Hello Rob,
When IP1 receives a one shot pulse from a manual push button, output 13 is supposed to go high (LED on). This high state will be used to drive a relais. This relais is used to enable/disable an injector. so, the injector can now receive current pulses. the number of applied current pulses will be counted by IP2.
So, the arduino only counts, and will disable its output, when programmed count is reached. But it does not produce the pulses. It only needs to count, and reset.
Is this clear to you? Is this difficult to programm?
Thanks, Regards, Theo