NI DAQMX Write Attributes

Write Attributes

See how to get and set attributes.

• DAQmx_Write_RelativeTo
• DAQmx_Write_Offset
• DAQmx_Write_RegenMode
• Status
  • DAQmx_Write_CurrWritePos
  • Overcurrent
    • DAQmx_Write_OvercurrentChansExist
    • DAQmx_Write_OvercurrentChans
  • Overtemperature
    • DAQmx_Write_OvertemperatureChansExist
    • DAQmx_Write_OvertemperatureChans
  • External Overvoltage
    • DAQmx_Write_ExternalOvervoltageChansExist
    • DAQmx_Write_ExternalOvervoltageChans
  • Overload
    • DAQmx_Write_OverloadedChansExist
    • DAQmx_Write_OverloadedChans
  • Open Current Loop
    • DAQmx_Write_OpenCurrentLoopChansExist
    • DAQmx_Write_OpenCurrentLoopChans
  • Power Supply Fault
    • DAQmx_Write_PowerSupplyFaultChansExist
    • DAQmx_Write_PowerSupplyFaultChans
  • Synchronization
    • DAQmx_Write_Sync_UnlockedChansExist
    • DAQmx_Write_Sync_UnlockedChans
  • DAQmx_Write_SpaceAvail
  • DAQmx_Write_TotalSampPerChanGenerated
  • Accessory
    • DAQmx_Write_AccessoryInsertionOrRemovalDetected
    • DAQmx_Write_DevsWithInsertedOrRemovedAccessories
• Advanced
  • DAQmx_Write_RawDataWidth
  • DAQmx_Write_NumChans
  • DAQmx_Write_WaitMode
  • DAQmx_Write_SleepTime
  • Digital Output
    • DAQmx_Write_DigitalLines_BytesPerChan

DAQmx_Write_RelativeTo

Data Type:	int32
Description:	Specifies the point in the buffer at which to write data. If you also specify an offset with DAQmx_Write_Offset, the write operation begins at that offset relative to this point you select with this property.

Valid values

DAQmx_Val_FirstSample	10424	Write samples relative to the first sample.
DAQmx_Val_CurrWritePos	10430	Write samples relative to the current position in the buffer.

You can get/set/reset this attribute using:   DAQmxGetWriteAttribute   DAQmxSetWriteAttribute   DAQmxResetWriteAttribute

DAQmx_Write_Offset

Data Type:	int32
Description:	Specifies in samples per channel an offset at which a write operation begins. This offset is relative to the location you specify with DAQmx_Write_RelativeTo.

You can get/set/reset this attribute using:   DAQmxGetWriteAttribute   DAQmxSetWriteAttribute   DAQmxResetWriteAttribute

DAQmx_Write_RegenMode

Data Type:	int32
Description:	Specifies whether to allow NI-DAQmx to generate the same data multiple times.

Valid values

DAQmx_Val_AllowRegen	10097	Allow NI-DAQmx to regenerate samples that the device previously generated. When you choose this value, the write marker returns to the beginning of the buffer after the device generates all samples currently in the buffer.
DAQmx_Val_DoNotAllowRegen	10158	Do not allow NI-DAQmx to regenerate samples the device previously generated. When you choose this value, NI-DAQmx waits for you to write more samples to the buffer or until the timeout expires.

You can get/set/reset this attribute using:   DAQmxGetWriteAttribute   DAQmxSetWriteAttribute   DAQmxResetWriteAttribute

Status

DAQmx_Write_CurrWritePos

Data Type:	uInt64
Description:	Indicates the position in the buffer of the next sample to generate. This value is identical for all channels in the task.
Restrictions:	Not Settable

You can get this attribute using:   DAQmxGetWriteAttribute

Overcurrent

DAQmx_Write_OvercurrentChansExist

Data Type:	bool32
Description:	Indicates if the device(s) detected an overcurrent condition for any channel in the task. Reading this property clears the overcurrent status for all channels in the task. You must read this property before you read DAQmx_Write_OvercurrentChans. Otherwise, you will receive an error.
Restrictions:	Not Settable

You can get this attribute using:   DAQmxGetWriteAttribute

DAQmx_Write_OvercurrentChans

Data Type:	char*
Description:	Indicates a list of names of any virtual channels in the task for which an overcurrent condition has been detected. You must read DAQmx_Write_OvercurrentChansExist before you read this property. Otherwise, you will receive an error.
Restrictions:	Not Settable

You can get this attribute using:   DAQmxGetWriteAttribute

Overtemperature

DAQmx_Write_OvertemperatureChansExist

Data Type:	bool32
Description:	Indicates if the device(s) detected an overtemperature condition in any virtual channel in the task. Reading this property clears the overtemperature status for all channels in the task. You must read this property before you read DAQmx_Write_OvertemperatureChans. Otherwise, you will receive an error.
Restrictions:	Not Settable

You can get this attribute using:   DAQmxGetWriteAttribute

DAQmx_Write_OvertemperatureChans

Data Type:	char*
Description:	Indicates a list of names of any overtemperature virtual channels. You must read DAQmx_Write_OvertemperatureChansExist before you read this property. Otherwise, you will receive an error. The list of names may be empty if the device cannot determine the source of the overtemperature.
Restrictions:	Not Settable

You can get this attribute using:   DAQmxGetWriteAttribute

External Overvoltage

DAQmx_Write_ExternalOvervoltageChansExist

Data Type:	bool32
Description:	Indicates if the device(s) detected an External Overvoltage condition for any channel in the task. Reading this property clears the External Overvoltage status for all channels in the task. You must read this property before you read External OvervoltageChans. Otherwise, you will receive an error.
Restrictions:	Not Settable

You can get this attribute using:   DAQmxGetWriteAttribute

DAQmx_Write_ExternalOvervoltageChans

Data Type:	char*
Description:	Indicates a list of names of any virtual channels in the task for which an External Overvoltage condition has been detected. You must read External OvervoltageChansExist before you read this property. Otherwise, you will receive an error.
Restrictions:	Not Settable

You can get this attribute using:   DAQmxGetWriteAttribute

Overload

DAQmx_Write_OverloadedChansExist

Data Type:	bool32
Description:	Indicates if the device(s) detected an overload in any virtual channel in the task. Reading this property clears the overload status for all channels in the task. You must read this property before you read DAQmx_Write_OverloadedChans. Otherwise, you will receive an error.
Restrictions:	Not Settable

You can get this attribute using:   DAQmxGetWriteAttribute

DAQmx_Write_OverloadedChans

Data Type:	char*
Description:	Indicates a list of names of any overloaded virtual channels in the task. You must read DAQmx_Write_OverloadedChansExist before you read this property. Otherwise, you will receive an error.
Restrictions:	Not Settable

You can get this attribute using:   DAQmxGetWriteAttribute

Open Current Loop

DAQmx_Write_OpenCurrentLoopChansExist

Data Type:	bool32
Description:	Indicates if the device(s) detected an open current loop for any channel in the task. Reading this property clears the open current loop status for all channels in the task. You must read this property before you read DAQmx_Write_OpenCurrentLoopChans. Otherwise, you will receive an error.
Restrictions:	Not Settable

You can get this attribute using:   DAQmxGetWriteAttribute

DAQmx_Write_OpenCurrentLoopChans

Data Type:	char*
Description:	Indicates a list of names of any virtual channels in the task for which the device(s) detected an open current loop. You must read DAQmx_Write_OpenCurrentLoopChansExist before you read this property. Otherwise, you will receive an error.
Restrictions:	Not Settable

You can get this attribute using:   DAQmxGetWriteAttribute

Power Supply Fault

DAQmx_Write_PowerSupplyFaultChansExist

Data Type:	bool32
Description:	Indicates if the device(s) detected a power supply fault for any channel in the task. Reading this property clears the power supply fault status for all channels in the task. You must read this property before you read DAQmx_Write_PowerSupplyFaultChans. Otherwise, you will receive an error.
Restrictions:	Not Settable

You can get this attribute using:   DAQmxGetWriteAttribute

DAQmx_Write_PowerSupplyFaultChans

Data Type:	char*
Description:	Indicates a list of names of any virtual channels in the task that have a power supply fault. You must read DAQmx_Write_PowerSupplyFaultChansExist before you read this property. Otherwise, you will receive an error.
Restrictions:	Not Settable

You can get this attribute using:   DAQmxGetWriteAttribute

Synchronization

DAQmx_Write_Sync_UnlockedChansExist

Data Type:	bool32
Description:	Indicates whether the target is currently locked to the grand master. Devices may report PLL Unlock either during acquisition or after acquisition.
Restrictions:	Not Settable

You can get this attribute using:   DAQmxGetWriteAttribute

DAQmx_Write_Sync_UnlockedChans

Data Type:	char*
Description:	Indicates the channels from devices in an unlocked target.
Restrictions:	Not Settable

You can get this attribute using:   DAQmxGetWriteAttribute

DAQmx_Write_SpaceAvail

Data Type:	uInt32
Description:	Indicates in samples per channel the amount of available space in the buffer.
Restrictions:	Not Settable

You can get this attribute using:   DAQmxGetWriteAttribute

DAQmx_Write_TotalSampPerChanGenerated

Data Type:	uInt64
Description:	Indicates the total number of samples generated by each channel in the task. This value is identical for all channels in the task.
Restrictions:	Not Settable

You can get this attribute using:   DAQmxGetWriteAttribute

Accessory

DAQmx_Write_AccessoryInsertionOrRemovalDetected

Data Type:	bool32
Description:	Indicates if any devices in the task detected the insertion or removal of an accessory since the task started. Reading this property clears the accessory change status for all channels in the task. You must read this property before you read DAQmx_Write_DevsWithInsertedOrRemovedAccessories. Otherwise, you will receive an error.
Restrictions:	Not Settable

You can get this attribute using:   DAQmxGetWriteAttribute

DAQmx_Write_DevsWithInsertedOrRemovedAccessories

Data Type:	char*
Description:	Indicates the names of any devices that detected the insertion or removal of an accessory since the task started. You must read DAQmx_Write_AccessoryInsertionOrRemovalDetected before you read this property. Otherwise, you will receive an error.
Restrictions:	Not Settable

You can get this attribute using:   DAQmxGetWriteAttribute

Advanced

DAQmx_Write_RawDataWidth

Data Type:	uInt32
Description:	Indicates in bytes the required size of a raw sample to write to the task.
Restrictions:	Not Settable

You can get this attribute using:   DAQmxGetWriteAttribute

DAQmx_Write_NumChans

Data Type:	uInt32
Description:	Indicates the number of channels that an NI-DAQmx Write function writes to the task. This value is the number of channels in the task.
Restrictions:	Not Settable

You can get this attribute using:   DAQmxGetWriteAttribute

DAQmx_Write_WaitMode

Data Type:	int32
Description:	Specifies how an NI-DAQmx Write function waits for space to become available in the buffer.

Valid values

DAQmx_Val_Poll	12524	Repeatedly check for available buffer space as fast as possible. This mode allows for the highest sampling rates at the expense of CPU efficiency.
DAQmx_Val_Yield	12525	Repeatedly check for available buffer space, but yield control to other threads after each check. This mode offers a balance between sampling rate and CPU efficiency.
DAQmx_Val_Sleep	12547	Check for available buffer space once per the amount of time specified in DAQmx_Write_SleepTime.

You can get/set/reset this attribute using:   DAQmxGetWriteAttribute   DAQmxSetWriteAttribute   DAQmxResetWriteAttribute

DAQmx_Write_SleepTime

Data Type:	float64
Description:	Specifies in seconds the amount of time to sleep after checking for available buffer space if DAQmx_Write_WaitMode is DAQmx_Val_Sleep.

You can get/set/reset this attribute using:   DAQmxGetWriteAttribute   DAQmxSetWriteAttribute   DAQmxResetWriteAttribute

Digital Output

DAQmx_Write_DigitalLines_BytesPerChan

Data Type:	uInt32
Description:	Indicates the number of Boolean values expected per channel in a sample for line-based writes. This property is determined by the channel in the task with the most digital lines. If a channel has fewer lines than this number, NI-DAQmx ignores the extra Boolean values.
Restrictions:	Not Settable

You can get this attribute using:   DAQmxGetWriteAttribute