Memwrite.vi – Measurement Computing UL for NI LabVIEW User Manual

Page 93

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Universal Library Virtual Instruments (VIs)

Memory board VIs

MemWrite.VI

Writes data from an array to the memory card.

Summary:

Inputs:

BoardNum

[U32] - The board number assigned when installed with InstaCal. Can

be 0 to 100.

DataBuffer

[U16] - Pointer to the data array.

FirstPoint

[I32] - Index of first point to write or

FROMHERE

.

Count

[I32] - Number of samples (words) to write.

Output:

ErrCode

[I32] - Error code. See ErrMsg.VI

Arguments:

BoardNum

The board number associated with a board when it was installed with InstaCal.

DataBuffer

Buffer containing data to be written to the external memory board.

FirstPoint

Use

the

FirstPoint

argument to specify where in the board's memory to write the

first point. For example, to write to locations #200 - #250, set

FirstPoint

=200 and

Count

=50.

To write a large amount of data to the board in small portions, set

FirstPoint

to

FROMHERE

(-1) to write each successive portion. Using

FROMHERE

(-1) speeds up the

operation of MemWrite when working with large amounts of data.

Count

Specifies the number of words to be written to the external memory card.

Count

must be equal to or less than the size of

DataBuffer

.

ErrCode

Error code from the Universal Library. Zero if no error occurred. Use the ErrMsg

VI to convert

ErrCode

into a readable string.

Notes:

DT Connect conflicts - The MemWrite VI can not be called while a DT Connect transfer is in progress. For
example, if you start collecting A/D data to the memory board in the background (by calling AInScBg.VI or
AInScFg.VI with the

DTCONNECT

+

BACKGROUND

options). You can not call MemWrite until the AInScBg.VI or

AInScFg.VI has completed. If you do you will get a

DTACTIVE

error.

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