Two NI-DAQmx Read/Write attributes/properties allow you to check for disconnected sensors. The first is OpenCurrentLoopChansExist. This attribute/property returns a Boolean true if one or more channels experience an open current loop condition. The second is OpenCurrentLoopChans. This attribute/property returns an array of strings indicating which channels (if any) experienced an open current loop condition. You must query the OpenCurrentLoopChansExist attribute/property before querying the OpenCurrentLoopChans attribute/property.
OpenCurrentLoopChansExist reads the open current loop condition from the device and caches it in the driver. Subsequent reads of OpenCurrentLoopChans attribute/property will read the open current loop channel information cached in the driver from the previous OpenCurrentLoopChansExist query.