ADLINK cPCI-9116 User Manual

Page 55

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Operation Theory

• 45

Delay Trigger Acquisition

Use delay trigger acquisition in applications where you want to delay the data
collection after the occurrence of a specified trigger event. The delay time is
controlled by the value, which is pre-loaded in the Delay_counter (16bit). The
counter counts down on the rising edge of Delay_counter clock source after
the trigger condition is met. The clock source can be software programmed
either Timebase clock (24MHz) or A/D sampling clock (Timebase
/SI2_counter). When the count reaches 0, the counter stops and 9116 card
starts to acquire data. The total acquired data length = DIV_counter *
SC_counter.

(DIV_Counter=4, SC_Counter=3)

Acquisition_in_progress

Scan_start

AD_conversion

Scan_in_progress
(SSH_OUT)

Acquired & stored data
(3 scans)

Operation start

ExtTrg

Delay until
Delay_Counter
reaches 0

Figure 17: Delay trigger

Note:

When the Delay_counter clock source is set to Timebase, the maximum
delay time = 2

16

/24M s = 2.73ms, and when the source is set to A/D

sampling clock, the maximum delay time = 2

16

* SI2_counter / 24M).

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