Dear Bart,
You can use the Labview function NI Switch relay control.vi to control the reference relays, with relaynames. When closed these relays connect a reference input with a row.
Reference input 1 with input name 1WREF0 can be connected to row(bank) 1 with relay kref01
Reference input 2 with input name 1WREF1 can be connected to row(bank) 3 with relay kref23
Reference input 3 with input name 1WREF2 can be connected to row(bank) 5 with relay kref45
Reference input 4 with input name 1WREF3 can be connected to row(bank) 7 with relay kref67
You can find the relaynames in the NI Switch Help File when you search for: 'NI PXI-2530 Independent Topology' (Document has the same title)
Please let me know if you have more questions.
Best regards,
Bas van Dijke
AE, Netherlands
