I'm working with RsLogix v6.10 and notice that AB's documentation states, as it has for many years, that the RTO timer behaves as the TON timer except for the RES and ACC functions. My experience contradicts this, as the TT bit remains set until the ACC reaches the Preset or the timer is Reset, in the emmulator software, if the time rung is true or false. This is NOT like the TON. Is this a result of legacy documentation in need of update due to a change in PLC or software functionality. AB support didn't seem to know or care, when called.