ADLINK PCI-9524 - Manual (Page 86)

70 Operation Theory
PCI-9524 ADLINK Technology Inc.
User’s Manual Copyright 2008
4.6.1 Isolated Digital Inputs
PCI-9524 has isolated digital inputs based on non-polarity opto-
coupler devices, and accepts input signals in either direction. Each
isolated digital input can be connected to external devices with dif-
ferent common-mode voltages, without interfering with each other.
4.6.2 Isolated Digital Outputs
PCI-9524 offers isolated digital outputs based on N-MOS sink driv-
ers; they handle larger power and are sturdier than conventional
Darlington output stages. However, when connecting to inductive
loads, be sure to utilize the built-in fly-wheel diodes to prevent sink
drivers from being destroyed by kick-back voltage. Follow the sig-
nal connection illustrated in Figure 3-15 when connecting to induc-
tive loads.
4.7 Trigger Sources
PCI-9524 supports four trigger sources, including software trigger,
external digital trigger, pulse comparator trigger, and position com-
parator trigger.
4.7.1 Software-Trigger
The trigger asserts immediately after users execute the specified
API function calls to begin data acquisition.
4.7.2 External Digital Trigger
An external digital trigger occurs when a rising edge or a falling
edge is detected on the digital signal connected to PCI-9524's iso-
lated digital input channel #0.