54
•
Operation Theory
Internal timing
signals
SSI timing
Signals
AFI timing
signals
DAQ timing
signals
SSI timing
Signals
Trigger_Out
timing signals
Figure 44: DAQ signals routing
Users can utilize the flexible timing signals through our software drivers,
and simply and correctly connect the signals with the DAQ/PXI-20XX se-
ries cards. Here is the summary of the DAQ timing signals and the corre-
sponding functionalities for DAQ/PXI-20XX series.
Timing signal category
Corresponding functi onality
SSI/PXI signals
Multiple cards synchronization
AFI signals
Control DAQ-2000 by external timing signals
AI_Trig_Out, AO_Trig_Out
Control external circuitry or boards
Table 12: Summary of user-controllable timing signals and the
corresponding functionalities
4.6.1
DAQ timing signals
The user-controllable internal timing-signals contain: (Please refer to Sec-
tion 4.1.4 for the internal timing signal definition)
1. TIMEBASE, providing TIMEBASE for all DAQ operations, which
could be from internal 40MHz oscillator, EXTTIMEBASE from I/O
connector or the SSI_TIMEBASE. Note that the frequency range of
the EXTTIMEBASE is 1MHz to 40MHz, and the EXTTIMEBASE
should be TTL -compatible.
2. AD_TRIG, the trigger signal for the A/D operation, which could come
from external digital trigger, analog trigger, internal software trigger
and SSI_AD_TRIG. Refer to Section 4.5 for detailed description.
