52
•
Using the DAS-1700 Series with DriverLINX
Keithley DAS-1700 Series
Digital Stop Event (Pre- and About-Triggering)
The DAS-1700 can acquire analog input samples until the hardware detects a digital
trigger condition. Use pre-triggering when you want to synchronize the end of data
acquisition with an external signal.
How to set up the DAS-1700 Series for pre-triggered analog input.
Digital Stop Events contain mask, pattern, and match fields. The mask is logically
ANDed with the digital input data on the Logical Channel and then compared with
the pattern for a match/mismatch.
•
Specify the Channel as
2
. For hardware-independence, you can specify
the hardware external trigger channel by the symbolic constant,
DI_EXTTRG.
•
Users should connect the external trigger signal to the TGIN line.
•
Specify the Mask property as
1
, or
Bit 0
, to indicate that DriverLINX
should only compare a 1-bit digital input value against the Pattern
property.
•
Specify the Match property as
Not equals
.
•
Specify the Pattern property as
0
for a rising, or positive, edge trigger
(
≠
0) or
1
for a falling, or negative, edge trigger (
≠
1).
•
Specify the Delay property as an integer from 0 to
2
2
16
−
. The DAS-
1700 continues sampling until it obtains this number of samples after
the trigger. The number must be a multiple of the number of channels in
the channel list.
•
You cannot use a digital stop trigger with a gated clock.
•
If both the start trigger and stop trigger are digital events, they must
have identical Pattern settings.
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