Connecting An External Trigger; Monitoring The Measurement-Complete Signal - Fluke 8845A User Manual

8845A/8846A
Users Manual
1. Press Lto display the measurement setup menu.
2. Press the TRIGGER soft key.
3. Press the soft key labeled #SAMPLES.
4. Use the soft keys to set the number of samples between 1 and 50,000.
5. Press ENTER.

Connecting an External Trigger

The TRIG I/O jack on the Meter's rear panel is used to connect to an external trigger
signal. The falling edge of a TTL signal will trigger the Meter to start taking
measurements, if the Meter is in external trigger mode.
Figure 4-9 indicates the purpose of the three pins in the TRIG I/O connector.

Monitoring the Measurement-Complete Signal

In addition to being a trigger input, the TRIG I/O jack on the Meter's rear panel also
provides a signal indicating the completion of a measurement cycle. A falling edge of a
TTL signal indicates a measurement cycle is complete. See Figure 4-9 above to identify
which pins on the TRIG I/O connector are used to sense the measurement-complete
signal.
4-18
Select the digit in the value by pressing either <-- or -->.
With the digit selected, press the soft key labeled -- to decrement the digit or ++ to
increment the character.
Pin 1: Trigger In
Figure 4-9. TRIG I/O Pin-out Description
TRIG I/O
Pin 3: Measure Complete Out
Pin 2: Signal Ground
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