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PICOSCOPE 5444D MSO -  USB Oscilloscope - Review

Scoring

Product Performed to Expectations: 8
Specifications were sufficient to design with: 9
Demo Software was of good quality: 7
Product was easy to use: 9
Support materials were available: 9
The price to performance ratio was good: 9
TotalScore: 51 / 60
  • RoadTest: PICOSCOPE 5444D MSO - USB Oscilloscope
  • Buy Now
  • Evaluation Type: Test Equipment
  • Was everything in the box required?: Yes - Just a minor issue, no CD, installation instructions on PicoLog instead of PicoScope.
  • Comparable Products/Other parts you considered: A whole range of other USB and desktop scopes.
  • What were the biggest problems encountered?: Problems specific for the macOS version of PicoScope, and particularly the SDK. Had quite some problems getting the Python wrapper up and running.

  • Detailed Review:

     

    Introduction

    First, I want to thank Element14 and PicoTech for giving me the opportunity to review this great and valuable test equipment.

     

    History

    Until four years ago all my measurements were relying on an old analog 15 MHz TRIO oscilloscope.Then I switched to a Siglent 70MHz digital scope, which was a big improvement, I could do measurements which I only could only dream of before, like evaluating the pulse train of a 433 MHz domotica receiver. Then from February 2014 onwards I got the opportunity to review a number of oscilloscopes for Element14.

    • The first one was the Picoscope 2205A which is a PC based oscilloscope, with its particular advantages and disadvantages. You can read about my findings here: Picoscope 2205A Oscilloscope - Review

    • After that I was chosen to road test the TBS1202B-EDU, which specifically was designed for educational purposes. I have to say that I'm impressed with the high quality and rich feature set of this scope. You can find my  findings here: Tektronix TBS1202B-EDU Oscilloscope - Review
    • Then I did a review of the  BitScope Micro, featuring a tiny mixed signal oscilloscope in a probe. I mainly tested its functionality on a Raspberry Pi.  My review can be found here: BitScope Micro Oscilloscope & Analyzer - Review

     

    Roadtest plan

    In my roadtest application I offered to review the PICOSCOPE 5444D MSO based on the following points:

    1. As you can read in my TBS1202B-EDU review, it standard can store 2.5k samples, which is not much. If you need to troubleshoot a signal, the problem needs to be close to the trigger in order to be seen. Surprisingly, my cheap chinese Siglent scope has a memory depth which is 8 times larger (2MS). The 5444D MSO Digital Oscilloscope is much better in this sense, with Deep capture memory – from 128 million to 512 million samples. I would rather like to test that, also in connection to the following point.
    2. Its capability of Automated Serial Protocol Analysis for 18 different protocols. For my latest design challenge application I interfaced Nixie tubes by I2C from an Intel Edison, using PCF8574 IO Expanders ([Upcycle It] Nixie Display #5 - I2C Interface to display drivers). For the roadtest I'm planning to monitor the I2C lines and unravel the protocol.
    3. I'm also very curious to the performance of the FlexRes flexible resolution, with 1 GS/s sampling at 8-bit resolution 500 MS/s sampling at 12-bit resolution 62.5 MS/s sampling at 16-bit resolution. I will test this feature by analysing high frequency signals with different FlexRes settings. As I am a ham radio operator, I have several HF sources at my disposal.
    4. In my Picoscope 2205A Oscilloscope - Review I complained about the absence of a native macOS version of the PicoScope software. Luckily PicoTech listened to me and since summer 2014 PicoScope also runs native on macOS. I will specifically have a look how this works.
    5. For the evaluation I let me be guided by the excellent articles on reviewing oscilloscopes by Colin O'Flynn of circuit cellar, using the

     

    For the convenience of the reader, here some links to information I used when performing this roadtest review.

     

    What is in the box

    Here are the images of the package contents:

    {gallery} What is in the box

     

     

    Package Contents as listed in the specifications, listed on the PicoTech website:

    PicoScope 5000D Series oscilloscope

    1 x TA155 Pico blue USB 3 cable 1.8 m

    60 MHz models: 2/4 x TA375 probes

    100 MHz models: 2/4 x TA375 probes

    200 MHz models: 2/4 x TA386 probes

    4-channel models: 1 x PS011 5 V 3.0 A PSU

    MSO models: 1 x TA136 MSO cable

    MSO models: 2 x TA139 set of MSO clips

    Quick start guide

     

    As we have the 200MHz, 4 channel MSO model, there is a PSU in the box, and 4 TA386 probes. Not mentiond in the list is the 'AN INTRODUCTION TO PICOSOPE' poster. In the past there was a CD with software in the box (like in my previous 2205 review and in the video of Colin O'Flynn). Looks like PicoTech decided not to provide software CD's anymore, which in my opinion is a right decision since nowadays it doesn't make much sense to distribute software on a CD, as it is much easier to download the most recent versions from the internet.

    Regarding the 'Quick start guide' I was a bit confused, as it is the guide for the USB Data Logger. Also not mentioned in the content list is the etui with zipper for storing he MSO cables and clips. My first thought was that is was a carrying case for the scope itself. Considering portability, it would be handy to have something that protects the BNC connectors. PicoTech sells a case (https://www.picotech.com/accessories/miscellaneous/hard-carry-case-medium ), which might be worthwhile when using it portable.

     

     

    Teardown

    A real engineer likes (needs) to know what's in his equipment, therefore in this section you will find a teardown of the Picoscope.

    First of all a very interesting teardown of the PicoScope 5444D (not the MSO version of this roadtest) by Dave Jones from EEVblog:

     

    Below is a slideshow of my own teardown. It appeared to be very easy to take the scope apart. Just 6 screws in total hold everything together.

    The PCB is different form the one above in the teardown of Dave Jones. So PicoTech uses different PCB's for each model in stead of omitting to populate part of the PCB for scopes lacking the digital inputs for instance. This is easy to understand, as the front and back pannel layout is different for these models. Compared to the plain 544D, the signal generator output of the MSO version is on the back in stead of the front pannel. Also the external trigger input is completely missing in this case.

     

    {gallery} Teardown

    PicoScope 5444D MSO teardown: top view

    PicoScope 5444D MSO teardown: remove front and back rubbers

    PicoScope 5444D MSO teardown: bottom view, including specs and SN

    PicoScope 5444D MSO teardown: remove 4 screws

    PicoScope 5444D MSO teardown: remove bottom cover

    PicoScope 5444D MSO teardown: bottom side PCB, remove 2 screws

    PicoScope 5444D MSO teardown: remove top cover

    PicoScope 5444D MSO teardown: top side PCB

    PicoScope 5444D MSO teardown: ADC, opamps and part of the power circuit

    PicoScope 5444D MSO teardown: FPGA and memory

    PicoScope 5444D MSO teardown: shielded input circuits

    PicoScope 5444D MSO teardown: high quality shielded BNC busses

    PicoScope 5444D MSO teardown: view from the front

    PicoScope 5444D MSO teardown: FPGA, USB and ADC

    PicoScope 5444D MSO teardown: DAC (signal generator)

    PicoScope 5444D MSO teardown: digital inputs

     

     

    Below is a top picture of the PCB, with the most important components labeled.

     

    Besides the different layout compared with the plain 5444D version, I found another remarkable difference, as the ADC type is different from the one Dave Jones mentions above.

    Dave mentions the ASD 5020 while in this version the HAD 1520 is used. A small internet search learned me that the ASD 5020 was from 'Arctic Silicon Devices', a Norway-based fabless semiconductor company. In 2011 ASD was acquired bu 'Hittite Microvave', which in turn was acquired by Analog Devices in 2014. (https://www.analog.com/en/landing-pages/001/analog-devices-welcomes-hittite-microwave-corp.html ). I expect that the HAD 1520 which is from AD, is the successor of the ASD 5020. More info here: https://www.analog.com/en/products/hmcad1520.html.

    Specifications of the AD 9744 signal generator: https://www.analog.com/en/products/ad9744.html .

     

     

    Functional evaluation and test

     

    • Topic 1-1: Do You Want a PC-Based or Stand-Alone Instrument?

    Colin gives a nice consideration for choosing a pc-based or stand-alone instrument. Personal preference determines your choice.

    It is clear that the PicoScope 5444D is a PC-Based instrument. I have some experience with different scopes, from an old analog low bandwidth to nice digital bench top scopes from Siglent and Tektronix scopes with bandwidths up to 200 MHz. I also did a review of the entry level Picoscope 2205A Oscilloscope - Review.

    The Siglent and Tektronix are equipped with an usb port and can also be operated from a PC. I have to say that I never used this option, I prefer to use a scope standalone. On the other hand the PicoScope is rather small and can easily be taken with you in your laptop bag. As nowadays laptops are very common, there is a much larger interest in small portable scopes.

    The 5444D is a very compact (190 x 170 x 40 mm including connectors) and light ( < 0.5 kg) device. The necessary cables (USB and analog/digital probes) doesn't need much space and can be stored in the provided etui.

    The device comes with a power supply, but If only two of the four analog channels are required, the supplied USB cable is sufficient to power the device. To use all four analog channels, or if the USB port provides less than 1200 mA, then connect the supplied AC power.

    It is clear that for portable use the PicoScope has a lot of advantages. A major advantage is the large screen of your laptop where you can display several signals at once in high resolution.

    Another advantage is that screenshots and data already are on your laptop, so no need to transfer them for further processing using USB sticks.

    A big disadvantage of the picoscope is that there are no knobs. When peeking and poking in my electronic designs to find the fault, or try to tune the circuit to its best performance, I like to press buttons or tune knobs, in stead of choosing menu items and fill in input boxes. But as already said this is a strict personal preference.

    And if you really need knobs, you always can tinker a control box together with an Arduino (http://colinoflynn.com/2014/01/making-a-usb-hid-keyboard-encoder-board-for-picoscope/ ).

     

    • Topic 1-2: Where’s the Ground?

    Where is the ground is an important question for all scopes, but you have to be careful when your measurement ground is equal to the USB ground,  for the 5444D as wel as for the previous tested 2205A this is the case. This also is nicely depicted on the front and back pannel where you can see that the 5V ground, USB ground and all BNC connectors are connected.

    So be careful when using the device, you need to ensure there isn’t a voltage difference between the ground of your device under test and the computer.

    Of course this is the same for a desk top scope, but for a PC/portable scope combination it's easier to do it wrongly.

    The manual of the scope is clear enough:

     

    • Topic 1-3: Input Types

    Looking at the specs, the capabilities of the PicoScope5444D are quite advanced. Four inputs with a max rating of ± 20V pk (same as 2205A). So with the probe at 10:1 the input range is ± 200 V. Compared to my Tektronix TBS 1202 with an input of 300V this is a bit limited.

    The minimum range is ± 10 mV, 5 times less than the 2205A. The input input impedance is 1Mohm and 14 pF.

    Input can be either AC or DC. 50 ohm input, which often is used for RF applications is not available. As many other manufacturers, PicoTech has a range of inputs for different bandwidths and models. For example, this model, from the 5000-series, which has up to 200-MHz bandwidth, has DC/AC high-impedance inputs. The 6000-series has DC/AC/DC 50 inputs for 500-MHz bandwidth and below. The 6000 series in 1,000 MHz bandwidth only has 50-Ω input impedance.

    The 200MHz  bandwidth is equal to my Tektronix and 8 times more than for the 2205A.

     

    • Topic 1-4: Probe Quality and Type

    The scope comes with four standard probes (part number TA386). The probes are rated at 10 MHz for 1:1 attenuation and 200 MHz for 10:1 attenuation. The quality looks reasonably, it doesn't have a spring-loaded tip, but the size of the tip is pretty small. The switch for attenuation and the compensation trimmer are on the probe head. There are even plastic guard add-ons, which fit standard surface mount device (SMD) sizes (e.g., 1.27 mm, 1 mm, 0.8 mm, 0.5 mm) to probe TQFP/SOIC/TSSOP packages. Coloured clips can be placed on the cable for labeling the different channels. Compared to my Tektronix TPP0201 probes, I prefer the latter, for several reasons:

    • the probe is smaller, the compensation trimmer is at the plug instead of the probe. Attenuation is fixed at 10:1, but that is not a big deal to me.

     

    Tektronix

    PicoTech

    • Cable is thinner and more flexible.
    • It has a flat hook instead of a bend wire.

    • Shielding tube is not fixed (can easily be removed) including ground connection.

     

     

     

    • Topic 1-5: Digital Input?

    This RoadTests scope is equipped with digital inputs which I personally am quite happy with. Whether you see this as an advantage or not, is  somewhat of a personal choice: You may wish to have a separate stand-alone digital analyzer, or you may wish to have it built into your oscilloscope. Colin O'Flynn choses to have a stand-alone digital logic analyzer, as digital logic analyzers are available at a fairly low cost from a variety of manufacturers. In his experience, the cost of purchasing a separate PC-based logic analyzer is considerably lower than the “incremental cost” of selecting an oscilloscope with logic analyzer capabilities compared to one without.

    Be aware though that you can't trigger on the digital signals. You always need to connect one of the digital signals to a analog input for triggering (see also topic 3-5).

    Lets have a look at the costs of the MSO version:

      • price difference between the plain and the MSO version is 250 €.
      • the signal generator output connector is on the back of the unit compared to the front for the non MSO version, to me that is a minor disadvantage.
      • the external trigger input is lacking on the MSO version, with four available channels this is not a big disadvantage to me, see for further comments topic 4-2.

     

     

    • Topic 2-1: Analog Bandwidth

      • probe bandwidth

    First I checked the bandwidth of the probe, with attenuation of 1:1 the bandwidth is 10 MHz according to the specs.

    Here you see a 10 MHz 1V signal from the internal signal generator:

    Then I increased the frequency until the signal is 3dB lower (0.7 V). As you can see this is at 15 MHz.

    At an attenuation of 10:1 the bandwidth 200 MHz according to the specs. Unfortunately I don't have a calibrated signal generator going up in frequency  that far. Below you see the same signal as was used in the previous test, added with 20 MHz. As you can see the signal increases a bit, which I expect is due to cable impedance. I have to investigate a bit more in this. The strengt of the effect was anyway dependent on the length of the cable from the signal generator to the probe.

      • HF signals

    For high frequency signals I used my ham radio transceiver, at 144 MHz (below the 200 MHz bandwidth) and 433 MHz (two times the 200 MHz bandwidth). Below you see the signals. The 144 MHz signal looks nice, The 433 MHz is a bit worse.

    Note that the frequency measurement nicely shows the exact transmitted frequency.

     

     

     

    • Topic 2-2: Sample rate

    The sample rate of the 5444D is 1 GS/s, or one sample per ns. To demonstrate this I connected a RF noise source, with a bandwidth of 3 GHz.

    Here the signals with a time base of 1, 10 and 100ns/div:

     

    In the graph below, just 1 sample/div is measured, I expect that the line drawn is interpolated over the measured points.

    A frequency of 100MHz is measured, but that is by coincidence.

    Here 10 samples per devision are sampled.

    here 100 samples per devision are sampled.

    The 1 GHz sample rate is for all channels in total. When turning on the second channel, the sample interval per channel automatically adjusts to 2 ns.

    Turning on the third channel adjusts the sample interval to 4 ns. Note that the collection time switches to 5 ns, which is the closest available option.

    And finally when turning on the fourth channel, the sample interval keeps at 4 ns.

     

    • Topic 2-3: Equivalent Time Sampling

    With 8 or 4 samples per period  you can't give a good visual representation of your signal, luckily this scope does have equivalent time sampling (ETS) mode, which makes it possible to show more samples when measuring periodic signals. The caveat is that this high sample rate is achieved by doing careful phase shifts of the A/D sampling clock to sample “in between” the regular intervals. This requires your input waveform be periodic and very stable, since the waveform will actually be “built up” over a longer time interval. Read the articles of Colin O'Flynn for a detailed description of this mode.

    I know you can't count a noise signal as periodic and stable, but lets just give it a try:

    As you can see the sample interval now is 100 ps. And the measured frequency is around 2 GHz.

    When setting the time base at 1 ns/div, the signal shows much higher frequency than you saw before, with ETS off.

     

    • Topic 2-4: ADC Resolution

    The standard resolution of this scope is 8 bit, resulting in 2^8 = 256 different quantisation levels. For visual evaluation of your signal on the screen this is fine, but when you do some calculations, for instance FFT to show the frequency the result is hampered by quantization noise. A very nice and important feature of the 5444D is the ability to switch between 8/12/14/15/16 bits on the ADC input. There’s some restrictions there – for example if you want 16 bits, you can only use a single input channel. In addition the sample rate decreases to 62.5 MS/s at the 16-bit range. Pico advertises this as FlexRes, and it actually is a feature of the HAD1520 ADC.

    What is FlexRes?

    Pico FlexRes flexible resolution oscilloscopes allow you to reconfigure the scope hardware to increase either the sampling rate or the resolution. This means you can reconfigure the hardware to be either a fast (1 GS/s) 8-bit oscilloscope for looking at digital signals, or a high-resolution 16-bit oscilloscope for audio work and other analog applications. Whether you’re capturing and decoding fast digital signals or looking for distortion in sensitive analog signals, FlexRes oscilloscopes are the answer.

    It’s important to realize this is different from ‘software resolution enhancement’ which I explained in my Picoscope 2205A Oscilloscope - Review. You are actually changing the sampling resolution of the ADC.

     

    Below you can see the effect of the resolution setting. The first image is a triangle wave of 1 kHz, 1V peak, captured at 8 bit, input range 2V.

    Then I switch the input range to 20V and zoom in on the signal. You clearly see the quantisation levels.

    One quantisation step can be calculated by full-range voltage/2^8, = 40/256 = 0.16V.

    When switching to 200V range and zoom in once more, one quantisation step is 1.6V, as you can see the triangle wave is not visible any more.

    Now when we switch to 16 bit, the triangle is back again. A quantisation step for 16 bit is 400/2^16, is 6 mV.

     

     

    • Topic 3-1: Memory depth

    Compared to the 2205A, the memory depth of the this scope is huge, 512 million samples compared to 16 thousand. PicoTech advertises this feature as Deep Memory:

    Deep memory enables the capture of long-duration waveforms at maximum sampling speed. In fact, the PicoScope 5000D Series can capture waveforms over 500 ms long with 1 ns resolution. In contrast, the same 500 ms waveform captured by an oscilloscope with a 10 megasample memory would have just 50 ns resolution.

    Below is an example of the value of this feature. In the upper window you see a 1 kHz square wave from the internal signal generator. It looks like there is some overshoot on the edges.

    I opened a second window, with the same signal, and zoomed in a factor of 1000, which in detail shows how the overshoot looks like. I come back to this in topic 4-3.

     

     

    • Topic 3-2: FFT Length

    Since the FFT is done on the PC it outperforms desktop oscilloscopes. Where a desktop oscilloscope only has 4096 or 2048 bins for the FFT, on the PC you can set a much larger buffer.

    When doing the FFT to use the scope as a ‘spectrum analyzer’, you are always starting from 0Hz. So if you want to measure the bandwidth of a narrow-band signal at for instance 5 MHz, you will always need to cover the ‘useless’ range from 0-4 MHz. With a 2048 point FFT,  when zooming in on the bandwidth of interest, you’ll end in a very poor resolution.

    With the 5444D you go up to a buffer size of 1 M samples, which makes it possible to zoom in on very narrow signals:

    Below you see an example of a FFT of a sine wave at 5 MHz, on the Tektronix TBS 1202B desktop scope, and on the PicoScope application using different buffer sizes.

     

    The Tektronix:

     

    PicoScope, with buffer size of 2048, signal is similar to the Tektronix:

    PicoScope, with buffer size of 65k, 5 MHz sine wave is nicely shown as a single peak in the frequency domain.

    Be aware that the FFT is done on the PC. When switching to FFT mode, my PC fan started blowing noticeable, and the CPU Load increased a lot.

     

     

    • Topic 3-3: Segmented buffer

    Depending on the settings you have chosen, PicoScope may store more than one waveform in its waveform buffer. When you click the Start button or change a capture setting, PicoScope clears the buffer and then adds a new waveform to it each time the scope device captures data. This continues until the buffer is full or you click the Stop button. You can limit the number of waveforms in the buffer to a number between 1 and 10,000 using the General preferences page. Using this option you can set the scope to trigger on a event, and then it wil record a number of wavelengths. You now can search for abnormalities in the saved buffers.

    Here is an example video, a sweep of a 1-3 kHz square wave. After stopping the acquisition I stepped backward through the buffers, showing the signal in earlier stages:

     

    • Topic 3-4: Remote Control/Streaming

    PicoScope SDK

    The remote control/streaming option means that the scope can be controlled from a PC, using dedicated software, but also using general software like Matlab, Python, C, C++, .net etc. Where most modern desktop scopes have this option, for the PicoScope this is a key concept. The main software, is PicoScope, on which I come back in topic 3-6.

     

    Besides the full-function PicoScope software, there is also a SDK (software development kit) available to use the PicoScope from your own applications.

    For this new scope version (D) it was not very clear where the SDK could be downloaded. In the end for macOS it appeared to be hidden in the PicoScope application bundle folder.

    Here is a copy of my request to PicoTech support:

    ==========

    Dear PicoTech support,

    I’m currently doing a Element14 roadtest review of the PicoScope 5444D MSO.
    I’m running into issues regarding the SDK.
    As mentioned on your forum: https://www.picotech.com/support/topic39461.html<https://www.picotech.com/support/topic39461.html>
    And discussed on element14: https://www.element14.com/community/roadTests/1982/l/picoscope-5444d-mso-usb-oscilloscope <https://www.element14.com/community/roadTests/1982/l/picoscope-5444d-mso-usb-oscilloscope>

    Can you please provide me with the interim PicoSDK for macOS 64 bit.

    Thanks a lot,
    Gerrit.

    ==========

     

    Hi Gerrit,
    Thank you for your email.
    If you download the PicoScope 6 software Mac version, and follow the steps on this forum post and copy the libps5000a for PicoScope 5000 series devices using the ps5000a API functions.
    Kind regards
    Xuejie

     

    Pico Technical Support Team

     

    Example software and wrappers for a large number of programming languages and tools can be found on the PicoTech GIT repository: https://github.com/picotech.

     

    Making the Python wrappers work

    For this roadtest I tried to get the python interface working: https://github.com/picotech/picosdk-python-wrappers.

    To be honest this was not a piece of cake, but luckily thanks to the information from Ulrich Thiel (https://ulthiel.com/vk2utl/picoscope-python-interface-under-mac-os-x/ ) I finally succeeded. As the information from Ulrich is a bit outdated, using previous versions of the wrapper and software, I here describes all the steps I did:

     

      • Step one - clone the most recent python wrapper from GitHub:
    gerrit picotech $ git clone https://github.com/picotech/picosdk-python-wrappers.git
    Cloning into 'picosdk-python-wrappers'...
    remote: Enumerating objects: 138, done.
    remote: Counting objects: 100% (138/138), done.
    remote: Compressing objects: 100% (64/64), done.
    remote: Total 803 (delta 89), reused 113 (delta 74), pack-reused 665
    Receiving objects: 100% (803/803), 201.07 KiB | 675.00 KiB/s, done.
    Resolving deltas: 100% (536/536), done.
    gerrit picotech $ 

      • Step 2 - modify picosdk-python-wrappers/picosdk/library.py

    The usual way to include a library, is by adding its path to the DYLD_LIBRARY_PATH environment variable which is taken into account by find_library. But for some reason no matter what this variable is set to, it will be empty in Python! But the variable LSST_LIBRARY_PATH can be imported. So the workaround is to set the DYLD_LIBRARY_PATH inside Python to LSST_LIBRARY_PATH, by adding the following lines to the end of the import section in picosdk-python-wrappers/picosdk/library.py:

     

    # Set DYLD_LIBRARY_PATH
    import os
    from sys import platform
    if platform == "darwin":
        os.environ["DYLD_LIBRARY_PATH"] = os.environ["LSST_LIBRARY_PATH"]

     

     

      • Step 3 - build and install the wrapper:
    gerrit (master *) picosdk-python-wrappers $ python setup.py install --user
    running install
    running build
    running build_py
    creating build
    creating build/lib
    creating build/lib/picosdk
    copying picosdk/functions.py -> build/lib/picosdk
    copying picosdk/ps4000a.py -> build/lib/picosdk
    copying picosdk/library.py -> build/lib/picosdk
    copying picosdk/ps3000.py -> build/lib/picosdk
    copying picosdk/device.py -> build/lib/picosdk
    copying picosdk/ps2000a.py -> build/lib/picosdk
    copying picosdk/ps4000.py -> build/lib/picosdk
    copying picosdk/discover.py -> build/lib/picosdk
    copying picosdk/ps6000.py -> build/lib/picosdk
    copying picosdk/constants.py -> build/lib/picosdk
    copying picosdk/__init__.py -> build/lib/picosdk
    copying picosdk/ps2000.py -> build/lib/picosdk
    copying picosdk/ps5000a.py -> build/lib/picosdk
    copying picosdk/ps3000a.py -> build/lib/picosdk
    running install_lib
    running install_egg_info
    Writing /Users/gerrit/Library/Python/2.7/lib/python/site-packages/PicoSDK-1.0-py2.7.egg-info

     

      • Step 4 - add the library folder to the LSST_LIBRARY_PATH environment variable:

    This can be done temporarily with:

    export LSST_LIBRARY_PATH=$LSST_LIBRARY_PATH:/Applications/PicoScope\ 6.app/Contents/Resources/lib/

     

    But better is to do this permanently by adding this line to the file ~./bash_profile and

    source ~/.bash_profile

     

    Or open a new terminal.

     

      • Step 5 - making path changes to the libraries:

    We still get errors, related to relative path settings which needs to be fixed. Details can be found at Ulrichs website (https://ulthiel.com/vk2utl/picoscope-python-interface-under-mac-os-x/ ).

     

    Here the commands which made it work for me:

     

    sudo install_name_tool -add_rpath /Applications/PicoScope\ 6.app/Contents/Resources/lib/ /Applications/PicoScope\ 6.app/Contents/Resources/lib/libps5000a.2.dylib 
    
    sudo install_name_tool -change libiomp5.dylib /Applications/PicoScope\ 6.app/Contents/Resources/lib/libiomp5.dylib /Applications/PicoScope\ 6.app/Contents/Resources/lib/libpicoipp.1.dylib
      • Step 6 - test:
    gerrit picotech $ python
    Python 2.7.10 (default, Aug 17 2018, 19:45:58) 
    [GCC 4.2.1 Compatible Apple LLVM 10.0.0 (clang-1000.0.42)] on darwin
    Type "help", "copyright", "credits" or "license" for more information.
    >>> 
    >>> 
    >>> from picosdk.discover import find_all_units
    >>> 
    >>> scopes = find_all_units()
    dlopen(libiomp5.dylib, 1): image not foundERROR: Cannot load library libiomp5.dylib
    dlopen(libpicoipp.dylib, 1): image not founddlopen(libiomp5.dylib, 1): image not foundERROR: Cannot load library libiomp5.dylib
    dlopen(libpicoipp.dylib, 1): image not founddlopen(libiomp5.dylib, 1): image not foundERROR: Cannot load library libiomp5.dylib
    dlopen(libpicoipp.dylib, 1): image not founddlopen(libpicoipp.dylib, 1): image not founddlopen(libpicoipp.dylib, 1): image not found>>> 
    >>> for scope in scopes:
    ...     print(scope.info)
    ...     scope.close()
    ... 
    UnitInfo(driver=<picosdk.ps5000a.Ps5000alib object at 0x10a0ff610>, variant='5444DMSO', serial='...../....')
    >>> ^D

    As you can see the find_all_units, nicely detects the 5444D MSO. There are still image not foundERRORs, these are there since I only did step 5 for the 5000A library. These can be fixed by running the install_name_tool also for the other scopes libraries.

     

     

    Unfortunately the story didn't end here, after I successfully could communicate with the scope from Python, the PicoScope software itself could not find the device anymore. I expect step 5 bricked it. I solved it by copying the library to a separate folder, and deleting and reinstalling the PicoScope 6 application.

     

     

    Remarks on streaming

    I was particularly interested in streaming mode where data streams directly over the PC USB3 interface. Currently no Python streaming examples are available. This feature is considerably more complex to work with than simple PC-based control, as achieving fast streams via USB is not trivial. However, using streaming mode opens up many interesting features. For example, you could use your oscilloscope as part of a software defined radio (SDR). I didn't unfortunately find much examples, but given the 5444D specs, with high dynamic range (16 bit) and sample rate, I expect you can create a high performance SDR receiver, similar or better than the Red Pitaya. If anybody knows some examples, please let me know.

     

    • Topic 3-5: Decoding Serial Protocols

    As promised in my application, I would like to test I2C decoding on my latest project ([Upcycle It] Nixie Display - Index).

    Here are the pictures of the setup:

    One of the first things I encountered is that you can not trigger on the digital signals. So I connected the A channel to the I2C clock signal for triggering.

    Initially, I was under the belief that it is not possible to trigger on digital inputs, but thanks to genebren I found that I could select digital channels from the advanced trigger menu.

    For details see topic 4-1.

     

    From the digital channels menu I selected TTL for the level, and D0 and D1.

     

    From the serial decode settings I selected D1 as data, and D0 as Clock:

    here is how this looks like, it clearly shows the address and data of the seconds digits of my Nixie clock.

    A little bit weird to me is the information in the Properties window, where the input level is displayed as 1.5V, while I clearly selected TTL (5V).

    In the serial decoding window you can find the detected data in all buffers. You can see the seconds passing by, you also see that the update rate is faster than 1 second, which corresponds to the software implementation ([Upcycle It] Nixie Display #10 - Software stuff ).

     

     

    • Topic 3-6: Software Features

    When I did my Picoscope 2205A Oscilloscope - Review no native macOS version of PicoScope was available. So I'm very happy that PicoTech made their software available to Linux and macOS. The first macOS beta version of PicoScope was released in 2014. Now in 2018 the software unfortunately still is in beta. My impression is that it works quite robust, but it is lacking features. I didn't find any information on the PicoTech website on this, so below is a list of issues (besides the SDK issues mentioned above) I found when playing with the device.

     

      • DeepMeasure, is not available:

     

      • Buffer overview button not available.

    This is from the PicoScope Manual:

     

    Here is my buffer navigation toolbar:

     

     

      • Limited view options

    Options for viewing information in different windows is rather limited. The grid layout is not available, this is from the manual:

    And this is from my screen:

     

    Below a 4 window PC screen dump from the PicoTech website:

    And this is how a 4 window screen looks on macOS:

     

    These are the examples I came across when playing with the software, it is possible that there is more, but as I said before I  didn't find any information on this.

     

    • Topic 4-1: Triggering Methods

    The PicoScope has several powerful triggers, like simple edge, advanced edge, window, etc. Some of them are a combination of other trigger types

    When selecting a trigger method the software gives a brief explanation with a picture of the signal. Compared to a bench top scope this is very helpful.

    The usefulness of all of these trigger types depends on how unique the signal is that you want to analyse. Typically the simple edge trigger is sufficient. For all my experiments done in this review I only used the simple edge trigger.

     

    Initially, I was under the belief that it is not possible to trigger on digital inputs, but under closer review I found that I could select digital channels from the advanced trigger menu:

    As can be seen in the image triggering can be done on a combination of all digital inputs, checking for 0, 1 and rising or falling edge.

    It is even possible to combine analog and digital triggers using some logic:

     

    • Topic 4-2: External Trigger Input

    Most oscilloscopes also have an “external trigger input.”, the 5444D - MSO has not! I expect that there was no space left on the PCB and the enclosure due to the digital inputs. The non MSO version does have an external trigger input on the frontpage. Of course, you can use one of the four inputs as an external trigger, but this will cost you bandwidth, since your trigger channel does count against the “ADC channels.” So no full sample rate on one channel and trigger on another, or four channels with external trigger with this scope.

     

     

    • Topic 4-3: Arbitrary Waveform Generator

    The 5444D is equipped with a so called arbitrary waveform generator (AWG). It is the BNC connector on the back. This output is driven by the Analog Devices AD9744 digital analog converter. It does have quite some possibilities, as it can generate sines, square, triangle, ramp, Gaussian signals, sin(x)/x, half sinus, and arbitrary waveforms, which means that you can draw any waveform you want. It is also possible to sweep the output signal from one frequency to another, with a certain time step. This feature can be very useful for testing filter responses. The maximum frequency of 20 MHz is common for this kind of equipment.

    When playing with the AWG I found quite some overshoot at steep edges. Which you for instance can see at the 1 kHz square wave pictured below. Channel A (blue) is from a TTI TG2000 signal generator and channel B (red) is the 5444D AWG.

    When decreasing the time interval to 200 ns/div you clearly see the overshoot.

    Which is not seen at the output signal of the TTI function generator.

    Another shortcoming of the signal generator, compared to the TTi function generator is the lack of a digital output. It is even not possible to mimic a digital output, by adding an offset to the signal, as the offset is limited at 1V.

     

    • Topic 4-4: Clock Synchronization

    Clock synchronization can be very useful, as described by Colin O'Flynn of circuit cellar, but this feature is not available on the 5444D.

     

     

    The bottom line

    To finish up this review, in conclusion the 5444D hardware is great, the total feature set is enormous, it outperforms my Tektronix TBS 1202 desktop model. Compared to desktop scopes with the same specs, the price is good. For portable operation the device is very handy, and easy to cary, but a laptop is needed. For on site servicing, you can put the 5444D with a laptop in your bag, which is a big benefit over carrying another bag with your desktop scope. The input range of 20V is a bit limited compared to its competitors, also PicoTech could do better on the quality of the probes.

    Regarding the software, for macOS PicoTech still has some work to do, both on the PicoScope application, as well as on the SDK.

     

    Thanks for reading, and if there are any questions left, please post them in a comment on this review.


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