Solution
In a multifunction DAQ device, the total number of possible concurrent tasks depends on whether you are running tasks that use
hardware timing or software (on demand) timing †.
Hardware-Timed Tasks
Hardware-timed tasks require timing information from the System Timing Controller to use for sample clocks, reference clocks, triggers, etc. The following table illustrates the number of hardware-timed tasks available to the user.
Hardware-Timed Tasks | # of Tasks per Device |
| Analog Input | 1 |
| Analog Output | 1 |
| Counter Input | N†† |
| Counter Output | N†† |
| Digital Input | 1 |
| Digital Output | 1 |
Software-Timed Tasks
Most software-timed tasks do not require a signal from a System Timing Controller in order to run. Software-timed means the host computer is controlling how often a sample is read from or written to the module.
| Software-Timed (On Demand) Tasks | # of Tasks per Device |
| Analog Input | 1 |
| Analog Output | 1 Task for each AO channel††† |
| Counter Input | N†† |
| Counter Output | N†† |
| Digital Input | 1 Task for each digital line capable of Digital Input |
| Digital Output | 1 Task for each digital line capable of Digital Output |
Note: Some digital output devices require reserving and starting each DAQmx task in a specific order. If
DAQmx Start Task is producing error
-201133, see
Error -201133 in LabVIEW™ When Running Multiple Digital Output DAQmx Task .
† It is possible to have Hardware and Software tasks running simultaneously, considering the maximum number of tasks for each timing mode.
††The number of counter tasks is always limited by the number of counters you have. Depending on whether you are using a
counter task that uses multiple counters (like measuring frequency using the two counter method), you may be restricted to fewer counter tasks.
†††67xx cards have one DAC for every four channels, so for these cards you only use one task for every 4 AO channels. In LabVIEW, you will sum them up in a style like Dev1/ao0:3, Dev1/ao4:7, ... etc.