the MLT circuit is derived from the dual timer board. there are two potentiometers on the dual timer board, one for the TA relay for transferring to delta in a wye-delta system, and one for the MLT timer. both timers are activated by the normally open UA contact feeding the board. when the timer for MLT expires, the board outputs a ground signal to the appropriate input board terminal. there is also a low oil switch that can be added that when closes sends a ground signal to the same input board terminal as the timer does. I am not sure, but there may have been some early omega 1000 that had a MLT that was generated by software. If you have an input called MLT, then it is not software generated.