Form, fit, & function in $1500 DSOs
Contents
1. 100 Msampless _ r hy m oy T s 210 DC I21AN IG Scopetfeter 123 NISTO ia 100 1 io 100 1 10 nadie mfr pide pn piy pricey mei Timebase seting This DSO feels and looks as if it s virtually indestructible and it certainly lives up to its Industrial ScopeMeter title Its easy to operate although it has only twenty buttons to control its many functions Performance is basic though most notably with only 512 samples channel Compared against the other DSOs it lacks cursors and zoom It does measure inputs up to 600 V RMS though and has an in built 5000 count DMM The DMM measures Ohms continuity diodes dBV dBm crest factor and amps and temperature with optional probes The unit also graphs max min readings from 120 s to 16 days 198w The printout via the optically isolated RS 232C interface replicates the display with a secondary ignition automotive signal input 2002 02 05 Pico Scopes Distributed by Interworld Electronics amp Computer Ind Inc sales interwld com Page 6 of 8 what as you manoeuvre your mouse pointer over the display The wide range of around 40 preset measurements that you can apply to waveforms is a particular strong point and displaying these measurements as a list in a separate window neatly keeps the main virtual front panel uncluttered NI is currently revamping the software that supports its NI 5102 hardware and Ni S2. 331 ksamples You can extend the record length to 16 Msamples by using the PC s internal memory Because it is a plug in card and is available in PCI PXI USB ISA and PC Card formats the NI 5102 offers the best connectivity and system integration possibilities Fluke s ScopeMeter 123 is a good example of a versatile handheld instrument From a performance only viewpoint though you d never choose it because of its low bandwidth and sampling rate Furthermore its record length 512 samples channel is positively minute and its display is small What Fluke compromises in speed and memory it makes up for in electrical and mechanical protection Input voltage protection is often an underrated instrument feature but it is certainly important on this DSO Users commonly measure AC mains voltages and carefree probing with the other DSOs we tried spells instant death to the unit The Fluke unit though handles these voltages without incident As a further plus handheld units use batteries so you have no concern about ground loops common mode errors or safety isolation on your measurements As a bonus the ScopeMeter also provides a 5000 count DMM lt sales interwld com gt 2002 02 05 Pico Scopes Distributed by Interworld Electronics amp Computer Ind Inc sales interwld com Page 3 of 8 Ease of use is essential If you re a bench hardened veteran you ll feel at home with the benchtop TDS210 PC based DSOs just can t match the
3. V div V div compromises For example e d aie anno eee Timebase 20 nsto5 5 us to 100 100 ns to 50 Snsto5 you get with a larger Idi Idi Idi Idi scope In addition you can t SAY eae svar Pe output records or remotely you buy options The options Sones will cost you around 50 of Size in 91hx4 5w PCI ISA 5 5h x 7 5 6hx12w the base unit alone So while x2d plug in card wx 1 8 d x 4 75 d you may prefer a benchtop J instrument the final price of Weight Ibs 2 9 Not 2 the Tek TDS210 may exceed applicable your budget l Power supply mains mains l adapter or adapter PC plug ins and externals rely rechargeable battery on the host computer for their 5 hr optional display power supply front panel and possibly their Price 4195 1295 aie igs enclosure As a result you can i i often enjoy benchtop performance at a much lower cost Pico s ADC 212 100 PC external DSO delivers and it s a good value In fact it s the only unit we used that has 12 bit vertical resolution and 61 vertical accuracy Its software lets you operate the module as a scope spectrum analyzer DMM or square wave generator Surprisingly National Instruments NI 5102 PCI plug in DSO which you would imagine has the lowest manufacturing cost comes out as the most expensive unit we tried It is also the most limited in bandwidth sampling rate and input voltage In its favor though the NI 5102 has the highest record length per channel by far
4. Probe Strengths and weaknesses If you really need a portable and rugged instrument CHT iim CAS Sin M Tis CHT 7 10 then give strong consideration to Fluke s ScopeMeter Model 123 It is easy to use but its measurement CHI vertical potion A04 dive 40i lt sales interwld com gt Figure 2 The Tek TDS210 zooms in on the same signal as in Figure 1 but shows large amplitude variations and individual waveform points capability is a bit limited compared with the others Tek s benchtop TDS210 is a pleasure to use but the internal noise displayed on the unit we used even on higher ranges put us off ibe sili a fe ajo fua 1 oo Ds Te a alar ajdi National Instruments NI 5102 performs well but its 15 MHz bandwidth and 20 Msamples s rate give you the lowest specs for the highest cost of the DSOs we used Also we think the lack of a waveform recall ability in the SFP 1 5 software is a significant drawback The plug in card s system s integrative T potential is one feature that the other formats can t a rival ET aye It s hard to find fault with Pico Technology s ADC 212 100 except that you do have to live with a rather unspectacular looking plastic box The box belies what must be within though because the software gives you other virtual instruments and its specs fall at the better end of the range even with the lowest price of the units we tested T amp MW iia iL oe d H
5. Tek unit stores five Data storage lends an inherent advantage to the PC plug in and PC external DSO formats Effectively you get free waveform recording with unlimited storage The Nl Scope Soft Front Panel SFP software version 1 5 which now ships with the NI 5102 lets you save waveform data to a file for analysis in a spreadsheet or math package Although SFP 1 5 lets you store waveforms it doesn t let you recall waveforms to the display Although PC displays suffer none of the viewing limitations of the 100 mm LCDs on the Fluke and Tek units NI s SFP 1 5 currently prevents you from maximizing your display window and the software lacks measurement cursors and waveform zoom facilities SFP also prevents you from shifting the waveform relative to the graticule such shifting is an analog scope legacy that lets you use the graticule for rough amplitude measurements To its credit though Nl s SFP lets you choose from up to 40 different waveform measurements per channel in a separate window Pico Technology s ADC 212 100 PC external module doesn t have the constraints of the NI plug in The PicoScope software lets you store unlimited numbers of waveforms or measurements and you can maximize the 10x10 graticule and virtual front panel to take advantage of a PC s large display You also can select the colors for each trace background and cursor What you win on display with PC externals and plug ins though you lose on usability
6. feeling of satisfaction and precision that you get when you adjust a scope with a knob You simply don t need handbooks or help files to operate this DSO The only notable limitations concern the TDS210 s display The eight vertical grids by 10 horizontal grids although bright and with good contrast have a narrow viewing angle Viewed from directly in front the black and white B amp W LCD is easy to read But readability quickly diminishes as you move off center The fold out feet tilt the case up by 208 an adjustable angle would make the display more visible Fluke s handheld ScopeMeter 123 also has an 8x10 display graticule or more accurately about 91 visible horizontal divisions on the model we used The display s brightness though is a drawback Even with the backlight on you ll need to shield the display when taking readings in bright light Fluke designers made the 123 easy to use with only 20 front panel buttons The standard Tek and Fluke units lack connectivity when you need to record waveforms Considering these units will find use primarily as waveform monitors rather than as design tools this lack of connectivity isn t a problem Both units can store waveforms and front panel setups but you ll need to purchase additional attachments to download records to a PC Without these attachments the units limit you to storing just one waveform per input channel The Fluke unit lets you store 10 front panel user setups the
7. Fingers on knobs and buttons will always beat mouse or keyboard operation Although NI s SFP and Pico s PicoScope software make the PC units easy to use you have to accept Windows style pull down menus to set up your scope NI also provides shortcut keys on your keyboard to operate these controls Zoom highlights differences Operating on the theory that this class of instrument best suits monitoring work we tested the units using video signals and noise signals On all units the automatic setting located an initial waveform that we then adjusted manually to give similar displays across all units We looked at the color sync burst of a video signal using the DSO zoom feature of the Tek and Pico units Fluke s handheld unit and NI s PC plug in have no display zoom so they couldn t undertake this test This measurement highlighted differences between the Tek and Pico units The color burst the ripple in Figure 1 that follows the low going sync pulse should be 8 to 11 cycles long We wanted to see how well the Tek and Pico scopes could zoom in on the 4 43 MHz color burst The lt sales interwld com gt 2002 02 05 Pico Scopes Distributed by Interworld Electronics amp Computer Ind Inc sales interwld com TDS210 displayed a waveform that varied wildly and the trace broke down into individual dots Figure 2 Pico s PC external DSO with 12 bit resolution produced a particularly good waveform at a similar magnificati
8. Pico Scopes Distributed by Interworld Electronics amp Computer Ind Inc sales interwld com Page 1 of 8 Articles Reference Software About Us TestsMeasu rement Buyer s Guide Product Info Shows amp Courses WORLD Submissions Subscriptions Marketing Home Test amp Measurement World February 2002 Form fit amp function in 1500 DSOs We looked at four low cost DSOs in handheld PC plug in PC external and benchtop formats with similar specs By Brian Kerridge Editor Test amp Measurement Europe and Martin Rowe Senior Technical Editor If you re buying a low cost digital storage oscilloscope DSO and have a budget of around 1500 you have several form factor options handheld PC plug in PC external or benchtop Each form factor has special requirements Handheld DSOs must be small and robust Designers of PC plug in cards must shrink measurement circuits and the cards need to operate within the noisy PC environment PC plug ins and PC externals both abandon conventional front panel controls and displays for mouse keyboard and monitor operation Benchtop formats may suffer none of these compromises but manufacturers have to balance features against price to compete in the low cost market With these issues in mind we assessed the measurement performance and usability of these four low cost DSOs e Fluke handheld 123 ScopeMeter 1195 e National Instruments PCI plug in NI 5102 1295 e
9. Pico Technology PC module ADC 212 100 1079 and e Tektronix benchtop TDS210 1195 Table 1 compares the key For a summary of what s benchtop formats included in each standard package see below Company National Pico Tektronix Instruments Technology We recommend that you use the DSOs in this class for Format handheld PCI plug in PC module benchtop 123 monitoring and recording known signals but not to probe Model NI 5102 ADC TDS 210 for the unknown One unit has with NI 212 100 lt sales interwld com gt 2002 02 05 Pico Scopes Distributed by Interworld Electronics amp Computer Ind Inc sales interwld com Page 2 of 8 a shortage of digitizing speed and another has short memory Scope Soft with length such limitations Front Panel PicoScope diminish the appeal of these software software units for use in design applications But if you needa Bandwidth 20 MHz 15 MHz 50 MHz 60 MHz scope for waveform monitoring or simple troubleshooting Max sampling 25 20 100 1 these instruments should meet rate Msamples s Msamples s Msamples s Gsample s your technical and budgetary requirements Record 512 samples 331 128 2 5 length channel ksamples ksamples ksamples Price vs features You might expect a benchtop eSP IED instrument to have many pros 5 o a o tai accuracy occupies little bench space ee a 5mVto500 125mVto 2mvto2 2mvio5 though Tektronix made some sensitivity V div 1 2 Vidiv
10. al Contact National Instruments Austin TX 512 794 0100 www ni com Pico Technology s ADC 212 100 This unit is the only one in the survey with 12 bit vertical resolution and it shows as generally smoother waveforms It also shifts the 0 4 theoretical limit with 8 bit resolution DSOs down to less than 0 1 The DSO also usefully includes a record length of 128 ksamples channel or 256 ksamples to a single channel Zoom operates on both X and Y scales A useful save to disk on trigger function allows you to trap record and time date intermittent events over long periods The unit also includes as standard a square wave generator a 50 MHz 4096 point spectrum analyser a 4 digit true RMS DMM and a transient recorder Getting this DSO running including loading the PC software is straightforward and takes less than two minutes The software with free downloads includes 35 automatic measurements including rise time pulse width duty cycle THD SNR and SINAD A 5 hour battery pack is optional and makes this unit reasonably portable when used with a laptop Pico s unit is compatible with C C Delphi Visual Basic LabView Agilent Vee Linux and Excel In Excel a macro allows you to directly collect data without scope or logging software lt sales interwld com gt 2002 02 05 Pico Scopes Distributed by Interworld Electronics amp Computer Ind Inc sales interwld com What you get for 1079 PC Scope
11. cope Soft Front Panel has replaced the earlier VirtualBench Scope Several earlier standard features such as zoom maximised window and cursors have yet to be added to the SFP The issue 1 5 available for our survey allows you to store waveform data but not recall waveforms to the display The software revamp employs Hierarchical Data Format HDF which will allow you to use third party applications that support HDF to access stored waveforms In this file format you can store full details of waveforms such as vertical range sampling rate trigger information with your data The great advantage of this digitiser is its 331 iailonal iestruments PESIO at FAQ 3 ksamples channel record length which in the future you can expand to 16 million samples if your PC has 48 Mbytes of free RAM This unit s real strength is as a dedicated systems digitiser though and it comes in other systems formats such as CompactPCI PCMCIA and USB It s also compatible with Nl s LabView and Measurement Studio and with MS Visual C C and Visual Basic Overall this digitiser is pleasant to use but its lt SMM costly for what is quite a modest measurement specification in this class of instrument i ee What you get for 1295 PCI plug in card NI Scope soft front panel SFP software 1 1 SFP usefully displays the actual sampling rate on each switchable x1 x10 probes user manual software _ timebase setting user manu
12. get for 1195 Benchtop DSO x10 probes user s manual Page 7 of 8 i wii Fii ito ime E re Possted ly E Mie fl 1ra Errr piia e r be l FE d ar BL i Hiii The 12 bit resolution provides more amplitude detail to the secondary ignition automotive input signal compared with the other DSOs in this class 3 mnpm ee io M Poe b20ms Hard Copy gt Fami 7 Peat 4 3 i i Abor i l Hardcopy CH ZIN CHE TOV Sits AN The printout using the hard copy button shows all details of the DSO s display using the secondary ignition automotive input Contact Tektronix Beaverton OR 800 426 2200 www tektronix com Copyright 2002 Test amp Measurement World Published by Cahners Business Information Newton MA E mail Site Map Editorial Staff Sales Staff Cahne Help KANNETS Copyright 2002 Cahners Business Information a division of Reed Elsevier All rights reserved Privacy Policy Trademark Information amp Terms of Use lt sales interwld com gt 2002 02 05 Pico Scopes Distributed by Interworld Electronics amp Computer Ind Inc sales interwld com Page 8 of 8 Test amp Measurement World 275 Washington Street Newton MA 02458 1630 USA Tel 617 558 4671 Fax 617 558 4470 E mail amp Webmaster tnw cahners com Web Site Developer WebGrow lt sales interwld com gt 2002 02 05
13. ie Lt Gere Eee Figure 3 Zooming in on the 4 43 MHz color burst sync section with the Pico ADC 212 100 produces a Brian Kerridge has been writing on electronics respectable waveform design and test for 10 years with both EDN and Test amp Measurement Europe magazines He has 25 years of experience in design engineering management and marketing of T amp M machine control electronics and military radar He is a Chartered Engineer and MIEE 2002 02 05 Pico Scopes Distributed by Interworld Electronics amp Computer Ind Inc sales interwld com Page 5 of 8 Martin Rowe has a BSEE from Worcester Polytechnic Institute and an MBA from Bentley College Before joining T amp MW in 1992 he worked for 12 years as a design engineer for manufacturers of semiconductor process equipment and as an applications engineer for manufacturers of measurement and control equipment E mail m rowe tmworld com Sampling rate rolls off Although tens of Msamples s sounds like a lot of sampling is going on in fact DSOs of all classes can only maintain their real time sampling rates if there is an adequate record length channel As an example for the Tektronix DSO in this survey the 1 Gsamples s rate operates with only 2 5 ksamples channel buffer memory which means the DSO can sample at full speed for only 2 5 ms a 400 kHz waveform period before its memory buffer is full To record for longer this DSO has to spread its available record le
14. module switchable x10 x1 probe kits PicoScope software CD mains adapter parallel cable user s handbook Contact Pico Technology Cambridgeshire UK www picotech com Sold in North America through Interworld Electronics 877 902 2979 www interwld com Tektronix s TDS 210 This DSO has the feel of a regular bench scope It s pleasant to use and has a bright LCD Its strengths are its 60 MHz bandwidth and 1 Gsamples s sampling rate although its limited 2 5 ksamples channel record length rather negates the sampling rate advantage Automatic measurements include period frequency RMS mean and peak to peak Zoom operates in both X and Y scales Giving this DSO some connectivity or expanding its measurement capability makes its already higher cost start to get expensive The field fittable TDS2CM communications module adds a Centronics parallel port RS 232C and IEEE 488 programmability Module TDS2MM adds the previous I O and also a 2048 sample FFT and automatic measurements of rise fall times and positive and negative pulse widths If you want to operate the DSO from a PC you ll also need WaveStar PC software The Tek screen shots included in this survey came via the parallel printer output and don t do justice to the neatness of the DSO s display Apart from cost the only real concern you might have about this DSO is its visible trace noise which makes you want to reach for a focus control What you
15. ngth over increasingly longer periods and in consequence reduce its sampling rate each time you increase the timebase setting The chart shows how the sampling rates of all the DSOs in our survey roll off with timebase setting Fluke s ScopeMeter 123 adapter cable Battery power runs the unit for five hours four hours with backlit LCD Actual mpling tate 1 Grantpless 4 TO Varies 4 1 Aeamnplesk d 100 Ksanpless 10 Ksampess Although the 123 has a 20 MHz input bandwidth at its BNC terminals the standard probes supplied by Fluke limit measurements to only 12 5 MHz bandwidth You ll have to buy the optional 10 1 probe kit to get the full bandwidth If you need to link up your 123 to a PC to archive results for example then you ll also need the optically isolated RS 232C and takes four hours to recharge with the unit off A useful battery refresh feature allows you to put the batteries into an internal 12 hour cycle which fully discharges and then recharges them What you get for 1195 Handheld DSO DMM Ni Cd pack power adapter charger 1 1 probe kit 70 page users manual Contact Fluke Everett WA 425 347 6100 www fluke com National Instrument s NI 5102 This DSO or digitiser as NI prefers it is easy to operate with pull down menus or shortcut keys A selectable context help window is useful for reminding novice users what controls lt sales interwld com gt e a a
16. on Figure 3 Using the cursors set on the 11 cycles of Pico s zoomed waveform we measured a frequency of 4 49 MHz against a 4 43 MHz target color burst signal We ran a test to check the internal noise of all four scopes You can easily apply this test to any DSO by connecting a terminated short at the input BNC The NI 5102 showed slightly more noise and using its peak to peak measurement facility we read 1 95 mV pk pk on the DSO s 12 5 mV div lowest range ui eall ye Te l gl to w de sf Page 4 of 8 me fon al In a similar test Tek s TDS210 showed 1 8 mV pk pk italia ica a at 2 mV div and strangely this varied with timebase Figure 1 A typical video signal on the Pico ADC setting Even on all the higher volts div ranges the 212 100 prior to using zoom Tek unit always showed a quarter of a graticule s worth of fuzz Fluke s 123 measured 0 0 mV pk pk on Tek M Stop Wi Pos L000 us CHT 5 mV div although we observed a tiny ripple on the D E aik aani hahh Aiid siii rian trace Pico s ADC 212 100 measured 318 mV pk pk an on a 1 mV div setting poe Et Linit l l l Tir di To put the results of the noise test into perspective TES GHEE Lait i GoM we ran the test on a 20 year old analog scope Our AREN ENI mi voti HP1740A displayed far less internal noise than any of eee yee ead the DSOs we tested On a 1 mV div setting we could l il E see about 200 mV of pk pk noise E
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