The invention discloses an RS trigger. The RS trigger comprises: a resetting/setting RS trigger body; The delay device which is connected with the RS trigger body and is used for performing first delay processing on the first input signal before the first input signal is transmitted to the setting end of the RS trigger body and/or performing second delay processing on the second input signal before the second input signal is transmitted to the reset end of the RS trigger body; wherein the difference between the delay time generated by the first delay processing and the delay time generated bythe second delay processing is greater than a preset threshold value. A worker can determine the signal which is firstly changed into the low level according to the delay time, that is, the level state output by the RS trigger body is determined, and the worker does not need to pre-process the first input signal and/or the second input signal, so that the labor cost and the time cost are saved. The invention further discloses a controller which has the same beneficial effects as the RS trigger.