ADLINK PCI-9820 - Manual (Page 34)

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• Operation Theory
stored in memory. After the initial setup, the process does not require soft-
ware intervention.
Figure 4.7 Post-trigger with re-trigger
4.4 Trigger Sources
In addition to the internal software trigger, the PCI-9820 also supports ex-
ternal analog, digital triggers and SSI triggers. Users can configure the trigger
source by software. For SSI trigger operation, please refer to section 4.7.
4.4.1 Software-Trigger
This trigger mode does not need any external trigger source. The trigger
asserts right after executing specified function calls to begin the operation.
4.4.2 External Analog Trigger
Users can choose either CH0 or CH1 as the trigger signal while using ex-
ternal analog trigger source. The trigger level can be set by software with
8-bit resolution. Please refer to table 4.1 for the ideal transfer characteristic.
Trigger Level digital setting
Trigger voltage
(
±
5V range)
Trigger voltage
(
±
1V range)
0xFF 4.96V 0.992V
0xFE 4.92V 0.984V
--- --- ---
0x81 0.04V 0.008V
0x80 0 0
0x7F -0.04V -0.008V
--- --- ---
Acquired
Data
Time
Trigger
event
Operation
start
Acquired
Data
Trigger
event