ADLINK DAQe-2214 - Manual (Page 76)

64 Operation Theory
4.5 Trigger Sources
ADLINK provides flexible trigger selections in the DAQ-/DAQe-
2213/2214 card. In addition to the internal software trigger, the
DAQ-/DAQe-2213/2214 card also supports external analog, digital
triggers, and SSI triggers. You can configure the trigger source by
software for A/D and D/A processes individually.
Software-Trigger
This trigger mode does not need any external trigger source. The
trigger asserts right after you execute the specified function calls
to begin the operation.
External Analog Trigger
The analog trigger circuitry routing is shown in Figure 4-29. The
analog multiplexer can select either a direct analog input from the
EXTATRIG pin (SRC1) in the 68-pin connector or the input signal
of ADC (SRC2). That is, one of the four channel inputs you can
select as a trigger source. Both trigger sources can be used for all
trigger modes. The range of trigger level for SRC1 is ±10V and the
resolution is 78 mV (refer to Table 4-4), while the trigger range of
SRC2 is the full-scale range of the selected channel input and the
resolution is the desired range divided by 256. For example, if the
channel input selected to be the trigger source is set bipolar and
±5 V range, the trigger voltage would be 4.96V when the trigger
level code is set to 0xFF while -4.96V when the code is set to
0x01.
Figure 4-29: Analog Trigger Block Diagram