Hello,
FieldPoint Dual Channel modules are isolated from each other. For analog modules, such as the FP-AI-V5, the two channels on the module share the same common, so they are considered single-ended. However, if you only use one channel, you are not sharing the common with other channels and are therefore making a differential measurement.
To use the FP-AI-V5 as a differential module, just use only one channel.
Regards,
Green Rives
FieldPoint Product Support Engineer
National Instruments