Solution
We need to take into account electromagnetic compatibility (EMC) guidelines for NI PXIe-4138/4139.
This products were tested and complies with the regulatory requirements and limits for EMC stated in the
product specifications. These requirements and limits provide reasonable protection against harmful interference when the product is operated in the intended operational electromagnetic environment.
As indicated in the getting started guide for the
PXIe-4138 or
PXIe-4139, the maximum allowable cable length is 3 m (10 ft).