test does not meet the guidelines for testing fixed electrical systems, as the leak current is not precisely defined and no trip time is measured; but it shows the protective earth is connected correctly.

One major extra feature that the BENNING MM 12 has is a low-pass filter (HFR) for taking precise voltage and frequency readings on drives and other electrical equipment where the basic frequency is overlaid by harmonics. This has proved itself to be particularly important for industrial use.

Pn: Both the measurement categories, which define the application areas for measuring devices,
and measuring procedures in complex systems are major selection criteria. How does the BENNING MM 12 perform here?

Enck: It meets the requirements of the highestrated measurement category, CAT lV 600 V / CAT III 1000 V. As voltage is always stated relative to earth, the phase-to-phase voltage can be 1.732 (√3) times higher, so the measured voltage can be > 1000 V. As you would expect from measuring devices in this performance class, we use the TRUE RMS (root mean square) measuring method to measure AC voltage and current, enabling you to measure asymmetric voltages and currents, which vary from the basic sinus shape precisely. Asymmetric voltages occur mostly in the case of power controllers like dimmers, speed controls, cycle-timed switch controls, pulsedloading devices and electronic speed controls in modelling, etc. With such special measuring tasks, conventional average measuring devices sometimes produce extreme deviations in measurement.

Pn: Finally, could you please give us a few details about the BENNING MM 12's memory and logging capabilities?

Enck: You can record up to 100,000 measured values via the software when connected to a PC. Our internal data logger (LOG) can save 40,000 and the memory function (MEM) 1,000 measured values. We also have a measured value and peak memory, relative measurement, displaying maximum, minimum and average values and level measurement.

Pn: Many thanks for sharing all of this, Mr. Enck.

BENNING MM 12 connected directly to a PC to record up to 100,000 measured values
BENNING MM 12 connected directly to a PC to record up to 100,000 measured values
Connect up to five BENNING MM 12s by Bluetooth® to our free app BENNING MM-CM-Link Implemented images: app display and delivery contents
Connect up to five BENNING MM 12s by Bluetooth® to our free app BENNING MM-CM-Link Implemented images: app display and delivery contents

Further Information

author/contact: Tobias Enck
telephone: +49 2871 93 111

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