National Instruments BridgeVIEW ユーザーズマニュアル

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Appendix A
HMI Function Reference
© National Instruments Corporation
A-57
value is the latest bit array value of the bit array tag read from the 
Real-Time Database.
value timestamp returns the timestamp for when the tag value was last 
updated. 
error indicates that an error occurred when executing the Read Tag (bit 
array) VI, or that the value output returned by Read Tag (bit array) 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 (bit array) 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 Read Tag (bit array). 
changed? is TRUE when Read Tag (bit array) returns a new value from the 
Real-Time Database. If changed? is FALSE, Read Tag (bit array) probably 
timed out before the tag value was updated.