In a program I allow the user to choose AI-channels from a PXI-4461 and a PXI-4462 module.
At first I configured every channel directly after selection; this causes an error when channels from two different modules are chosen. The error message states that for a task with "mixed channels" the acquisition rate and several other properties (not related to the "vertical" settings) should not be configured before all channels are added.
To solve this, I modified the program and just configured the channels with the VI 'DAQmx Ctreate Virtual Channel (AO-Voltage-Basic) (4833)', followed by a 'DAQmx Channel' property node with the property 'AI>>General Properties>>Input Configuration>>Coupling'.
Again, I got the same error.
By trial and error I found that the selection of "mixed channels" is working, when one applies the VI 'DAQmx Ctreate Virtual Channel (AO-Voltage-Basic) (4833)' only. The coupling can be configured later, when the selection of channels is completed.
I found this a bit strange, because the Coupling config is just related to the vertical settings. At least the text in the error message is not completely correct and is misleading because the un-allowed configuration of 'Coupling' is not mentioned. Please, correct this text in a future release; it will prevent users like me puzzling what is wrong.
On the other hand: is this intended behavior or is it a bug? I would expect that if the Input-range and Terminal Configuration can be configured, the Coupling can be done as well.
Thanks for your time,
best regards,
Fred Schimmel
