User`s guide

PCI-2513 User's Guide Functional Details
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When setting a detection window, keep a scan period in mind. This applies to analog inputs and counter inputs.
Quickly changing analog input voltages can step over a setpoint window if not sampled often enough.
There are three possible solutions for overcoming this problem:
 Shorten the scan period to give more timing resolution on the counter values or analog values.
 Widen the setpoint window by increasing limit A, and/or lowering limit B.
 A combination of both solutions (1 and 2) could be made.