Why Is My DAQ Gain Affected When I Remove "ob0" from My SCXI Channel String? Primary Software: LabVIEW Development Systems>>Full Development SystemPrimary Software Version: 7.1 Primary Software Fixed Version: N/A Secondary Software: LabVIEW Development Systems, Driver Software>>NI-DAQmx, Driver Software>>NI-DAQ Hardware: Multifunction DAQ (MIO), SCXI
Problem: I use the syntax "obz!scx!mdy!a" in my program when acquiring signals from my SCXI module. With input limits set to -0.001 V to + 0.001 V on my SCXI module, specifying the channel string "ob0!sc1!md1!0:7" causes the gain on the DAQ board to be set to 5. Specifying the channel string "sc1!md1!0:7" causes the gain to be set to 1. In other words, leaving off the on-board channel number prevents the on-board channel's gain from being set. Why is this? Solution: If you leave "ob0" out of the channel string, LabVIEW will choose the default gain of your Data Acquisition board (which is usually the lowest setting). However, If you leave "ob0" in the channel string, then LabVIEW will calculate the best gain ratio available between SCXI and your DAQ board. Related Links: KnowledgeBase 065GM6NI: Valid SCXI Channel String Arrays under LabVIEW Attachments:
Report Date: 01/12/2001 Last Updated: 12/07/2004 Document ID: 25BE4GHE |
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