Open Current Loop Detection

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

Open Current Loop Chans Exist reads the open current loop condition from the device and caches it in the driver. Subsequent reads of Open Current Loop Chans attribute/property will read the open current loop channel information cached in the driver from the previous Open Current Loop Chans Exist query.

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

Note  IEPE must be turned on for open current loop detection to work. If IEPE is not turned on, an error is returned when Open Current Loop Chans is read.