How to Migrate Counter Period Tasks from M Series to mioDAQ Devices

This document guides you through migrating a counter period measurement task from an older M Series data acquisition device, such as the USB-6210, to a newer mioDAQ device, such as the USB-6421. 

When migrating these tasks to newer architectures, your LabVIEW application may return no data on your measurement indicators. This occurs because older M Series devices allow default routing of counter terminals, such as using PFI0 by default. Whereas newer architectures like mioDAQ do not assume these default routings and require you to explicitly assign the input terminal.

To complete this procedure, you will need

• LabVIEW development environment version 2024 or later,
• NI-DAQmx driver,
• A mioDAQ device, such as the USB-6421,

• Locate the DAQmx Create Virtual Channel VI configured for a Counter Input measurement.
• Place a DAQmx Channel Property Node on the block diagram immediately after the DAQmx Create Virtual Channel VI.
• Wire the task out and error out terminals of the DAQmx Create Virtual Channel VI to the corresponding input terminals of the DAQmx Channel Property Node.
• Configure the property node by selecting Counter Input >> General Properties >> Input Terminals >> Period >> Terminal. Verify that the selected property is CI.Period.Term.
• Right-click the CI.Period.Term input terminal and select Create >> Constant or Create >> Control.
• Specify the input terminal using the device terminal path. For example, enter /Dev1/PFI0.
• Wire the output of the DAQmx Channel Property Node to the DAQmx Timing VI.

After adding the explicit terminal routing, your application will successfully initialize the counter task, route the physical signal from the designated PFI pin to the counter, and start returning accurate period measurement values on your indicators.

Before

After