how to compare for just one time in simulink

in my circuit in simulink i have to compare the current with a constant and if this current is above some value it would disconnect one resistor but when this happens the current will be under the value spicified and the resistor is connected and it stays between connecting and disconnecting all the time of simulation . i wonder how to compare for just one time and keep the same value of the output signal from the compare to constant block after the comparision

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Please delete this duplicated question.