Hi!
The TB 2631 attached to a PXI 2530 will let you assume a 4x32 (1-wire) or 4x16 (2-wire) matrix. Connecting to a DMM with a 4x32 1 wire topology you would be able to connect the DMM to the 4 Rows and up to 8 4 wire RTDs to the different columns ( 32/4 =8). You should consider the TB 2630 if 8 is not enough; this terminal block will let you assume a 4 wire 32x1 topology so you could measure up to 32 RTDs from the same DMM with this one switch card. Let me know if anything I said was unclear.
Matt
Applications Engineer
National Instruments