DAQmx Timing

DAQmx - Data Acquisition VIs and Functions

DAQmx Timing

Configures the number of samples to acquire or generate and creates a buffer when needed. The instances of this polymorphic VI correspond to the type of timing to use for the task.

The DAQmx Timing properties include all timing options included in this VI and additional timing options.

Use the pull-down menu to select an instance of this VI.

minibutton.gif  Place on the block diagram. minibutton.gif  Find on the Functions palette.

Sample Clock 

Sets the source of the Sample Clock, the rate of the Sample Clock, and the number of samples to acquire or generate.

DAQmx Timing (Sample Clock)c.gif

civrn.gif task/channels in is the name of the task or a list of virtual channels to which the operation applies. If you provide a list of virtual channels, NI-DAQmx creates a task automatically.
cdbl.gif rate specifies the sampling rate in samples per channel per second. If you use an external source for the Sample Clock, set this input to the maximum expected rate of that clock.
civrn.gif source specifies the source terminal of the Sample Clock. Leave this input unwired to use the default onboard clock of the device.
ci32.gif active edge specifies on which edges of Sample Clock pulses to acquire or generate samples.

Falling (10171) Acquire or generate samples on falling edges of the Sample Clock.
Rising (10280) Acquire or generate samples on rising edges of the Sample Clock.
cerrcodeclst.gif error in describes error conditions that occur before this VI or function runs. The default is no error. If an error occurred before this VI or function runs, the VI or function passes the error in value to error out. If an error occurs while this VI or function runs, the VI or function runs normally and sets its own error status in error out. Use the Simple Error Handler or General Error Handler VIs to display the description of the error code. Use error in and error out to check errors and to specify execution order by wiring error out from one node to error in of the next node.
cbool.gif status is TRUE (X) if an error occurred before this VI or function ran or FALSE (checkmark) to indicate a warning or that no error occurred before this VI or function ran. The default is FALSE.
ci32.gif code is the error or warning code. The default is 0. If status is TRUE, code is a negative error code. If status is FALSE, code is 0 or a warning code.
cstr.gif source identifies where an error occurred. The source string includes the name of the VI that produced the error, what inputs are in error, and how to eliminate the error.
ci32.gif sample mode specifies if the task acquires or generates samples continuously or if it acquires or generates a finite number of samples.

Continuous Samples (10123) Acquire or generate samples until the DAQmx Stop Task VI runs.
Finite Samples (10178) Acquire or generate a finite number of samples.
Hardware Timed Single Point (12522) Acquire or generate samples continuously using hardware timing without a buffer. Hardware timed single point sample mode is supported only for the sample clock and change detection timing types.
cu32.gif samples per channel specifies the number of samples to acquire or generate for each channel in the task if sample mode is Finite Samples. If sample mode is Continuous Samples, NI-DAQmx uses this value to determine the buffer size.
iivrn.gif task out is a reference to the task after this VI or function runs. If you wired a channel or list of channels to task/channels in, NI-DAQmx creates this task automatically.
ierrcodeclst.gif error out contains error information. If error in indicates that an error occurred before this VI or function ran, error out contains the same error information. Otherwise, error out describes the error status that this VI or function produces. Right-click the error out indicator on the front panel and select Explain Error from the shortcut menu for more information about the error.
ibool.gif status is TRUE (X) if an error occurred or FALSE (checkmark) to indicate a warning or that no error occurred.
ii32.gif code is the error or warning code. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code.
istr.gif source identifies where and why an error occurred. The source string includes the name of the VI that produced the error, what inputs are in error, and how to eliminate the error.

Handshaking 

Determines the number of digital samples to acquire or generate using digital handshaking between the device and a peripheral device.

DAQmx Timing (Handshaking)c.gif

civrn.gif task/channels in is the name of the task or a list of virtual channels to which the operation applies. If you provide a list of virtual channels, NI-DAQmx creates a task automatically.
cerrcodeclst.gif error in describes error conditions that occur before this VI or function runs. The default is no error. If an error occurred before this VI or function runs, the VI or function passes the error in value to error out. If an error occurs while this VI or function runs, the VI or function runs normally and sets its own error status in error out. Use the Simple Error Handler or General Error Handler VIs to display the description of the error code. Use error in and error out to check errors and to specify execution order by wiring error out from one node to error in of the next node.
cbool.gif status is TRUE (X) if an error occurred before this VI or function ran or FALSE (checkmark) to indicate a warning or that no error occurred before this VI or function ran. The default is FALSE.
ci32.gif code is the error or warning code. The default is 0. If status is TRUE, code is a negative error code. If status is FALSE, code is 0 or a warning code.
cstr.gif source identifies where an error occurred. The source string includes the name of the VI that produced the error, what inputs are in error, and how to eliminate the error.
ci32.gif sample mode specifies if the task acquires or generates samples continuously or if it acquires or generates a finite number of samples.

Continuous Samples (10123) Acquire or generate samples until the DAQmx Stop Task VI runs.
Finite Samples (10178) Acquire or generate a finite number of samples.
Hardware Timed Single Point (12522) Acquire or generate samples continuously using hardware timing without a buffer. Hardware timed single point sample mode is supported only for the sample clock and change detection timing types.
cu32.gif samples per channel specifies the number of samples to acquire or generate for each channel in the task if sample mode is Finite Samples. If sample mode is Continuous Samples, NI-DAQmx uses this value to determine the buffer size.
iivrn.gif task out is a reference to the task after this VI or function runs. If you wired a channel or list of channels to task/channels in, NI-DAQmx creates this task automatically.
ierrcodeclst.gif error out contains error information. If error in indicates that an error occurred before this VI or function ran, error out contains the same error information. Otherwise, error out describes the error status that this VI or function produces. Right-click the error out indicator on the front panel and select Explain Error from the shortcut menu for more information about the error.
ibool.gif status is TRUE (X) if an error occurred or FALSE (checkmark) to indicate a warning or that no error occurred.
ii32.gif code is the error or warning code. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code.
istr.gif source identifies where and why an error occurred. The source string includes the name of the VI that produced the error, what inputs are in error, and how to eliminate the error.

Burst (Import Clock) 

Configures when the DAQ device transfers data to a peripheral device, using an imported sample clock to control burst handshake timing.

DAQmx Timing (Burst Import Clock)c.gif

civrn.gif task/channels in is the name of the task or a list of virtual channels to which the operation applies. If you provide a list of virtual channels, NI-DAQmx creates a task automatically.
cdbl.gif sample clock rate specifies in hertz the rate of the Sample Clock.
civrn.gif sample clock source specifies the source terminal of the Sample Clock. Leave this input unwired to use the default onboard clock of the device.
ci32.gif sample clock active edge specifies on which edges of Sample Clock pulses to acquire or generate samples.

Falling (10171) Acquire or generate samples on falling edges of the Sample Clock.
Rising (10280) Acquire or generate samples on rising edges of the Sample Clock.
cerrcodeclst.gif error in describes error conditions that occur before this VI or function runs. The default is no error. If an error occurred before this VI or function runs, the VI or function passes the error in value to error out. If an error occurs while this VI or function runs, the VI or function runs normally and sets its own error status in error out. Use the Simple Error Handler or General Error Handler VIs to display the description of the error code. Use error in and error out to check errors and to specify execution order by wiring error out from one node to error in of the next node.
cbool.gif status is TRUE (X) if an error occurred before this VI or function ran or FALSE (checkmark) to indicate a warning or that no error occurred before this VI or function ran. The default is FALSE.
ci32.gif code is the error or warning code. The default is 0. If status is TRUE, code is a negative error code. If status is FALSE, code is 0 or a warning code.
cstr.gif source identifies where an error occurred. The source string includes the name of the VI that produced the error, what inputs are in error, and how to eliminate the error.
ci32.gif sample mode specifies if the task acquires or generates samples continuously or if it acquires or generates a finite number of samples.

Continuous Samples (10123) Acquire or generate samples until the DAQmx Stop Task VI runs.
Finite Samples (10178) Acquire or generate a finite number of samples.
Hardware Timed Single Point (12522) Acquire or generate samples continuously using hardware timing without a buffer. Hardware timed single point sample mode is supported only for the sample clock and change detection timing types.
cu32.gif samples per channel specifies the number of samples to acquire or generate for each channel in the task if sample mode is Finite Samples. If sample mode is Continuous Samples, NI-DAQmx uses this value to determine the buffer size.
ci32.gif pause when specifies whether the task pauses while the trigger signal is high or low.

High (10192) Pause the task while the trigger signal is high.
Low (10214) Pause the task while the trigger signal is low.
ci32.gif ready for transfer event active level specifies the polarity of the Ready for Transfer Event.

Active High (10095) Active high.
Active Low (10096) Active low.
iivrn.gif task out is a reference to the task after this VI or function runs. If you wired a channel or list of channels to task/channels in, NI-DAQmx creates this task automatically.
ierrcodeclst.gif error out contains error information. If error in indicates that an error occurred before this VI or function ran, error out contains the same error information. Otherwise, error out describes the error status that this VI or function produces. Right-click the error out indicator on the front panel and select Explain Error from the shortcut menu for more information about the error.
ibool.gif status is TRUE (X) if an error occurred or FALSE (checkmark) to indicate a warning or that no error occurred.
ii32.gif code is the error or warning code. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code.
istr.gif source identifies where and why an error occurred. The source string includes the name of the VI that produced the error, what inputs are in error, and how to eliminate the error.

Burst (Export Clock) 

Configures when the DAQ device transfers data to a peripheral device, using the onboard Sample Clock of the DAQ device to control burst handshake timing and exporting that clock for use by the peripheral device.

DAQmx Timing (Burst Export Clock)c.gif

civrn.gif task/channels in is the name of the task or a list of virtual channels to which the operation applies. If you provide a list of virtual channels, NI-DAQmx creates a task automatically.
cdbl.gif sample clock rate specifies in hertz the rate of the Sample Clock.
civrn.gif sample clock output terminal specifies the terminal to which to export the Sample Clock.
ci32.gif sample clock pulse polarity specifies the polarity of the exported Sample Clock.

Active High (10095) Active high.
Active Low (10096) Active low.
cerrcodeclst.gif error in describes error conditions that occur before this VI or function runs. The default is no error. If an error occurred before this VI or function runs, the VI or function passes the error in value to error out. If an error occurs while this VI or function runs, the VI or function runs normally and sets its own error status in error out. Use the Simple Error Handler or General Error Handler VIs to display the description of the error code. Use error in and error out to check errors and to specify execution order by wiring error out from one node to error in of the next node.
cbool.gif status is TRUE (X) if an error occurred before this VI or function ran or FALSE (checkmark) to indicate a warning or that no error occurred before this VI or function ran. The default is FALSE.
ci32.gif code is the error or warning code. The default is 0. If status is TRUE, code is a negative error code. If status is FALSE, code is 0 or a warning code.
cstr.gif source identifies where an error occurred. The source string includes the name of the VI that produced the error, what inputs are in error, and how to eliminate the error.
ci32.gif sample mode specifies if the task acquires or generates samples continuously or if it acquires or generates a finite number of samples.

Continuous Samples (10123) Acquire or generate samples until the DAQmx Stop Task VI runs.
Finite Samples (10178) Acquire or generate a finite number of samples.
Hardware Timed Single Point (12522) Acquire or generate samples continuously using hardware timing without a buffer. Hardware timed single point sample mode is supported only for the sample clock and change detection timing types.
cu32.gif samples per channel specifies the number of samples to acquire or generate for each channel in the task if sample mode is Finite Samples. If sample mode is Continuous Samples, NI-DAQmx uses this value to determine the buffer size.
ci32.gif pause when specifies whether the task pauses while the trigger signal is high or low.

High (10192) Pause the task while the trigger signal is high.
Low (10214) Pause the task while the trigger signal is low.
ci32.gif ready for transfer event active level specifies the polarity of the Ready for Transfer Event.

Active High (10095) Active high.
Active Low (10096) Active low.
iivrn.gif task out is a reference to the task after this VI or function runs. If you wired a channel or list of channels to task/channels in, NI-DAQmx creates this task automatically.
ierrcodeclst.gif error out contains error information. If error in indicates that an error occurred before this VI or function ran, error out contains the same error information. Otherwise, error out describes the error status that this VI or function produces. Right-click the error out indicator on the front panel and select Explain Error from the shortcut menu for more information about the error.
ibool.gif status is TRUE (X) if an error occurred or FALSE (checkmark) to indicate a warning or that no error occurred.
ii32.gif code is the error or warning code. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code.
istr.gif source identifies where and why an error occurred. The source string includes the name of the VI that produced the error, what inputs are in error, and how to eliminate the error.

Implicit 

Sets only the number of samples to acquire or generate without specifying timing. Typically, you should use this instance when the task does not require sample timing, such as tasks that use counters for buffered frequency measurement, buffered period measurement, or pulse train generation.

DAQmx Timing (Implicit)c.gif

civrn.gif task/channels in is the name of the task or a list of virtual channels to which the operation applies. If you provide a list of virtual channels, NI-DAQmx creates a task automatically.
cerrcodeclst.gif error in describes error conditions that occur before this VI or function runs. The default is no error. If an error occurred before this VI or function runs, the VI or function passes the error in value to error out. If an error occurs while this VI or function runs, the VI or function runs normally and sets its own error status in error out. Use the Simple Error Handler or General Error Handler VIs to display the description of the error code. Use error in and error out to check errors and to specify execution order by wiring error out from one node to error in of the next node.
cbool.gif status is TRUE (X) if an error occurred before this VI or function ran or FALSE (checkmark) to indicate a warning or that no error occurred before this VI or function ran. The default is FALSE.
ci32.gif code is the error or warning code. The default is 0. If status is TRUE, code is a negative error code. If status is FALSE, code is 0 or a warning code.
cstr.gif source identifies where an error occurred. The source string includes the name of the VI that produced the error, what inputs are in error, and how to eliminate the error.
ci32.gif sample mode specifies if the task acquires or generates samples continuously or if it acquires or generates a finite number of samples.

Continuous Samples (10123) Acquire or generate samples until the DAQmx Stop Task VI runs.
Finite Samples (10178) Acquire or generate a finite number of samples.
Hardware Timed Single Point (12522) Acquire or generate samples continuously using hardware timing without a buffer. Hardware timed single point sample mode is supported only for the sample clock and change detection timing types.
cu32.gif samples per channel specifies the number of samples to acquire or generate for each channel in the task if sample mode is Finite Samples. If sample mode is Continuous Samples, NI-DAQmx uses this value to determine the buffer size.
iivrn.gif task out is a reference to the task after this VI or function runs. If you wired a channel or list of channels to task/channels in, NI-DAQmx creates this task automatically.
ierrcodeclst.gif error out contains error information. If error in indicates that an error occurred before this VI or function ran, error out contains the same error information. Otherwise, error out describes the error status that this VI or function produces. Right-click the error out indicator on the front panel and select Explain Error from the shortcut menu for more information about the error.
ibool.gif status is TRUE (X) if an error occurred or FALSE (checkmark) to indicate a warning or that no error occurred.
ii32.gif code is the error or warning code. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code.
istr.gif source identifies where and why an error occurred. The source string includes the name of the VI that produced the error, what inputs are in error, and how to eliminate the error.

Use Waveform 

Uses the dt component of the waveform input to determine the Sample Clock rate. dt is the time in seconds between samples. If sample mode is Finite Samples, NI-DAQmx generates the number of samples in the waveform. This VI does not actually generate any samples. You must wire the same waveform to the DAQmx Write VI to generate the samples.

DAQmx Timing (Use Waveform)c.gif

civrn.gif task/channels in is the name of the task or a list of virtual channels to which the operation applies. If you provide a list of virtual channels, NI-DAQmx creates a task automatically.
cmsdt.gif waveform is the waveform to use for timing.
cerrcodeclst.gif error in describes error conditions that occur before this VI or function runs. The default is no error. If an error occurred before this VI or function runs, the VI or function passes the error in value to error out. If an error occurs while this VI or function runs, the VI or function runs normally and sets its own error status in error out. Use the Simple Error Handler or General Error Handler VIs to display the description of the error code. Use error in and error out to check errors and to specify execution order by wiring error out from one node to error in of the next node.
cbool.gif status is TRUE (X) if an error occurred before this VI or function ran or FALSE (checkmark) to indicate a warning or that no error occurred before this VI or function ran. The default is FALSE.
ci32.gif code is the error or warning code. The default is 0. If status is TRUE, code is a negative error code. If status is FALSE, code is 0 or a warning code.
cstr.gif source identifies where an error occurred. The source string includes the name of the VI that produced the error, what inputs are in error, and how to eliminate the error.
ci32.gif sample mode specifies if the task acquires or generates samples continuously or if it acquires or generates a finite number of samples.

Continuous Samples (10123) Acquire or generate samples until the DAQmx Stop Task VI runs.
Finite Samples (10178) Acquire or generate a finite number of samples.
Hardware Timed Single Point (12522) Acquire or generate samples continuously using hardware timing without a buffer. Hardware timed single point sample mode is supported only for the sample clock and change detection timing types.
iivrn.gif task out is a reference to the task after this VI or function runs. If you wired a channel or list of channels to task/channels in, NI-DAQmx creates this task automatically.
ierrcodeclst.gif error out contains error information. If error in indicates that an error occurred before this VI or function ran, error out contains the same error information. Otherwise, error out describes the error status that this VI or function produces. Right-click the error out indicator on the front panel and select Explain Error from the shortcut menu for more information about the error.
ibool.gif status is TRUE (X) if an error occurred or FALSE (checkmark) to indicate a warning or that no error occurred.
ii32.gif code is the error or warning code. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code.
istr.gif source identifies where and why an error occurred. The source string includes the name of the VI that produced the error, what inputs are in error, and how to eliminate the error.

Change Detection 

Configures the task to acquire samples on the rising and/or falling edges of the lines or ports you specify. To detect both rising and falling edges on a line or port, wire the name of that line or port to both rising edge physical channels and falling edge physical channels.

DAQmx Timing (Change Detection)c.gif

civrn.gif task/channels in is the name of the task or a list of virtual channels to which the operation applies. If you provide a list of virtual channels, NI-DAQmx creates a task automatically.
civrn.gif rising edge physical channels specifies the names of the digital lines or ports on which to detect rising edges. The DAQmx physical channel constant lists all lines and ports for devices installed in your system. You also can wire a string that contains a list or range of digital lines or ports to this input.
civrn.gif falling edge physical channels specifies the names of the digital lines or ports on which to detect falling edges. The DAQmx physical channel constant lists all lines and ports for devices installed in your system. You also can wire a string that contains a list or range of digital lines or ports to this input.
cerrcodeclst.gif error in describes error conditions that occur before this VI or function runs. The default is no error. If an error occurred before this VI or function runs, the VI or function passes the error in value to error out. If an error occurs while this VI or function runs, the VI or function runs normally and sets its own error status in error out. Use the Simple Error Handler or General Error Handler VIs to display the description of the error code. Use error in and error out to check errors and to specify execution order by wiring error out from one node to error in of the next node.
cbool.gif status is TRUE (X) if an error occurred before this VI or function ran or FALSE (checkmark) to indicate a warning or that no error occurred before this VI or function ran. The default is FALSE.
ci32.gif code is the error or warning code. The default is 0. If status is TRUE, code is a negative error code. If status is FALSE, code is 0 or a warning code.
cstr.gif source identifies where an error occurred. The source string includes the name of the VI that produced the error, what inputs are in error, and how to eliminate the error.
ci32.gif sample mode specifies if the task acquires samples continuously or if it acquires a finite number of samples.

Continuous Samples (10123) Acquire samples until the DAQmx Stop Task VI runs.
Finite Samples (10178) Acquire a finite number of samples.
Hardware Timed Single Point (12522) Acquire samples continuously using hardware timing without a buffer. Hardware timed single point sample mode is supported only for the sample clock and change detection timing types.
ci32.gif samples per channel specifies the number of samples to acquire from each channel in the task if sample mode is Finite Samples.
iivrn.gif task out is a reference to the task after this VI or function runs. If you wired a channel or list of channels to task/channels in, NI-DAQmx creates this task automatically.
ierrcodeclst.gif error out contains error information. If error in indicates that an error occurred before this VI or function ran, error out contains the same error information. Otherwise, error out describes the error status that this VI or function produces. Right-click the error out indicator on the front panel and select Explain Error from the shortcut menu for more information about the error.
ibool.gif status is TRUE (X) if an error occurred or FALSE (checkmark) to indicate a warning or that no error occurred.
ii32.gif code is the error or warning code. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code.
istr.gif source identifies where and why an error occurred. The source string includes the name of the VI that produced the error, what inputs are in error, and how to eliminate the error.

Pipelined Sample Clock 

Sets the source of the Sample Clock, the rate of the Sample Clock, and the number of samples to acquire or generate. The device acquires or generates samples on each Sample Clock edge, but it does not respond to certain triggers until a few Sample Clock edges later. Pipelining allows higher data transfer rates at the cost of increased trigger response latency. Refer to the device documentation for information about which triggers pipelining affects.

This timing type allows handshaking using the Pause trigger and either the Ready for Transfer event or the Data Active event. Refer to the device documentation for more information.

This timing type is supported only by the NI 6536 and NI 6537.

DAQmx Timing (Pipelined Sample Clock)c.gif

civrn.gif task/channels in is the name of the task or a list of virtual channels to which the operation applies. If you provide a list of virtual channels, NI-DAQmx creates a task automatically.
cdbl.gif rate specifies the sampling rate in samples per channel per second. If you use an external source for the Sample Clock, set this input to the maximum expected rate of that clock.
civrn.gif source specifies the source terminal of the Sample Clock. Leave this input unwired to use the default onboard clock of the device.
ci32.gif active edge specifies on which edges of Sample Clock pulses to acquire or generate samples.

Falling (10171) Acquire or generate samples on falling edges of the Sample Clock.
Rising (10280) Acquire or generate samples on rising edges of the Sample Clock.
cerrcodeclst.gif error in describes error conditions that occur before this VI or function runs. The default is no error. If an error occurred before this VI or function runs, the VI or function passes the error in value to error out. If an error occurs while this VI or function runs, the VI or function runs normally and sets its own error status in error out. Use the Simple Error Handler or General Error Handler VIs to display the description of the error code. Use error in and error out to check errors and to specify execution order by wiring error out from one node to error in of the next node.
cbool.gif status is TRUE (X) if an error occurred before this VI or function ran or FALSE (checkmark) to indicate a warning or that no error occurred before this VI or function ran. The default is FALSE.
ci32.gif code is the error or warning code. The default is 0. If status is TRUE, code is a negative error code. If status is FALSE, code is 0 or a warning code.
cstr.gif source identifies where an error occurred. The source string includes the name of the VI that produced the error, what inputs are in error, and how to eliminate the error.
ci32.gif sample mode specifies if the task acquires or generates samples continuously or if it acquires or generates a finite number of samples.

Continuous Samples (10123) Acquire or generate samples until the DAQmx Stop Task VI runs.
Finite Samples (10178) Acquire or generate a finite number of samples.
Hardware Timed Single Point (12522) Acquire or generate samples continuously using hardware timing without a buffer. Hardware timed single point sample mode is supported only for the sample clock and change detection timing types.
cu32.gif samples per channel specifies the number of samples to acquire or generate for each channel in the task if sample mode is Finite Samples. If sample mode is Continuous Samples, NI-DAQmx uses this value to determine the buffer size.
iivrn.gif task out is a reference to the task after this VI or function runs. If you wired a channel or list of channels to task/channels in, NI-DAQmx creates this task automatically.
ierrcodeclst.gif error out contains error information. If error in indicates that an error occurred before this VI or function ran, error out contains the same error information. Otherwise, error out describes the error status that this VI or function produces. Right-click the error out indicator on the front panel and select Explain Error from the shortcut menu for more information about the error.
ibool.gif status is TRUE (X) if an error occurred or FALSE (checkmark) to indicate a warning or that no error occurred.
ii32.gif code is the error or warning code. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code.
istr.gif source identifies where and why an error occurred. The source string includes the name of the VI that produced the error, what inputs are in error, and how to eliminate the error.