What Is The Max Expansion For columns For The PXIe-2532B?

Issue Details

I have a PXIe-2532B and try to expand the terminals through the columns. I have read the articles from the website about the PXIe-2532B and found that it supports different Terminal Blocks (TB) to expand the columns.  However, none show the maximum amount of TBs I can use to extend the columns. Is there a limitation to it? Or can I expand as many as I want to?

Solution

There is no theoretical limit in the hardware, but, in practice, the expansion will reduce the switch matrix's ability to carry signals until it no longer meets the application's requirements.

Each connected module adds capacitance and leakage current to the connected columns, which reduces both the ability of the switch system to pass through AC signals and step functions and its ability to pass through DC signals.

If you do not use the terminal blocks' built-in protection resistance, this additional capacitance will lead to in-rush currents that will greatly increase the chance of relays failing (welding shut) while hot switching - and any relay operation might be hot switching due to the charge left on the capacitance. If you do use the protection resistance, you can minimize this risk, but that resistance plus the capacitance now reduces your available bandwidth even more.