Overcurrent Detection

Two NI-DAQmx Read attributes/properties allow you to check for shorted channels. The first is Overcurrent Chans Exist. This attribute/property returns a Boolean true if one or more channels experience an overcurrent condition. The second is Overcurrent Chans. This attribute/property returns an array of strings indicating which channels (if any) experienced an overcurrent condition. You must query the Overcurrent Chans Exist attribute/property before querying the Overcurrent Chans attribute/property.

Overcurrent Chans Exist reads the overcurrent condition from the device and caches it in the driver. Subsequent reads of Overcurrent Chans attribute/property will read the overcurrent channel information cached in the driver from the previous Overcurrent Chans Exist query.

Note  NI-DAQmx returns all data whether or not a short occurs. If your application requires overcurrent checking, it is recommended that you read the overcurrent attributes/properties after each call to Read. Your program should discard questionable data or return a flag when the driver reports a short.

Note  IEPE must be turned on for overcurrent detection to work. If IEPE is not turned on, an error is returned when Overcurrent Chans Exist is read.