An IO Variable with network publishing enabled will maintain the timestamp from when the IO was acquired when it publishes the value across the network. However, if you read the IO Variable locally and then write it to a separate network published shared variable for publishing on the network, the timestamp won't be maintained. In this case, the timestamp corresponds to when the network variable engine received the point and not when the IO data was sampled. If you're observing something different from this, you should post back so we can try to figure out what's going wrong.
As was mentioned earlier, the IO Variable bases its timestamp on the current system time. Since 1588 synchronizes the system time of multiple RT controllers on the network, it should be possible to accomplish what you want. You'll also have to incorporate a future time event into your application to start all of the applications on the controllers at the same time. Without this, the applications on the different controllers won't be in phase. They shouldn't drift, but they won't be in phase.
