DAQmxWriteDigitalU8
int32 DAQmxWriteDigitalU8 (TaskHandle taskHandle, int32 numSampsPerChan, bool32 autoStart, float64 timeout, bool32 dataLayout, uInt8 writeArray[], int32 *sampsPerChanWritten, bool32 *reserved);
Purpose
Writes multiple 8-bit unsigned integer samples to a task that contains one or more digital output channels. Use this format for devices with up to 8 lines per port.
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Note If you configured timing for your task, your write is considered a buffered write. Buffered writes require a minimum buffer size of two samples. If you do not configure the buffer size using DAQmxCfgOutputBuffer, NI-DAQmx automatically configures the buffer when you configure sample timing. If you attempt to write one sample for a buffered write without configuring the buffer, you will receive an error. |
Parameters
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Input
|
| Name |
Type |
Description |
|
taskHandle
|
TaskHandle |
The task to write samples to. |
|
numSampsPerChan
|
int32 |
The number of samples, per channel, to write. You must pass in a value of 0 or more in order for the sample to write. If you pass a negative number, this function returns an error. |
|
autoStart
|
bool32 |
Specifies whether or not this function automatically starts the task if you do not start it. |
|
timeout
|
float64 |
The amount of time, in seconds, to wait for this function to write all the samples. The default value is 10.0 seconds. To specify an infinite wait, pass -1 (DAQmx_Val_WaitInfinitely). This function returns an error if the timeout elapses.
A value of 0 indicates to try once to write the submitted samples. If this function successfully writes all submitted samples, it does not return an error. Otherwise, the function returns a timeout error and returns the number of samples actually written. |
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dataLayout
|
bool32 |
Specifies how the samples are arranged, either interleaved or noninterleaved.
| Value |
|
Description |
|
DAQmx_Val_GroupByChannel
|
|
Group by channel (noninterleaved) |
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DAQmx_Val_GroupByScanNumber
|
|
Group by sample (interleaved) |
|
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writeArray
|
uInt8 []
|
The array of 8-bit integer samples to write to the task. |
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reserved
|
bool32 *
|
Reserved for future use. Pass NULL to this parameter. |
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Output
|
| Name |
Type |
Description |
|
sampsPerChanWritten
|
int32 *
|
The actual number of samples per channel successfully written to the buffer. |
Return Value
| Name |
Type |
Description |
|
status
|
int32 |
The error code returned by the function in the event of an error or warning. A value of 0 indicates success. A positive value indicates a warning. A negative value indicates an error. |