We plan on using a PXI-8433/4 card housed in a PXI-1042 chassis to read data from four RS-485 serial data links. Each of the serial data links we are reading have their own isolated common that is not tied to any other channel's common. Also, the transmitter common and the receiver common for each data link is tied together. Bascially, each of the four serial data links we are reading are completly isolated from each other, but the transmitter and receiver ends for each data link have their commons tied together. Attached is a pictoral representation of our setup.
We found this article about how optical isolation is implemented on other serial acquisition cards:
http://digital.ni.com/public.nsf/allkb/4A380A17DB3D9EF086256C68006F1DCB
This article basically says that the I/O lines are isolated, and the power for the transceiver is isolated through a transformer. Is this how the Transmformer isolation is implemented on the PXI-8433/4 card? We do not want the transceivers in the PXI-8433 card to tie the serial data link commons together. As such, we would need each transceiver to have it's own isolated common, and thus it's own isolated power source. Are each of the transceivers in the PXI-8433 card completely isolated from each other, including their common/reference? Thank you for the help.
