Fluke 8588A Operator's Manual page 114

8588A/8558A
Operators Manual
An example of using Count would be if you need to capture and plot a burst of
100 points on an input wave form. With Triggers/Arms (Count) set to 100, push
 to put the Trigger subsystem into Idle. Push . The Trigger Loop
Counter is incremented to one on the first pass. In the upward pass the Trigger
Loop Counter value is compared with the Count setting. The process remains in
the Trigger layer until the Loop Count reaches the Count setting. When Loop
Count reaches Count (and 100 readings are made), the process exits the Trigger
layer, returning back to the Initiate layer.
Details of the Trigger subsystem in this example: After you push , the
triggering process leaves the Initiate layer, passes through the two ARM layers
(which are each set to Immediate by default) and enters the Trigger layer. As the
event is set to Immediate (default), there is no need for a discrete Event to occur
and the process moves downwards to start an acquisition. The Trigger Loop
Counter is incremented on the way down. In the upward pass the Trigger Loop
Counter value is compared with the Count setting. The process remains in the
Trigger layer until the Loop Count reaches the Count setting. When Loop Count
reaches Count, the process exits the Trigger layer upwards, through ARM1 and
ARM2 to the Initiate layer. The system remains in Idle until  is pushed
again.
Triggers/reading (ECount): The default for Event Count (ECount) is one.
ECount determines how many trigger events are required to cause one reading
to be taken.
An example of using ECount would be if you need to trigger accurately at a
2 MHz rate when digitizing. You use a 10 MHz off-air-standard to provide an
accurate frequency source. The external trigger signal must be divided by 5 to
achieve the desired 2 MHz rate. Set ECount to 5. Set Trigger Event to External.
Set edge type to TTL Negative (or Positive), and apply the 10 MHz signal to the
rear panel TRIG IN BNC. The Product now makes readings at a 2 MHz rate (with
a 500 ns interval), making readings on every fifth conforming trigger edge.
Details of the Trigger subsystem in this example: When a conforming event is
detected, in this case TTL pulses, the Trigger Event counter is incremented. If
the Trigger Event Count is less than ECount, the process flow loops back to the
event detector. Looping continues until the Trigger Event Counter equals ECount
when the process flow continues down to trigger an acquisition.
Delay: This is the time to wait after a trigger event before initiating the
acquisition. The default setting of AUTO sets a delay sufficient to allow the
measurement circuit to settle for that function and range, and after a
configuration change. The automatic delay is variable and Product configuration
dependent. Delay can be manually set for a fixed time of 30 ns to
4,000,000 seconds. Resolution is 10 ns for delays up to 40 seconds.
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