Fluke PM3370B Trigger Mode Triggered, 36HOW to USE the Instrument, Press the TB Mode key

4 - 36HOW TO USE THE INSTRUMENT

TRIGGER MODE TRIGGERED

-Press the TB MODE key.

TB MODE

In the screen, the timebase mode (TB MODE) menu appears. ’auto’ is intensified. With the "auto" mode turned on, the timebase will run free as soon as no triggering signal is detected, in order to provide a base line. The ’Auto’ mode works well with most signal that have frequencies of 30 Hz or higher.

-Press the softkey next to the ’auto trig single’ function to select ’trig’.

In the triggered mode, a signal is visible only when proper triggering occurs.

-Move the indicator (T-) in and out of the signal range.

T−

TRIGGER

LEVEL

T−

ST6737

In the Analog mode, the result is a stable and triggered signal when the indicator is inside the signal range, and no trace appears on the screen when the indicator is outside the signal range.

Disabling the ’auto’ function by selecting ’trig’ can be useful for displaying very low frequency signals. The scope waits for a real trigger before the sweep starts even if the signal frequency is very low.

In the Digital mode, the same criteria exist for the use of the ’auto’ function and the ’trig’ function, but there is a difference. When the scope is in the ’trig’ mode and triggering is lost, the acquisition will stop, but the display will reflect the last information before the triggering stopped. This may lead you into thinking that the scope is properly triggered because the display appears to be stable, while in fact, you are displaying stored information only. Watch the ARM’D LED !