Sync to line freq

I’m wondering if there is a technique for syncing with the line frequency so that when I operate my AC solenoids, I can sync them for minimum jitters (zero cross lag)


There is no built-in technique. You could possibly use an analog input with a reduced AC signal (transformed lower or voltage divider) and make a user program that checks for the zero-crossing. Another option is to reduce the AC signal and rectify it, then use a discrete input to give every other zero crossing.
Once the program finds a zero crossing, it would have to somehow sync with the program that is turning on the RMC’s discrete output, as well as compensate for the lag between the RMC’s discrete out and the external AC relay you are using.