User manual

PicoScope and oscilloscope primer30

5.23

Mask limit testing

Mask limit testing is a feature that tells you when a waveform or spectrum goes

outside a specified area, called a mask, drawn on the scope view or spectrum view.

PicoScope can draw the mask automatically by tracing a captured waveform, or you

can draw it manually. Mask limit testing is useful for spotting intermittent errors

during debugging, and for finding faulty units during production testing.

To begin, go to the main PicoScope menu and select Tools > Masks > Add Masks.

This opens the Mask Library dialog. When you have selected, loaded or created a

mask, the scope view will appear as follows:

(A) Mask

Shows the allowed area (in white) and the disallowed

area (in blue). Right-clicking the mask area and

selecting the Edit Mask command takes you to the

Edit Mask dialog. You can change the mask colors

with the Tools > Preferences > Colors dialog; add,

remove and save masks using the Masks menu; and

hide and display masks using the Views > Masks

menu.

(B) Failed waveforms

If the waveform enters the disallowed area, it is

counted as a failure. The part of the waveform that

caused the failure is highlighted, and persists on the

display until the capture is restarted.

The number of failures since the start of the current

scope run is shown in the Measurements table. You

can clear the failure count by stopping and restarting

the capture using the Start/Stop button. The

measurements table can display other measurements

at the same time as the mask failure count.