Cursors
Cursors read values off the traces. There are two kinds: one shared vertical pair that
every row carries at the same time, and horizontal rulers, one pair per row, that belong
to that row alone.
How to reach it
The cursors button in the toolbar, or c. The pane below the plot shows the readings and
owns a Reset button. Drag a marker to move it. The mode dropdown offers four modes:
vertical (the shared time pair), horizontal (the per-row rulers),
both, and mix.
Worth knowing
• The vertical pair is one time for the whole figure, so moving it on any row moves it on
all of them. That is what makes dt meaningful across rows.
• A ruler belongs to its row and nothing shares it, so two rows' rulers are independent.
• mix is the reading mode: one line per bound trace, with the trace's own values
at each marker and their difference. A slot with a name but no channel behind it is not a
trace and gets no line.
• A value is the nearest stored sample's, never a number between two samples. Zoom in past
the sample spacing and the line between two samples is something the plot drew, not data —
so a reading off it would be the drawing. The hover crosshair reads the same way.
• Every reading carries a metric prefix so the digits sit in 1..999:
10.52 mV, not 0.01 V. Two decimals is all an instrument landing on an
f32 sample can claim, so without the prefix a small value would read 0.00
and the reading would be gone. A stream that declares no unit gets the prefix anyway, written
tight against the number (585.24m) — the space separates the number from its unit,
and a spaced m with nothing after it would read as metres.
• A marker past the newest sample reads --. With only one marker over data the row
reads partial: a difference between a number and nothing is not a number.
• In mix each marker also places a crossing annotation per trace, which is what lets
you see on the plot which sample a number came from. It is on that sample, so when the
marker falls between two it sits a little off its own line: the line is where you put the
marker, the dot is the datum being quoted. The hover crosshair's mark snaps the same way, and
is drawn larger than a trace's sample dots so it does not read as one more sample.
• The time row exists only in the modes that show the vertical pair. horizontal has no
time row, by design.
• A cursor stays where you put it while a live view rolls under it, which is what a bench
scope does: its T0 is an age, so a marker left at -1.5s keeps reading the
sample a second and a half old as the stream advances. A measurement's marks do the opposite —
they travel with the sample they measured — because a cursor is a question you asked and a mark
is an answer about one particular sample.
Example
Three traces in mix mode with both markers over data: 3 lines and 6 crossing marks,
each line reading like sine 0.31 V -0.84 V -1.15 V. Move the second marker past the
newest sample and the third column reads --.