ADLINK PCI-9524 - Manual (Page 87)

Operation Theory 71
ADLINK Technology Inc. PCI-9524
Copyright 2008 User’s Manual
This trigger source can work together with an external optical-
approximation-sensor and starts AI acquisition when the target
test device is placed in an appropriate position.
Users can program the trigger polarity through ADLINK's software
drivers easily. Note that the level of the external digital trigger sig-
nal shall be compliant with the transition thresholds of the isolated
digital input, with a minimum pulse width of 1ms.
If re-trigger is enabled, the AI acquisition accepts a new trigger
after the specified number of samples has been readily acquired;
else the trigger signal is ignored.
Figure 4-9: External digital trigger
4.7.3 Pulse Comparator Trigger
The pulse-command generator has a built-in pulse comparator
that generates an AD trigger signal when the number of pulses
generated has reached a user specified threshold.
This trigger can be used whenever user applications require that
AI acquisition begins after the external servo motor/stepper is
actuated and positioned accordingly. For example, a destructive
material-testing-system, that finding the maximum tension/stress a
specimen-under-test can tolerate, will shut down before the speci-
men is broken down. It is common for such a system to pre-press