Sequencing Steps to Reuse Hardware

When you configure a step to use a hardware device, the step reserves the device so that no other step or other application can use the device. However, you might want to reuse the same device in one project. You can use a Sequence step to pause the execution of other steps in the project while one step uses the device, thereby allowing multiple steps in the same project to use the same hardware.

For example, if you are using a data acquisition device and you want to acquire signals from different channels at different rates, you can use the Sequence step to acquire a signal from one channel at one rate and then pause that acquisition while you acquire a signal from another channel at another rate. If you try to set up the same project without a Sequence step, LabVIEW SignalExpress returns an error because only one executing step can use a single hardware device at a time.

Note  When you use the Sequence step to reuse hardware, you cannot perform a continuous signal acquisition because LabVIEW SignalExpress stops and starts the hardware device.

Complete the following steps to allow multiple steps to use the same hardware.

1. Install the hardware device, connect it to the PC, and configure LabVIEW SignalExpress to begin acquiring signals from the hardware device.
2. Add a Sequence step to the Project View after the Acquire Signals step.
3. On the Step Setup tab for the Sequence step, select Run preceding steps before following steps and place a checkmark in the Allow hardware reuse checkbox.
4. Add another Acquire Signals step to the Project View.
5. Configure the second Acquire Signals step to acquire a signal from the same hardware device as the first Acquire Signals step.
6. Click the Run button to run the project. For each iteration of the project, LabVIEW SignalExpress runs the first Acquire Signals step once, pauses the execution of that step and reconfigures the hardware device for the second acquisition, runs the second Acquire Signals step once, then pauses the execution of that step and reconfigures the hardware device for the first step.