Download PCI/PXI-7030 and LabVIEW RT User Manual

Appendix A
LabVIEW RT Function Reference — RT Incremental Single Write
RT Incremental Single Write
Use the RT Incremental Single Write VI to share several data values between VIs running in
the RT Engine and VIs running on the Host PC when your VIs are running in continuous loops
and your loop speed needs to be as fast as possible.The RT Incremental Single Write VI writes
an array of singles data to shared memory, but only writes 16 bits of data each time it is called.
Because it only writes 16 bits of data each time it is called, this VI takes little time to execute,
but may require several loop iterations to write each single data value to memory.
Note The RT Incremental Single Write VI only writes new data to shared memory after
the previously written value has been read by RT incremental Single Read VI. The design
of this subVI is not to write every value to memory, but rather to write the latest values to
shared memory, which can result in lost data points.
device is the device number you assigned to the RT Series processor board
during configuration. This parameter defaults to 1.
byte offset is the location in memory to start reading data.
data is the array of data read from shared memory.
iteration is the current iteration of the loop. This parameter should be
wired to the iteration terminal of the while loop in which this VI is used.
error in describes error conditions that exist before this VI executes. If an
error already occurred, the VI does not execute.
device out is the device number you assigned to the RT Series processor
board during configuration. This parameter defaults to 1.
next byte offset is the next available location in shared memory after this
VI runs.
error out contains error information. If the error in cluster indicated an
error, the error out cluster contains the same information. Otherwise,
error out describes the error status of this VI.
For examples using this VI, refer to the One Channel PID - RT Engine.vi and One
Channel PID - Host PC.vi, located in the LabVIEW\Examples\RT directory.
© National Instruments Corporation
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PCI/PXI-7030 and LabVIEW RT User Manual