In this case you can use the FPScript-function ValuesInInterval and the Index Operator.
– Calculate the indices of the values between -5 and 5.
– Set the y-values of these indices to 0.

Dim Sig = Tension
Sig.Y[ValuesInInterval(Sig, -5.00000000000000, 5.00000000000000, EVENT_INDEX)] = 0
Sig

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