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PICOSCOPE 5444D MSO -  USB Oscilloscope - Review

Scoring

Product Performed to Expectations: 9
Specifications were sufficient to design with: 10
Demo Software was of good quality: 8
Product was easy to use: 8
Support materials were available: 10
The price to performance ratio was good: 9
TotalScore: 54 / 60
  • RoadTest: PICOSCOPE 5444D MSO - USB Oscilloscope
  • Buy Now
  • Evaluation Type: Test Equipment
  • Was everything in the box required?: No - The package included a copy of the 'USB Data Logger' Quick Start Guide and not a copy of the 'PicoScope USB oscilloscope' Quick Start Guide (available for download), which seemed a little strange.
  • Comparable Products/Other parts you considered: see below Market Survey section
  • What were the biggest problems encountered?: I found the PicoScope 6 software to be somewhat difficult to use and/or understand. The instinctive user experience of using a scope with knobs is completely lost in button icons and, pull downs and screen presentations. But having said that, this is a very capable and useful oscilloscope. The more I used it and consulted the manuals, the more comfortable I became.

  • Detailed Review:

    First off, Thanks! I am extremely grateful to element14 and Pico Technologies for selecting me as a roadtester for the PicoScope 544D MSO.

    This is my first attempt at a roadtest, so I hope that I can successfully manage to inform and rate this instrument fairly.

     

    Market Survey

     

    There are many fine standalone, bench oscilloscopes available.  In the area of 4-channel, mixed signal oscilloscopes here are some of the competitive models:

    Getting this level of performance in a highly mobile format, like the PicoScope 5444D MSO, there are no other comparable devices.  The compact size however, does come with a few disadvantages.  The limited voltage input range of +/- 20 Volts, with 1X probes and/or coax cables is one of those limitations.  Granted, 10X probes give you the ability to get +/-200 volts, but for some people this is not a workable option.  The pricing of the PicoScope 5444D MSO does get very close to the lower end pricing of some standalone oscilloscopes (i.e. Rigol MSO7024).

     

    Unboxing

     

    The shipping package arrived in good shape, with no obvious damage.

    Shipping package

    Removing the packing slip and cutting the tape, reveals the packing materials (simple but effective crumpled paper).

    Packing material

    Digging deeper into the package, below the first layer of crumpled paper,  the actual product box is in view.

    product box in viewproduct box

    With the product box removed from the shipping package, a quick inspection shows the product box has survived the shipping with no apparent damage.  Opening the product box, the PicoScope 5444D MSO is seen carefully cradled in a cardboard surround.

     

    open product box - top of PicoScope 5444D MSOfront panelrear panel

    Removing the upper-level cardboard surround, we can see the lower-level accessory box and the contents below.

    Accessory boxQuick start guideAccessory bagOpen accessory view

    Finally, all of the unboxing is done and here are all the accessories.

    Accessories - Power, USB and Logic probesScope probe packaging

     

     

    Software download (Window 7 example)

     

    The current version of the PicoScope 6 software is available on the Pico Technology website (https://www.picotech.com/downloads ).

    Selecting the Download, the following pop-up appears:

    Selecting the 'Save File' option causes the installer to download.  Once the file (installer) is downloaded, clicking on the downloaded file from within the browser causes Windows to prompt with a 'Security Warning'.

    Install screen

    Accepting the 'Run' option starts the install process which prompts with the Language selection pop-up.

    Language select

    Selecting the default of English (as I am an English speaker/reader), causes the InstallShield Wizard to ask you to 'accept' their license, which allow the install to continue (when you click on 'Install').

    accept

    After a while, the Status Bar appears, and after another while, the process begins.

    Installing.....

    Then Windows will ask if the really wanted to install this program.

    Accept

    Then later in the install, Windows will ask you again to make sure that you really want to load this program (This message appeared a couple of times, until I got tired and just clicked on the 'trust' button).

    Window security

    And finally, the software is installed (did I mention how much I love the Windows install process? )

    Complete

    After connecting up the hardware and doing a little playing around with settings, I was able to attach a scope probe and make a measurement.  I am currently working on a client's project, so I had some interesting signals to look at.  I really like the 'measurements' that you can setup to interpret the signal.  Here we see that the square wave has the following parameters: High pulse width of 19.2us, Frequency of 26.01khz, Duty cycle of 49.94%, with a rise time of 17ns.  This is good news and a great start to seeing what this product can do.

     

    Operation and user experience

     

    As per my roadtest application, here is my plan for testing out the performance and functions of the PicoScope 5444D MSO Oscilloscope.

     

    • User interface and ergonomics - General look and feel of the device and user interface. How easy is it to use?  Are the software/controls easy to understand?  Does it operate like a traditional oscilloscope?

    front and rear panel layoutsDigital input pin mapping.

      • Oscilloscope  - The PicoScope enclosure is solid and well-built.  The rubber protective bezels on the front and back are very nice additions, providing excellent protection for the scope inputs and the waveform/function generator output BNC connectors. The color coded markings on the panels provides a clear indication of the BNC functions.  The white annotations (front and back) were clear, with appropriate warnings shown conveniently.
        • I found the mapping of the Digital inputs to be a little strange.  A better mapping would have placed the D0-D7 lines on one row (with interspersed Grounds) and the D8-D15 lines on the other row.
        • I kind of wished that the waveform/function generator output could have been located on the front panel (I understand the need to minimize the package size and not wanting to over-crowd the front panel).
        • I would have liked to see a ground lug, placed near the probe compensation output to ground the scope probes (I am not entirely sure that scope calibration was effected by a ground connection, little to no change in waveshape with or without the probe being grounded).

    Scope probes side-by-sidePicoScope probe tipTektronix scope probe tip

      • Scope Probes  - I am still not sure how I feel about the scope probes. The ergonomics of the scope probes felt a little 'off' to me. Shown above are a side-by-side comparison of the PicoScope probe (top) and a Tektronix probe (bottom), as well as a comparison of the PicoScope probe tip (center) and the Tektronix probe tip (right).
        • The longer barrel of the PicoScope probe (which the probe hat slides on) seem strangle long and the 'hat' did not slide smoothly along the barrel to expose the hook.
        • The bent wire hook is a little underwhelming. While thicker in diameter (0.022 versus  0.02 for the flat hook), the hook did not do really good at grabbing thin gauges wires (slippage).

     

      • Logic Analyzer clips  - The supplied Logic Analyzer (Digital inputs) clips, connector and wiring were a great addition to the scope.  The mixed colors probes (red for inputs, black for ground), along with the mixed color wires (yellow for inputs, black for ground) were a very nice touch.
        • The quality of the probes felt a little cheap for this nice of a scope.  The plastic felt very cheap and brittle, while the probes did not operate smoothly (very sticky and sometimes refusing to slide at all).
        • The marking on the probe tip connectors were somewhat difficult to read, which along with the strange mapping made it quite difficult to attach the probes to the board under test.  Placing the marking on multiple sides of the connector and/or using color-coded wiring (or connector shells) would have made this a lot clearer.

     

      • Software - PicoScope 6
        • Personal Background - Back in 2007, I started a company to develop a line of USB-based test equipment.  The first project that I had decided to design was a USB Oscilloscope.  A good friend of mine was a former analog design engineer with Tektronics, together with my skills in digital hardware and firmware development, we seemed to have the core skills necessary to take on this project.  The first thing that I do in the beginning of any design is to research the subject and gain as many views as possible to help form my understanding of the potential issues, pit-falls and trends.  The area that concerned me the most was designing the software for a user interface that would allow a user to interact with this oscilloscope in the same way as they would any prior bench top oscilloscope.  Many articles expounded on the virtues of providing an interface that used controls that mimicked knobs and buttons of a conventional instrument as opposed to combo-boxes.  I worked out a couple of examples, but then, as is frequently the case, things changed and the oscilloscope project got shelved. I tried to dig up some of my examples of virtual controls, but too many computer upgrades, disk crashes and physical moves, and I can no longer find any of this work.
        • Initial impressions of PicoScope 6 - I need to preface that I have used PicoScope products in the past, at various companies that I have worked with.  But like a lot of things in the past, the details are very fuzzy.  When I first started poking around this version of the control software, it was like I had never seen any of this before.  I took me a while to stumble through the menus, in order to get a solid waveform to appear on the screen.  Even now, I sometimes fumble around for minutes trying go get the same results I can achieve on my older Tektronix scope in a matter of seconds.  This all feels to me a bit little the PicoScope software has not a done a great job of capturing the 'look and feel' of a normal oscilloscope.
        • Further learning and after a bit of usage and productivity increases.  Also, as some of the more advanced feature of the PicoScope 5444D MSO are exercised, it becomes a little cleared why some of the UI is designed as it is, i.e. there is so much new functionality here that does not exist in more traditional oscilloscopes.

     

    • Specifications validations - Validate accuracy of measurements.  Validate bandwidth and rise/fall times and timebase accuracy.
        • Test setup & explanation - Lacking a high frequency signal/function generator, I will be running a side-by-side comparison of the PicoScope 5444D MSO with my Tektronix TDS 2014B.  I will be measuring signals from a board under development which has a 20MHz oscillator and one of my early versions of my USB scope project with a 40MHz 0scillator.  I am running both scopes with 10x probes with BW limiting turned off.
        • Measuring a 20MHz oscillator output - Side-by-Side results:  PicoScope - rise time = 4 ns, frequency = 20.0 MHz, Vmin = -1.21 V and Vmax = 6.185 V, while the Tektronix - rise time 5.2ns, frequency 19.9998 MHz, Vmin = -1.28 and Vmax = 6.32 V.  The results are very similar, validating input and timebase accuracies (note: closer inspection on the Tektronix rise time measurement look more like a 90%/10% versus the PicoScope 80%/20% test points.  Clearly the PicoScope wins hands down for the larger window and more automatic measurement settings.  Downloading images was also significantly easier on the PicoScope (although I choose PrintScreen to capture the full scope image).

     

    PicoScope 20Mhz measurementTektronix 20MHz risetimeTektronix 20MHz voltage

        • Digging through some my past project boxes, I found a PCB from my old USB scope project that used a 40Mhz oscillator.  I mounted the oscillator and added a few leads to allow me to instrument the part as an addition test point. Measuring a 40MHz oscillator output - Side-by-Side results:  PicoScope - rise time = 7.9 ns, frequency = 40.0 MHz and Vpk-pk = 5.454 V, while the Tektronix - rise time 8ns (this time I mimicked the 80%/20% risetime points) , frequency 39.9998 MHz and Vpk-pk = 5.52V.  The results are very similar, further validating input and timebase accuracies.

    usb scope PCBusb scope PCB zoomed

    PicoScope 40Mhz measurementTektronix 40MHz risetimeTektronix 40MHz voltage

     

    • Triggering Modes- Test and evaluate various trigger modes (auto, repeat, single and rapid) and types (edge, window, pulse width, window pulse width, dropout, window dropout, interval, runt and logic).  Test and evaluate pattern triggers (logic and serial bus)
      • Trigger modes - The real value for capturing waveforms in any of the Trigger modes (except None - which ignores triggering) is in the Trigger types.
        • None - In this mode the PicoScope acquires waveforms repeatedly with out wait for a signal to trigger on.  While this might not be useful to determine timing of waveform detail, it is a good way to get a sense of what the waveform look like in general.  This is a good time to verify the input scaling and timebase (time/division). This a very standard feature, but not on that really requires testing/validation.
        • Auto - The PicoScope will wait for a trigger event (rising/falling edge, etc.) before capturing data, but if no event occurs prior to the timeout it will capture data anyway.
        • Repeat - The PicoScope will wait indefinitely for a trigger event (rising/falling edge, etc.) before capturing data.
        • Single - The PicoScope will wait once for a trigger event (rising/falling edge, etc.) before capturing data, then stops sampling.
        • ETS - Equivalent Time Sampling
      • Trigger types - Here is where all the fun happens.  The PicoScope has several powerful triggers, including some that are a combination of other trigger types.  The usefulness of all of these trigger types will depend on the uniqueness of the signals that you want to capture.  Typically the simple edge trigger is sufficient, but on other signals you may have to try other trigger types to get the capture that you are looking for.

    Trigger types

        • Simple Edge - This is one of the basic trigger types.  Here I am using the Arbitrary/Function generator to generate a signal to trigger on.
          • The Signal generator is setup to produce a 9 MHz Square wave, +/- 2V (I have a small load on the output to eliminate some overshoot, so the amplitude is slightly attenuated).  The trigger is set to Rising edge with a threshold of 0 Volts.  The resulting capture is shown below, with a small yellow diamond (at zero time) showing the trigger event (the Pre-trigger is set to 50%, so the trigger event is centered)

    Simple Edge - rising

          • With the same setup, the edge trigger is set to falling and the resulting capture is shown below.

    Simple Edge - falling

          • Not exactly visible in the two above captures is a small amount of jitter in the waveforms.  The PicoScope has a persistence mode to capture and display multiple overlaid captures to show this jitter.  (note the trigger edge does not vary, only

    Simple Edge - falling - persistence mode

        • Advanced Edge - Advanced edge trigger adds a Hysteresis qualifier to the standard edge trigger to allow triggering of 'noisy' signals.  Here I used the arbitrary waveform generator to create a sin on sin signal to simulate a noisy signal.  Using the Advanced edge trigger I was able to get a solid trigger on the waveform.

    advanced edge triggering setupadvanced edge triggering

        • Window - Window trigger allows to specify a voltage range for the trigger event, such that the scope will trigger when the voltage goes outside of the specified range.  This is useful for catching signals outside the expect norm.  For this example I will use the same waveform used in the Advanced Trigger example to catch a voltage going outside the specified range.

    Window trigger setupWindow trigger

        • Pulse Width - Pluse Width triggering gives the ability to more finely capture a pulse of a specified width.  This is useful when there is jitter in a waveform and you want to select a subset of pulse widths to cause the trigger.  Here is the setup and measured results.  The pulse width specification allows the trigger only to occur when the pulse width is between 50 and 55 nS.  As a result, the centered positive pulse is shown with solid edges, while the remain pulses have shadowed edges, showing the width variances due to the jittered timing.

    pulse width trigger setPulse Width trigger - positive 50-55nS

          • Using the pulse width triggering is also a good way to trigger onto a specific event in a complex serial data stream, especially one with loose timing constraints.  In this example, I am using a DMX512A transmitter (for some background on this interface see shabaz blog DMX Explained; DMX512 and RS-485 Protocol Detail for Lighting Applications.  This is a low end unit, that relies on the PC (Windows) to perform some of the timing aspects (like generating the header of the DMX512 data packet), but due to Windows ability to perform any realtime delays, the preamble pulse are out of specification and very jittery.  Using the PicoScopes pulse width trigger, we can start our capture inside the data portion of the waveform and see stable results.  The first capture is of the overall packet, while the second capture shows the initial data within the DMX payload (512 bytes).  The pulse width settings are being used to capture at the end of the positive pulse (~ 15 mSec wide, prior to the start of the data packet), based on a pulse width between 10 and 20 mSec.

    DMX trigger full packetDMX trigger zoomedDMX trigger settings

        • Interval - Interval triggering is useful in detecting a missing pulse in otherwise repetitive waveform.  Here with the use of the Arbitrary Waveform Generator, I created a signal simulating a missing pulse. In this example the normal cycle time is 100nS, the trigger is set to detect a gap of between 120 nS and 300 nS to trigger on the missing pulse.

    Interval triggering setupInterval triggering

        • Window Pulse Width - This is a combination of Window and Pulse Width triggering, used to detect periods of time that a signal is outside a voltage window.  Here I used the Arbitrary Waveform Generator to generate signal simulating a missing and low voltage level pulse. In this example the normal cycle time is 100nS, the trigger is set to detect a gap of between 120 nS and 200 nS to trigger on the missing pulse.

    Window pulse width triggering setupWindow pulse width triggering

        • Level Dropout - This can be used to detect when a repetitive signal goes high or low and stays in that state for a specified time, or greater. Here I used the Arbitrary Waveform Generator to generate signal simulating a missing pulse. In this example the normal cycle time is 100nS, the trigger is set to detect a low level signal which is greater than 190 nS to trigger on the missing pulse.

    level dropout triggering setuplevel dropout triggering

        • Window Dropout - this mode is a combination of Window and Level Dropout triggers.  It seems that both of those modes were covered well enough.
        • Runt - This trigger that detects a signal that crosses the first threshold, but fails to cross the second threshold.  Here is an example of a runted pulse, using the Arbitrary Waveform Generator.

    Runt triggering setupRunt triggering

        • Digital - Trigger is a combination of multiple digital input channels (MSO only). In this example, I am using an I2C bus to trigger the scope.  SDA is connected to D1, looking for a falling edge and SCL is connected to D0 and looking for a logic high.  This condition is the 'START' signal for a I2C transfer.  I have also connected the A input to the SCL signal and the B input to the SDA to show the I2C signals on the analog side of the scope.  The resulting captures shows a write to address 0x55 with an opcode of 0x64 ('D') and 4 data bytes (each of which are 0x21).  The trigger point (time 0.0) is right at the 'START' signal.
        • Logic - Trigger is the logical process of multiple input channels.  In this example, I am using an I2C bus to trigger the scope.  SDA is connected to D1, looking for a falling edge, SCL is connected to D0 and looking for a logic high and the Logic is set to 'AND'.  This condition is the 'START' signal for a I2C transfer.  I have also connected the A input to the SCL signal and the B input to the SDA to show the I2C signals on the analog side of the scope.  The resulting captures shows a write to address 0x55 with an opcode of 0x64 ('D') and 4 data bytes (each of which are 0x21).  The trigger point (time 0.0) is right at the 'START' signal.

    Logic trigger setupLogic trigger

        • Digital - Trigger is a combination of multiple digital input channels (MSO only). Using the Digital trigger is just like the above Logic Trigger, except the inputs are limited to the digital inputs and the logical condition is 'AND'.

     

    • Waveform Measurements - Test and evaluate some of the many measurement types (AC RMS, true RMS, frequency, cycle time, duty cycle, DC average, rise/fall time, etc.).
      • The Measurement features are quite powerful, allow you to instantly get statistic/metric data based on the selected types.  This sure beats having to use ruler and calculations to get the data that you need.

     

      • Using the setup from the prior measurement (I2C bus), we will zoom in and examine some of the measurement types.  In this example, we have setup measurements of Cycle Time (average of 4 uS), High Pulse Width (average of 1.879 uS), Low Pulse Width (average of 2.558 uS), Frequency( 250 kHz), Fall Time (average of 56.4 nS) and Rise Time (average of 604.9 nS).  The I2C bus is an open collector driver 5 KOhm pull-ups (relatively weak), so the rise times are significantly slower than the fall times.

    measurement types set 1

      • Using the setup from the prior measurement (I2C bus), we will zoom in and examine some more of the measurement types.  In this example, we have setup measurements of Duty Cycle (average of 41.7%), Edge Count (19), Falling Edge Count (10), Rising Edge Count (9), Falling Rate (average of 72.7 V/uS) and Rising Rate (average of 8.143 V/uS).

    measurement types set 2

      • Switching back to the Arbitrary Wave Generator as a signal source, we will examine some of the more analog types of measurements. With a 100 kHz sine wave input, we have setup measurements of AC RMS (average of 711.6 mV), Average DC (average of 1303 uV), Maximum (average of 1.02 V), Minimum (average of -1.02 V), Peak to Peak (average of 2.04 V) and True RMS (average of 7.116 mV).

    measurement types set 3

    • Math functions - Test and evaluate some of the many math functions (the multiple filter types look very interesting).
      • The Math functions are quite amazing.  There are so many functions that it would be extremely difficult to cover all the permutations, so I will cover a few math functions that were interesting to me.
      • One of the things that I have noticed with the PicoScope software is the way that it deals with offsets on the input channels.  I typically think of the offset as just a re-positioning of the zero volt level, but in the PicoScope software the offset is added to the signal channel.  In the following example I will illustrate this issue.  I am using the Waveform generator to generate a 100 kHz, 1.0 V amplitude with an offset of 0.0V signal, which is connected to both the A and B input channels. The input channel A trace is offset by 0.5V (in the A-channel setup menu) to create space between the two traces (so that they are both visible), notice the Maximum Measurement values for the A and B channels (1.514 V and 1.026 V, respectively).  I then used the Math functions to create a Math function of A - 0.5 to remove the offset and added a Maximum Measurement statement for the created Math channel, notice this measurement (1.014 V).  (Note: the Math channel, A - 0.5, which has different values than the A channel is actually superimposed on the A channel, very strange - There is an addition voltage scale and offset for this waveform, but at first I could not tell that it was drawn on the screen).

    Math function 1

      • The Math functions can add a more visual aspect to your debugging.  Here I have instrumented an H-bridge driver that I am developing for a client.  The idea was to show the input to the H-bridge and the resulting enables for the two cross halves of the H-Bridge.  The Input is on channel C (green), while the two halves are on channel A (blue) and channel B (red).  Using a math function I created A-B+C (shown in black), which shows the 'forward on state' as the highest level, 'off time' as the middle level and 'reverse on state' as the lowest level.  Sure you can see this in the normal input channels, but the math function seemed, at least to me, to make the relationships a little clearer.

    Math function 3

      • With the math function visible, I started recommanding some of the parameters to the H-bridge driver to see how this visualization would help to show the motor states, when I began to see some disturbing patterns.  In the first image, I had changed the duty cycle of the input signal from 50% to 60%, which pointed out an error in my pulse timing as the 'forward on state' became uncentered within the input pulse.  I will have to re-visit this logic.  Then I reverted the input duty cycle back to 50% and changed the 'on' times for the forward and reverse cycles, which really caused some strange behaviors (skewed on states and missing reverse on states).  Even more work to do.  I don't normal like finding issues in designs that I believe to be complete, but I was very happy that while roadtesting this scope I found some nasty bugs that I can fix before delivering this prototype to my client.  The true value of test equipment is when it adds value to your debug and development processes.

    Math function 3aMath function 3b

      • Here is a nice math function. Here the Waveform generator is sweeping through frequency (1 kHz to 10kHz in 300 Hz steps every 1 ms).  The Math function is a Low Pass filter of Channel A with a cutoff of 2 kHz)

    Math function 2

    • Spectrum Analyzer - Test and evaluate the FFT measurements and displays.
      • I have typically thought of Spectrum Analyzer as an RF tool, and as such, something that I did not have much need for.  In thinking about ways to utilize this mode, I started thinking about the jitter that I was seeing in some of the Arbitrary Waveform Generator captures that I have done in this road test.  Another way to view the jitter would be to examine it with the spectrum analyzer mode.  In this first test, I used to spectrum analyzer display on a relatively clean signal (5 MHz sinewave) and then a jittery signal (4 MHz sinewave) and compared the differences.  The 5 MHz spectrum is relatively clean, showing a large magnitude at 5 MHz and small peaks at multiples of 5 Mhz (10 MHz, 15 MHz, 20 MHz....), while the 4 MHz spectrum is much noisier, showing a large magnitude at 4 MHz and small peaks at multiples of 1 Mhz (6 MHz, 7 MHz, 8 MHz....).

    Spectrum 5MHzSpectrum 4MHz

    • Protocol decoding - Test and evaluate the trigger and decode aspects of the various protocols (mostly DMX-512, I2C, RS-232/485, etc.).
      • This was one of the features that I was most interested in testing on the PicoScope 5444D MSO.  While not a totally unique feature (available either as a standard or option on most new oscilloscopes), this is a feature that I did not have on my older Tektronix scope (TDS 2014B).  i have used this feature in the past (on older models of the PicoScope at workplaces), so I was excited that this feature was included in this scope.  My primary uses of serial protocols includes both I2C and DMX512A, although I have in the past (and will likely need to in the future) use other protocols.
      • I2C decoding - Here are two examples of Protocol decoding of an I2C bus.  The first capture is of a write sequence followed by a read sequence.  In this capture, the trigger is generated with a Digital pattern trigger with D1 (SDA) set to falling edge and D0 set to a high level, which is the I2C start condition.  The Write sequence (write to slave) consists of an address/command byte (0x55 with write) followed by a data byte of 0x76 (Ascii 'v' for version).  The Read sequence (read from slave) consists of an address/command byte (0x55 with read) followed by a data byte of 0x01 (implying version 0.1, first nibble major rev and second version minor rev).  The second capture is of a multiple byte write sequence.  The write sequence (write to slave) consists of an address/command byte (0x55) followed by 5 bytes of data (0x64, 0x21, 0x21, 0x21, 0x21).  The first byte of the data packet is a command type (0x64 or Ascii 'd') is a driver set command, and data values (0x21, 0x21, 0x21, 0x21) are the desired pulse widths for the driver pulses). Graphical view of the transfer is very nice, allowing you to get a 'big picture view' of the transfer, while the text based decode gives a great overview of the data sent and received.

    I2C write readI2C write

      • DMX512 decoding - I have built a series of DMX512 tools for a couple of different client.  This can be a difficult protocol to visualize as there are potentially wide gaps in the signal which are used for framing and then up to 512 bytes of data being sent at 250 Kbaud.  Trying to isolate a particular byte in side the data stream can be quite difficult.  The PicoScope makes the difficult very possible.  In this example I have a DMX512 transmitter being driven by a PC application.  This application is able to send data to 32 consecutive channels (addressable) in the DMX512 data stream.  The capture that I am interested is where one of the channels is slewing in response to a 'dragging' of the control.  I have set the PicoScope up to use 'Level Dropout' triggering to start the capture at the end of a DMX512 burst.  I have the scope in Single trigger as I don't want to overwrite the data of interest. On my application I command a 'slew to' command by setting up a channel to aggresively filter commands, and then I drag the control pointer from one extreme to the other (this channel is configured to write data into slots 5 and 6).  I try to simultaneously start the PicoScope.  It took a couple of tries, but I was able to catch the moving data.  Extracting the data from the 'Serial Decoding' window (5th and 6th columns of 'Slot Values' entries) and plotting the data with Excel I get the chart to the right.  I so wish I had this capability when I  saw developing these devices and software.

    DMX controlDMX captureDMX data chart

    • Logic Triggers - Test and evaluate the trigger and decode aspects of the logic channels.
      • This is another great feature of the PicoScope.  I have used the logic triggers for some of the I2C captures that I have done.  I will detail more of the trigger setting here.  The first image shows the various 'Start' and 'Stop' conditions for the I2C protocol.  Each of these conditions are unique in the I2C protocol as normal conditions have the data stable when the clock edge occurs.  So triggering is pretty straight forward.  Trigger when D1 (SDA) goes low 'AND' D0 (SCL) is high.  The resulting capture

    I2C specificationsLogic trigger setupLogic trigger

     

    • Arbitrary Waveform Generator - Test and evaluate the function and features of the waveform generator (20Mhz, 32kS, 14 bits), including the standard signals (sine, square, triangle, etc.).
      • This is another great feature of this powerful Oscilloscope.  I used the Arbitrary Waveform to test and demonstrate  a lot of the trigger methods of this roadtest.  Being able to create waveforms within the the built in editor was a real nice feature.
      • The normal waveform were nice and easy to use.  There is a fair amount of jitter present on the higher frequencies (> 1 MHz), unless the divider turns out to be a multiple of the master clock (i.e 4 MHz is clean, 5 MHz is jittery).
      • Being able to import a waveform from a channel and then being able to edit the contents is a great feature. Using this feature, I was able to quickly capture a square wave and then edit out some of the pulse to create stimulus patterns to test many of the different trigger function.
      • Being able to import CSV files into the Arbitrary wave is really a nice feature.  I was able to construct a sine on sine waveform in Excel and then import it.  I used this feature to test the Advanced Trigger feature.

     

    Conclusions

    • The PicoScope 5444D MSO is a very power and useful mixed-signal ocsilloscope.  All of this power within such a small and portable package, makes this a very good oscilloscope for lab and field work.
    • While I started out not being a big fan of the PicoScope 6 software package, I found that with a little reading of the manual, I could make this scope do just about anything.
    • Throughout the process of writing this review, I found myself going back up to the top form and updating the 'Scoring', improving my overall score as I better understood the features and functionality of this instrument.
    • There were a few bugs (or unexplained features) were the scope would randomly quit triggering, but most of these were recoverable by Clicking 'Stop' and then 'Go' to restart the capture process.
    • I know that there are still features and functions of this scope that I have not fully explored.  As I get the time, I will learn more and post update.
    • Finally, Thanks! I am extremely grateful to element14 and Pico Technologies for selecting me as a roadtester for the PicoScope 544D MSO. This is my first attempt at a roadtest and I found this to be an excellent learning and growth experience.  I will enjoy having this scope available to assist in my development and debug efforts.

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