Keysight DAQ970A Guia Del Usuario página 158

3 Features and Functions
Source Level
Selects level trigger. The instrument is triggered when the specified measurement threshold condition is met.
– You may press the Ext Trig softkey to specify the polarity of the Ext Trig signal as rising edge (Pos) or falling
– You may also press the PreTrigger Count softkey to specify a pretrigger count between 0 to 999,999.
After specifying a pretrigger count, readings are taken and held in a buffer while waiting for the trigger event
to occur. When the trigger event occurs, the buffered readings are transferred to reading memory and the
remaining readings are recorded as usual. If the trigger event occurs before Pretrigger Count readings have
been taken, the trigger event will still take effect and digitizing will complete without having taken all of the
pretrigger readings.
The Pretrigger Count is limited to one less than the total number of readings specified to be taken by the
Sample Count setting. If Sample Count = 1, the Pretrigger softkey will be hidden.
Specifying the Sample Timer
Softkey Description
Sample Use the knob or arrow key to specify the sample timer (time between samples) between
Timer 20 μs to 3600 s.
This configured value for Sample Timer will remain even though you have changed the channel's measurement
function in the [Channel] menu.
Specifying the Sample Count
Softkey Description
Sample Use the knob or arrow key to specify the total number of samples to digitize between 1 sample up to a
Count maximum of 50,331,648 samples.
This configured value for Sample Count will remain even though you have changed the channel's meas-
urement function in the [Channel] menu.
When Pretrigger Count ≠ 0, the instrument will limit the Sample Count to 1,000,000.
158
edge (Neg).
Keysight DAQ970A/DAQ973A User's Guide