It sounds like the Cartessa gate controller that we use here, running the NBL cadence. If it is a Cartessa, you can get your impulse directry from the gate controller. The DIN socket on the front of the gate controller can feed a relay that will give you your start impulse. There is a post describing the correct wiring and building of the relay.
http://timingguys.com/eve/forums/a/tpc/f/9716019411/m/8...=877107828#877107828
We have been using the relay that I built for several seasons without any failures.
If it is not a cartessa controller then there still is the possibility for an electronic solution but you would have to cook it up from the power to the valve for the main piston.