A to Z of PicoScope

A

Alarms are actions that can be set up to execute when selected events occur, with your PicoScope providing automatic functions. Alarms can be triggered when the PicoScope has captured a complete waveform or a block of waveforms, or when a signal strays outside the expected pattern as defined by PicoScope’s flexible Mask functions.

When one of these conditions is detected, PicoScope can beep, play a sound, save the buffer or all buffers, restart or stop the capture, or run a program of your choice. This way the PicoScope can also trigger external equipment.

Also called DC offset. This valuable feature can give you back the vertical resolution that would otherwise be lost when measuring small signals.

Analog offset adds a DC voltage to the input signal, allowing a more sensitive range to be used if the signal would otherwise be out of range of the scope’s analog-to-digital converter (ADC); effectively allowing you to magnify a small section of the signal.

Attenuator

An attenuator is an electronic device that reduces the power of a signal without distorting its waveform.

The Pico Technology TA197 is a passive 10:1 attenuator. This means that a 10 V signal at its input will appear as a 1 V signal on the output. Attach one to a PicoScope and you can measure signals up to ±400 V without damaging the scope.

>> More information on the TA197

The Automotive Guided Tests are invaluable for new users, but sometimes you start changing the setup of the scope or need to configure it from scratch. Whether you are looking to just get back to something sensible on the display, or don’t know what the signal characteristics are, Auto Setup will figure it out. When you press the "lightning" button on the Setup toolbar, PicoScope searches for a signal on one of the enabled input channels, then sets up the timebase and signal range to display the signal correctly.

If you have added a few input channels, maybe some reference channels and have enabled math channels, it can take time to move them around and scale them so that they are all clearly visible. Auto-Arrange Axes is activated by right-clicking on a view; all the traces are automatically positioned and scaled so that none of them overlap.

B

Battery, starter and alternator test

Did you know that your PicoScope also can operate as a highly accurate and efficient battery and charging circuit tester? This allows you to test your customers' vehicles without the need for dedicated, expensive test tools.

Using PicoDiagnostics, you can check the battery, starter, alternator, and wiring, all in one quick test. Easy-to-understand reports with red, amber or green indicators can be printed for customers, either to show the electrical system is in good condition, or to explain why a component needs replacing.

The battery test checks the state of charge, the voltage drop during starting, and compares the cold cranking amps (CCA) with the rating for the battery. 

The charging test checks the alternator is correctly charging the battery and spots problems, such as overcharging or excessive ripple due to a blown diode.

The starter test helps identify a failing starter motor by measuring its coil resistance. 

The drop test measures the voltage drop (and resistance) of the cables running from the battery to the starter motor. This will discover starting issues caused by corroded or damaged battery cables, or poor connections to the chassis ground. 

Once your test is completed, you can print out a copy of the report for your customer. This report is fully customizable with your own company details and logo to give a professional appearance.

C

Compression test

Check for mechanical issues in seconds: Simply clip the test leads to the battery and crank the engine. The relative compression of each cylinder is shown in an easy-to-understand bar graph format.

To show absolute compression, add an optional pressure transducer to one cylinder, and the software will calculate the pressure for all cylinders in bar or PSI.

ConnectDetect®

Making sure that you have a good connection to the signal you want to test is not always easy. With ConnectDetect enabled, indicators on screen, and lights on the scope itself, turn from red to green as soon as a good connection is detected.

Once a good connection is established, the on-screen icons fade so as not to obscure the waveform. If, however, the status changes (for example vibration causes a probe to become loose), the icons will highlight the change.

Cylinder balance / misfire detect

Check for misfires, and check if each cylinder is contributing the same amount of power, with the cylinder balance test.

Simply connect channel A of the PicoScope to the vehicle battery and start the engine. The software detects changes in engine speed as each cylinder fires. An easy-to-understand bar graph display shows the relative power output from each cylinder.

Please note: this test will not work correctly on certain vehicles that disable cylinders for emissions control reasons, or on low-compression engines with 8 or more cylinders.

D

PicoScope Automotive oscilloscopes have waveform buffer sizes of up to 250 million samples – many times larger than competing scopes. Most other scopes with large buffers slow down when trying to use a lot of memory, so you have to manually adjust the buffer size to suit each application. You do not have to worry about this with PicoScope deep-memory scopes, as hardware acceleration ensures you can always use deep memory while displaying at full speed.

Deep memory produces several benefits: fast sampling at long timebases, timebase zoom, and memory segmentation to let you capture a sequence of events.

Many automotive oscilloscopes still use an analog trigger system based on comparators. This causes time and amplitude errors that cannot always be calibrated out, and that often limits the trigger sensitivity at high bandwidths.

Pico pioneered the use of fully digital triggering using the actual digitized data. This technique reduces trigger errors and allows PicoScopes to trigger on the smallest signals, even at the full bandwidth. Trigger levels and hysteresis can be set with high precision and resolution; and PicoScope's digital triggering, together with an optimized memory system, allows the capture of events that happen in rapid sequence. 

Some digital automotive oscilloscopes only provide triggering in software, which means that you can sometimes never actually see the event you were hoping to use as a trigger.

PicoScope software is designed to make the best use of your display area, maximizing the waveform size. This makes sure that you see as much information as possible, in outstanding detail. With a PC or laptop, the viewing area is bigger and in higher resolution than any handheld tool, allowing you to make use of PicoScope’s flexible split-screen capability. As the example shows, PicoScope software can show multiple waveforms, each with its own individual zoom, pan, and filter settings for ultimate flexibility.

E

Electric vehicles also require diagnosis and repair, but there are a few major differences that affect the technician's work. Although the powertrain is completely different, so you certainly don’t need to worry about ignition timing, there are a host of convenience, safety, entertainment, handling and interior functions that are just the same as on any other advanced vehicle.

First of all, PicoScope is set up to provide rapid analysis of body and chassis systems, including motor and lighting currents.

The additional complication with both hybrid and electric vehicles is the need for safety testing – you want to be sure that there is no high voltage present before starting to work on the vehicle. After any repairs, and for general safety, it is also advised to check for insulation resistance before restoring high-voltage systems, to make sure that the system is in good condition. If you need a solution for HEV Safety testing, please contact Pico for further details.

PicoScope is the tool chosen by Tesla Motors and some of the world’s other leading developers and manufacturers of electric and hybrid vehicles. They know the benefits PicoScope can deliver on customer satisfaction and cost, through improved "fix it right first time" results.

F

FlexRay

Automotive PicoScopes are fast enough to display FlexRay signals accurately. FlexRay is a vehicle data bus standard used in active suspension systems. Its high speed means that the signal quality is critical, and only a fast scope can reveal problems like reflections and ringing.

We recommend using the 60 MHz Oscilloscope Probe for connecting to FlexRay signals, to make sure you have minimal distortion. This probe is included in PicoScope Advanced Diagnostic Kits.

G

PicoScope guided tests

There are over 150 guided tests, ranging from simple injector tests through to more complex topics such as CAN bus testing, integrated into the software.

When you select a guided test all settings are configured for you, and an example waveform is loaded. Diagrams and photos then show you the leads and accessories you need, how to connect to the vehicle, and how to perform the test.

Once the test has been completed you will find guidance on understanding the waveform, how the component works, and typical faults/fixes.

As vehicle technology changes we continue to add more tests through the free software updates. 

Browse the library of guided tests >>

H

Hall effect

The Hall effect sensor is commonly used in camshaft and crankshaft position sensors, but can also be found in other applications, such as ABS sensors.

Hall effect sensors use the principle of a magnetic field, diverting the electrons in a semiconductor in a direction perpendicular from their usual path. These electrons create a potential difference, called the Hall voltage, across the semiconductor.

A Hall effect sensor is used in conjunction with a permanent magnet. By interrupting the field of this magnet with a metal disk fitted with blades or windows, pulses of Hall voltage are produced which are output by the camshaft or crankshaft sensor.

PicoScope displays the Hall voltage pulses as a square wave, thereby reproducing the signals received by the camshaft and crankshaft position sensors.

I

Intermittent problems are hated by both customers and technicians, causing frustration, loss of time, repeat visits, and potentially expensive parts swapping in an attempt to eliminate the problem by educated guessing.

Before swapping parts, one of our valued training partners offers the following advice. "Imagine that the part(s) you are swapping don't fix the problem; what would you do next? Now do that before you change the part(s)."

PicoScope has a wealth of features included in the design from the start. This way it can better equip you in the fight against intermittent problems. For more information, please read this application note full of details on what PicoScope offers.

J

Don’t know your BCM from your ECM, or your CAN from your LIN? You’re not alone. Click on this link to see the list of some of the popular abbreviations that are used in automotive diagnostics: https://www.picoauto.com/library/jargon-buster

JCASE fuse

JCASE is a cartridge-style fuse with female terminal design, providing both increased time delay and low voltage drop to protect high-current circuits and handle inrush currents.

For testing JCASE fuse currents, use the JCASE fuse extension lead. Compatible with standard and low profile JCASE fuses, this fits between the fuse and the fuse holder and gives you a loop of wire on which to place a current clamp.

K

PicoScope software provides a set of default and advanced keyboard shortcuts (called a map) that provide access to common functions. You can create your own maps, and can also import/export maps for loading onto another PC in case you use your PicoScope with more than one computer.

L

LIN (Local Interconnect Network) is a serial protocol used in automotive electronics to allow microcontrollers to communicate with low-speed peripherals. The standard was defined by the LIN Consortium, a group of five vehicle manufacturers. It uses a single wire pair with a master-slave topology, offering lower cost, reliability and data rates than CAN – hence its use in non-critical, low-speed applications.

Examples of LIN might include commands from a comfort control unit to an electric sunroof motor, windscreen wiper or heater motor functions. 

PicoScope's serial decoding feature can decode LIN bus messages.

M

Memory buffer

The best way to diagnose an intermittent fault is often to set up the scope to measure from several components and wait for the fault to occur. For an intermittent misfire, you might want to capture several minutes of cam, crank, ignition and injector waveforms. These types of tests require an oscilloscope with a "deep" memory buffer, so that you can capture for long periods of time and then zoom in without any gaps or loss of detail.

With PicoScope you can collect 250 MILLION samples, more than any other automotive oscilloscope. Our advanced "always on" memory technology uses hardware acceleration to make sure that the processing of large amounts of data does not slow the oscilloscope down even when you are using a slower or older PC.

Deep memory allows long recordings at high speed – you capture a complete test drive whilst looking for intermittent faults. When not using the full memory for a single waveform, PicoScope automatically stores up to the last 10,000 waveforms in the buffer, so you can stop the scope and “wind back time” to see every capture.

N

Noise and vibration kit (optional)

Improvements in damping and sound insulation in modern vehicles mean that vibrations and noise that would previously be ignored (by turning up the radio) are now diagnostic headaches. Many hours can be spent, and many parts swapped, in tracking down customer complaints.

The NVH kit works with your PicoScope to quickly identify the source of the problem. If the customer complaint is noise, use the microphone; if it’s a vibration, use the accelerometer. Sophisticated software quickly pinpoints the source of the problem.

The kit can be enhanced with accessories to also allow on-vehicle driveline balancing.

More information on the NVH kit >>

O

P

PicoDiagnostics

With a simple connection to the battery, the PicoDiagnostics software quickly performs the following tests:

  • Compression test. Crank the engine to quickly display the relative compression of each cylinder.
  • Cylinder balance / misfire detect. Compares the power output of each cylinder and highlights misfires.
  • Battery test. Displays CCA, measures state of charge and voltage drop during starting. Gives an overall Pass or Fail.
  • Starter motor test.  Checks starter coil resistance and voltage drop across cables.
  • Alternator test.  Measures charging voltage and current. Checks for excessive diode ripple.

More information on PicoDiagnostics >>

PicoScope 6 Automotive

PicoScope Automotive is a powerful software package that turns your PC into a Diagnostic Oscilloscope when used with a PicoScope device. PicoScope has been designed to make it easy to diagnose vehicle faults. Packed with features such as automated measurements and the ability to save and print waveforms, PicoScope Automotive is the ultimate tool for any diagnostic toolbox.

Updates to PicoScope 6 Automotive Beta: 6.12

Improved UI:

  • Larger control buttons for improved touchscreen instrument control.
  • Addition of Increase and Decrease buttons for easier control of primary oscilloscope functions.
  • Addition of control settings grids for faster control of primary oscilloscope functions.

New feature:

  • Edge measurement

More information on PicoScope – Latest updates >>

Q

R

Rotation rulers

PicoScope can draw Rotation Rulers on a waveform to indicate rotation angles of the crankshaft or camshaft. This feature is particularly useful for analyzing compression waveforms on a four-stroke engine.

  1. Capture your waveform (or load a previously captured one from disk).
  2. Drag the green dot (the rotation ruler handle) to the start of your waveform. This represents 0°.
  3. Drag the second green dot to the end of your waveform. This will usually be 720° for a four-stroke engine.
  4. Set the Partitions control to 4 and PicoScope will then automatically divide the waveform into four equal partitions, representing the four strokes of the engine cycle.
  5. PicoScope will display measurements in rotation angles (or any other rotation units that you choose.)

Time rulers

The time rulers measure time on a scope view. In the scope view, the small white squares on the time axis are the time ruler handles. When you drag these to the right from the bottom left corner, vertical dashed lines called time rulers appear.

At the same time the Ruler legend will appear. This shows the position of any time rulers that are in use. If there are two time rulers, it will also display the difference between them. Clicking the Close button on the ruler legend deletes all the rulers.

S

Samples

Samples are best explained when we think back to the days of creating a line graph on graph paper. You would take your data, and count along the x and y axis in order to mark a point, before moving on and making another, and another and another. You would then draw lines between these points to make your line graph.

These points are called samples (the lines you drew are how the oscilloscope draws the waveform between these samples).

Sampling rate

Leading on from our Samples information, sampling rate is simply how many samples will be taken per second. This setting is important when you think about the amount of data you wish to collect, and over what time period.

For a slowly changing signal requiring a longer recording time, use a low sampling rate. For a fast-changing signal over a short time period, use a high sampling rate.

The sampling rate is controlled by the Number of Samples setting in the PicoScope software. Here you tell the software how many samples you wish to collect across your capture. The actual sampling rate (X S/s) can be seen in the Properties panel (Views > View Properties).

When choosing a sampling rate, you must consider the timebase you are capturing over and the memory of your scope (our latest automotive scopes all come with a 250 million sample memory).

Serial protocols are on every modern vehicle, and increasingly there will be multiple serial data buses on every vehicle. Some of those will be present on the J1962 (often known as OBD, EOBD or simply 16-pin) connector for communication with serial diagnostic (or scan) tools. Many will be private and vital for the internal operation of the vehicle and essential systems.

PicoScope includes a special feature for decoding the serial protocols, together with standard voltage based testing to reveal problems like noise, poor levels, unbalanced differential signals and a host of intermittent problems. 

The common protocols found on modern vehicles are CAN, LIN and FlexRay, with the impending deployment of a new SENT protocol that provides digital data directly from sensors to ECUs.

PicoScope includes as standard decoding of all the above protocols and can reveal timing, bus contention and bus hogging by misbehaving ECUs. When the car is on the coverage list, but your serial diagnostic tool cannot even talk to it, have your PicoScope handy to check that all is as it should be.

T

Timebase

To select your desired timebase simply click on the Collection Time drop-down and select it (here we will use 20 ms/div).

The waveform capture area is split into 10 horizontal divisions now each with a value of 20 ms, meaning your total waveform capture time (timebase) is 200 ms.

20 ms/div is chosen as the general timebase setting to enable the scope to capture all events that take place during a 4 stroke cycle on one screen. This will ensure you miss nothing from injection to ignition events. Two valuable points to remember here are:  The four stroke cycle takes 150 ms to complete at 800 rpm and 1 second is equal to 1000 milliseconds.

To view more detail of a single event, reduce the timebase. To view more events with less detail, increase the timebase.

Training

PicoScope is easy to use, but not everyone uses it all day and every day. To help both new users, and as a reminder for experienced technicians, Pico offers a wide range of training materials and training partners.

Training manuals, videos and other resources are available in our library (just select the library on the top level tabs).

In the training section you will also see details about Pico trainers in various markets. Any of our distributors can provide (or arrange) training, so please also contact them directly.

Visit our documents section, or view the case studies for even more heplful information and tips.

If you have any problems, please email support@picotech.com

Trigger

A trigger ensures that the scope captures the waveform at the right time and keeps the waveform in a stable position on your screen. PicoScope usually sets up the trigger automatically once activated, but you can adjust the settings and the trigger mode in order to capture those unusual waveforms you might otherwise miss.

U

Many oscilloscopes can appear to have adequate specifications on paper, and it easier to polish a website description than it is to design a great scope from the ground up.

An key specification that is often omitted by some manufacturers is the waveform update rate, expressed as waveforms per second (wfms/s). This indicates how quickly an oscilloscope acquires waveforms.

PicoScope Automotive Oscilloscopes use deep memory and hardware acceleration to achieve over 100,000 wfms/s to better capture signal behavior and dramatically increase the ability of the oscilloscope to quickly capture intermittent problems such as jitter, runt pulses and glitches – problems that you may not even know exist when using an inferior product.

USB 3.0 for power, speed and simplicity

As with our previous generations of PicoScope oscilloscopes, no external power supply is required and there are no batteries to go flat, just a simple reliable connection to the USB port.

The PicoScope 4225 and 4425 have the latest SuperSpeed USB 3.0 port to interface to your PC. Don't worry if your PC only has USB 2.0 ports – the PicoScopes are fully compatible with these too. If you have USB 3.0 on your PC you will notice slightly faster screen update rates, faster file saving and USB streaming. As more of our customers move to PCs with USB 3.0, free software updates will ensure that you get the full benefits available from the new standard.

Our unique fast USB streaming allows continuous gap-free data to be collected straight to PC memory. This makes features like our cylinder balance, battery test and (optional) NVH tests possible. It also allows the oscilloscope to display live, real-time data without waiting for the screen to refresh.

V

Vibration is any oscillation (regular movement) that is felt or seen by the vehicle occupants. Vibrations have low frequencies, below 200 Hz.

The PicoDiagnostics NVH System analyzes and diagnoses problems with Noise, Vibration & Harshness (NVH) that can be very difficult to isolate without specific tools.

Vibrations can be subjective, but the Pico NVH system provides objective results and can provide you with customer reports for 'before' and 'after' any fixes.

W

One of the hardest problems to diagnose is the intermittent fault – it may be a customer complaint or may even have triggered a fault code, but it never appears when you are looking. With PicoScope you don’t need to worry about missing glitches or other transient events as the software can store the last ten thousand waveforms in its circular waveform buffer.

Used with triggers or mask limit testing, your PicoScope can be configured to save everything leading up to and following that intermittent event in the waveform buffer. PicoScope can also be set up with alarms to beep or send you an email to let you know when it has found the problem.

The buffer navigator is how PicoScope lets you navigate and search through waveforms effectively letting you turn back time.  Mask limit testing can also be used to scan through each waveform in the buffer looking for mask violations and providing instant visual identification of the problem area.

Waveform library

The library enables you to share and back up your waveforms online and also search a global database of waveforms uploaded by PicoScope users from around the world.

The powerful search options let you find “known good” waveforms from vehicles identical to the one you are working on. Not sure if you have a slipped timing belt? There are hundreds of cam vs crank waveforms to compare against. Not sure if the cranking current is too high? Download a waveform to compare.

More information on the waveform library >>

X

Y

Z

The PicoScope Diagnostic Oscilloscopes have a deep buffer memory, which allows them to provide high sampling rates across long timebases. For example, with a 250 MS buffer the PicoScope 4425 can sample at 100MS/s on 4 channels all the way down to 50 ms/div to give a total capture time of 500 ms. The zoom and scroll functions enable you to navigate and display all the data in detail. The zoom overview shows you the full waveforms on all channels, and allows you to easily control the zoom area by just clicking and dragging.