My principle question to understand the outputs of the PV780:
Can these outputs only be activated by using timers to control or can a variable value be used to set a output on or off?

In PowerVision 2.8 and a PV780 actions are used to set the digital output high or low and also to set the output frequency.

On the Connections page the Digital Output and Frequency Output are enabled by having associated variable names. The actions for the IO channels look like this:

IO->Digital Output High(Digital Output)

IO->Digital Output Low(Digital Output)

For the frequency output the variable is the frequency value, such as IO.Frequency Output variable would have the frequency value and the action is:
IO->Frequency Update(Frequency Output)