Welcome to Snap-on Training Solutions. This module is designed to help you get the most out of your MODIS Ultra diagnostic tool, and covers the use of the digital and graphing meter and lab scope.
Meter Test Functions
The multimeter and lab scope are powerful diagnostic tools that give you the ability to display precision measurements of electrical signals. In automotive applications this is typically the final step to verify a failed component with certainty before replacing it.
The Scope Multimeter icon accesses the Lab scope, Graphing multimeter and Digital multimeter. Let’s select digital meter to explore the capabilities.
The meter includes tools for a variety of automotive applications. Never attempt to measure more than the meter’s rated capacity.
Most test connections are made with these meter leads. One for positive and one for negative.
Digital Multimeter
The digital meter displays a single value at a time. This is most useful when the value is not rapidly changing.
To perform an Ohm or amp measurement, the first step is to calibrate the meter to insure accurate results.
Simply follow the onscreen calibration instructions. The display will show zero ohms when the leads are connected together. When the leads are separated, the four arrows indicate infinite ohms and an open circuit.
Graphing Multimeter
The Graphing meter is useful to see how a value changes over time, and can reveal how a component functions, or malfunctions under varying conditions. The graphing meter navigation shown here is similar for the lab scope, but the lab scope can capture very high speed signals with up to six million data samples per second.
You can select from over twenty graphing meter tests and display options, including Dual Graphing Meter, Volts DC, Volts AC, Frequency, Pulse width, Duty cycle and Dwell.
Specialized scales for optional probes can accurately graph changes and glitches in pressure, vacuum and temperature in a wide variety of automotive applications. Current measurements require the optional precision low amp probe. This is especially useful for finding parasitic loads, faulty injectors, pumps and relays. Contact your Snap-on Franchisee to add these handy accessories to your tool.
Let’s select volts DC to graph voltage change over time.
Here a constant voltage signal appears as a flat line, with no variation or glitches over time.
We can easily capture glitches and dropouts to detect wiring issues, failing components and intermittent problems. The meter continuously records up to 262 screens of data for review. This makes it easy to perform a road test or a wiggle test without having to watch the meter. Pressing the red stop icon freezes the data recording so you can review it.
Use the double arrow icons to scroll one screen at a time. Use the single arrow icons to scroll one data point at a time.
Or slide this scroll bar forward and back to quickly access all recorded data.
Customize the meter display with these setup tools. The profile icons choose which channels to display. Touch once to display a channel, and again to hide it. To move a channel up or down the scale for easier viewing, touch channel marker and slide up or down.
With two channels activated, the graphing meter or the scope can show relationships between component functions like these two oxygen sensor signals. Or compare two similar components to detect one that is failing.
The probe menu gives you control over the type of test used on each channel, such as volts, dwell, pulse width, frequency, duty cycle, pressure vacuum and amps.
6 Million Data Samples per Second
At six million data samples per second, the Snap-on scope function can capture many more samples than displayed on most standard display screens.
To take advantage of this capability, select the peak detect function. The scope samples at the maximum rate possible and captures extremely fast peaks and glitches, like this ignition spike.
Coupling AC subtracts the average value of a signal so that small variations display prominently on the waveform. This blocks the DC portion of the signal to amplify the AC signal without driving the waveform off of the screen. Simply touch the Coupling AC icon to activate.
The scope trigger sets a threshold value that initiates the waveform display. When the voltage passes the threshold value, a new waveform begins. This produces a very stable waveform that does not flicker or drift. Touch the trigger icon to trigger when the voltage rises to the threshold value. Touch the icon again to trigger when the voltage falls to the threshold value. The trigger point appears as a plus sign on the display. Touch and drag the plus sign to position it. Or touch the large plus sign on the control panel to use the four-way control for a more precise setting.
Easily change the time scale or sweep using the sweep menu. You can set the total time it takes for the data to fill the screen, anywhere from 1 to 20 seconds in meter mode and as short as fifty microseconds in lab scope mode.
Touch the scale value to change it anytime with this popup menu. After making a menu selection, simply touch a blank spot on the screen to hide the menu.
The graphing meter also tracks the minimum and maximum recorded values. Selecting the refresh icon clears these values and the tracking starts over.
To see more detail at any time, touch the full screen arrow to hide the control panel and expand the graphing display. Touch it again to show the control panel.