Check out the sections "Communication Overview" and "Where is an example to do XYZ?" on the LabVIEW for LJM page:
https://support.labjack.com/docs/labview-for-ljm-windows-macos#LabVIEWforLJM-Windows&macOS-Communica...
To read from multiple inputs of any type, you can just use one call which is LJM_eReadNames. You pass in a list of the inputs you want to read.
To write to multiple outputs of any type, you can just use one call which is LJM_eWriteNames. You pass in a list of the outputs you want to write.
To read from a single input, you can just use one call which is LJM_eReadName. You pass in the name of the input you want to read.
To write to a single output, you can just use one call which is LJM_eWriteName. You pass in the name of the output you want to write.
but I cannot see a separate vi to read or write to a single I/o terminal. Can anyone tell me the relevant vi to call.
Say you want to set the digital channel FIO4/DIO4 to output-high. Looking at the Digital I/O section of the T-series Datasheet, you can see that an easy way to do this is to write a 1 to the channel named "FIO4" or "DIO4" (both do the same thing).
https://support.labjack.com/docs/13-0-digital-i-o-t-series-datasheet#id-13.0DigitalI/O[T-SeriesDatas...
An easy way to do this is to call eWriteName with Name="FIO4" and Value=1.
https://support.labjack.com/docs/ewritename-ljm-user-s-guide
From our LabVIEW for LJM package, you can open "LJM_eWriteName Example.vi" and try this yourself.
