National Instruments BridgeVIEW Manuel D’Utilisation

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Appendix A
HMI Function Reference
© National Instruments Corporation
A-61
value timestamp returns the timestamp for when the tag value was last 
updated.
error indicates that an error occurred when executing the Read Tag (string) 
VI, or that the value output returned by Read Tag(string) is not valid. 
See value status for the specific error condition.
shutdown indicates that the BridgeVIEW Engine is shutting down. In this 
case, Read Tag (string) no longer waits for Tags to be updated and returns 
immediately with both timeout and shutdown TRUE. You can use 
shutdown to exit any loop that uses the Read Tag (string) VI.
changed? is TRUE when the Read Tag (string) VI returns a new value 
from the Real-Time Database. If changed? is FALSE, Read Tag (string) 
probably timed out before the tag value was updated.