It's all pretty simple. In both of your VIs, do you see the AI Config function? This is where the channels are specified and they are configured. The channel list is an array and so is the 'input limits' and 'coupling & input config' inputs. The sound and vibration VI is creating this information with the svx_Get DAQ Info function. Presumably, this will create the channel information for just the s&v channel you are using. To add the voltage channel, just append this information to the arrays created by svx_Get DAQ Info. So, if right now, svx_Get DAQ Info returns a channel array with channel 0 in it, you would append your voltage channel (i.e. 1) to this and have a new channel array with element 0 = 0 and element 1 = 1. Do the same thing with the limits and coupling arrays.
DAQ from NI has always supported multiple channel acquisition. You can have an array of channels or a single element can define multiple channels (i.e. 0:4). When you use a single channel per array element, then you can define a separate limit and coupling for each channle.
If you were to save the Cont Acquistion VI with your default setup, then I could post an example. All you have to do is go to Operate>Make Current Values Default.
