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PICOTEST M3510A 6½ Digit Multimeter The M3510A is a fast, accurate 6½ digit bench-top multimeter with 4-wire resistance measurement, thermocouple support and a USB interface. Its maximum ratings are 1000V DC and 10A and it can take up to 50,000 readings per second. Review by Nicholas Vinen www.siliconchip.com.au siliconchip.com.au April 2010  75 T he PICOTEST M3510A benchtop multimeter has an impressive array of features. It is a great deal more accurate than a typical hand-held multimeter and comes with a calibration certificate. Precision figures are provided for each measurement mode over various lengths of time, up to 1 year. Accuracy for most readings is in the order of ±0.01%. It has a very fast measurement update rate; up to 50k samples per second. While the display is not updated anywhere near that rapidly, it is still noticeably faster than most other multimeters – even other bench meters. When it is in auto-ranging mode you do not have to wait long for it to find the correct range for your measurement. Alternatively, you can select the appropriate range yourself using two front-panel buttons. To take maximum advantage of the fast measurement rate you need to connect it to your computer – more on that later. While a bench multimeter takes up more space than a hand-held unit, in some ways it is more convenient to use. The controls and connections are easier to access and the display is easier to read. They also tend to have more features, better performance and since they run off mains power, you never need to worry about a flat battery. The main body is 227mm wide, 305mm deep and sits 150mm high with the handle set up as a tilting bail. It has a 2-line orange-on-black backlit LCD with quite a wide viewing angle which is better to the left than to the right. Since the connectors are on the right side, this means it is best located on the right side of the bench. On the rear panel are BNC trigger inputs and outputs, a USB socket, an IEC power socket, an earth screw and the optional GPIB/RS-232 interface connector. Two high quality needle probes are provided in the box. detectors) and thermocouples are supported. The M3510A is supplied with a K-type thermocouple and it has internal cold junction compensation. This is a major selling point for this unit as temperature can be read out with up to four decimal places, although the actual accuracy of the reading is only about one degree. Measurement modes Interface and useability The main modes are DC volts and amps, AC volts and amps (with true RMS), 2-wire or 4-wire resistance, capacitance, frequency, continuity, diode test/forward voltage and temperature. In DC volts mode, the input impedance is 10GΩ (gigaohms) for ranges up to 10V and 10MΩ for higher ranges. This can be overridden if you want 10MΩ impedance for all ranges. The 10GΩ mode is very handy for measuring voltages with a very high source impedance. This is because much less current is drawn from the point you are measuring than a typical hand-held multimeter. The 4-wire resistance mode allows for much more accurate measurement of smaller value resistors, with readings down to 0.1mΩ (milliohms). Practically speakingthough, readings below 10mΩ are hard to make accurately, due to temperature drift, noise and probe resistance, even in the 4-wire mode. To use the 4-wire mode you will need to add another pair of probes or buy one of the optional accessories such as the OPT07 Kelvin Probe Set or OPT08 4 Wire Test Probe. For temperature measurements both RTDs (resistance temperature Using this multimeter for basic measurements is a joy and its fast updates are a revelation after using typical handheld digital multimeters. Its capacitance mode ranges from fractions of a picofarad up to thousands of microfarads – very handy indeed. Connect virtually any unknown capacitor and you will have its value, although larger capacitances can take several seconds to measure. The frequency measurement mode is very accurate but does not have a very wide range – only 3Hz to 300kHz. The update rate is automatically adjusted and is quite fast except when measuring very low frequencies. The interface is easy to use and it responds instantly to button presses. Pressing each button generates a beep but that can be disabled. All the most important functions take just one or two button presses. There is also a menu system, which is used for changing the configuration and to enable the various mathematical modes. Sometimes it isn’t entirely obvious where a given option will be in the menu but there are not so many that it takes very long to go through them all. Options available through the menus include changing the ADC sample Sheet1 Current 0.9 Value DateTime : ( 10 / 02 / 24 -- 13 : 10 : 14 ) 0.8 0.7 0.6 0.5 Current 0.4 0.3 0.2 0.1 0 13:04:48 This oversize photo shows the supplied thermocouple: it’s tiny (the silver blob at the end of the wire). It’s so small that at first, we didn’t think it had been supplied. 76  Silicon Chip 13:12:00 13:19:12 13:26:24 13:33:36 13:40:48 13:48:00 13:55:12 14:02:24 14:09:36 The charging current flowing into a small SLA battery. Current measurements were taken once per second and when finished we imported the CSV file into OpenOffice to draw the chart. siliconchip.com.au period, ratio measurements, averaging, limit testing, min/max readout, mX+b readout, dB readout and auto-hold. More commonly used mathematical operations such as offset nulling and filtering are provided directly via buttons on the front panel. The “DIGITS” button allows for selectable precision in all modes. As you increase the number of digits, the update rate slows down but even in 6.5-digit mode it is quite fast. In addition there are several filter settings which can be used to further adjust the speed/precision trade-off. The 2-line display means that in virtually every mode it is possible to make two measurements at once. However, because the acquisition circuitry is shared, the ground reference terminal is common and the update rate is reduced in dual display mode. While it is very handy, for the aforementioned reasons the dual measurement function isn’t quite as good as having two separate meters. For example, you can measure voltage and current at the same time but they must both be relative to the same point in the circuit. While in dual measurement mode, a relay click is evident each time the display is updated, unless one measurement is from the thermocouple input. Computer interface While some high-end hand-held multimeters do provide computer connectivity, the M3510A takes it to a whole new level. Plugging it in means, essentially, that you have added a very accurate and high speed ADC to your computer, with all the front-ends the multimeter provides. As already stated, to make use of the maximum 50k sample rate you need to hook the multimeter up to a computer via the provided USB cable. This allows you to use it as a data logger. You can use the fast sample rate to record what happens in a circuit over a short period or else set the rate lower, for long-term logging. The software provided is simple but does the job. You can select any of the main measurement modes from the GUI and once you choose an update rate and click “play” it begins logging data. It can later be imported into Word or Excel via a CSV (comma separated variable) file. The drivers on the provided CD were too old to work with Windows 7 64-bit edition but a newer version is available for download which solves this problem. At the time of writing, the software does not support logging multiple inputs in one session but we have been informed by the distributor that a new version, which can do so, should be available around the time this goes into print. Overall, we are impressed with the PicoTest M3510A. Its ease-of-use, accuracy and features combine to make this a powerful test instrument. Availability The M3510A is available from Westek for AU$825.00 plus GST and delivery. The M3511A model with 10k/s sample rate and no thermocouple input is AU$692.00 plus GST and delivery. In both cases the standard warranty is one year but it can be extended at additional cost. To contact Westek, call (03) 9369 8802 or e-mail info<at>westek.com.au. For further information visit www. westek.com.au SC Radio, Television & Hobbies: the COMPLETE archive on DVD YES! NA MORE THA URY ENT QUARTER C NICS O R T C E OF EL R O T HIS Y! This remarkable collection of PDFs covers every issue of R & H, as it was known from the beginning (April 1939 – price sixpence!) right through to the final edition of R, TV & H in March 1965, before it disappeared forever with the change of name to EA. For the first time ever, complete and in one handy DVD, every article and every issue is covered. If you’re an old timer (or even young timer!) into vintage radio, it doesn’t get much more vintage than this. If you’re a student of history, this archive gives an extraordinary insight into the amazing breakthroughs made in radio and electronics technology following the war years. And speaking of the war years, R & H had some of the best propaganda imaginable! Even if you’re just an electronics dabbler, there’s something here to interest you. • Every issue individually archived, by month and year • Complete with index for each year • A must-have for everyone interested in electronics Please note: this archive is in PDF format on DVD for PC. Your computer will need a DVD-ROM or DVD-recorder (not a CD!) and Acrobat Reader 6 or above (free download) to enable you to view this archive. This DVD is NOT playable through a standard A/V-type DVD player. Exclusive to SILICON CHIP $ ONLY 62 00 +$7.00 P&P HERE’S HOW TO ORDER YOUR COPY: BY PHONE:* (02) 9939 3295 9-4 Mon-Fri BY FAX:# (02) 9939 2648 24 Hours 7 Days <at> BY EMAIL:# silchip<at>siliconchip.com.au 24 Hours 7 Days BY MAIL:# PO Box 139, Collaroy NSW 2097 * Please have your credit card handy! # Don’t forget to include your name, address, phone no and credit card details. siliconchip.com.au BY INTERNET:^ siliconchip.com.au 24 Hours 7 Days ^ You will be prompted for required information April 2010  77