Dear db0070,
Thank you for your question. Unfortunately, the use of expansion systems and raisers is not supported by National Instruments.
In terms of upgrading your test system, PCI does not offer a scalable solution. I am wondering whether you have considered one of our other platforms, for example cDAQ, cRIO or PXI. All of which have expansion chassis available.
I would recommend contacting your local National Instruments office to discuss your application, this will allow us to give you the best support we can.
To find your local National Instruments office, please use the following link.
http://www.ni.com/company/worldwide-offices/