diff --git a/src/DiscretePIDs.jl b/src/DiscretePIDs.jl
index 74ff495..157311e 100644
--- a/src/DiscretePIDs.jl
+++ b/src/DiscretePIDs.jl
@@ -75,7 +75,11 @@ function DiscretePID(;
     0 ≤ b ≤ 1 || throw(ArgumentError("b must be ∈ [0, 1]"))
     umax > umin || throw(ArgumentError("umax must be greater than umin"))
 
-    ar = Ts / Tt
+    if Ti > 0
+        ar = Ts / Tt
+    else
+        ar = zero(Ts / Tt)
+    end
     ad = Td / (Td + N * Ts)
     bd = K * N * ad
 
diff --git a/test/runtests.jl b/test/runtests.jl
index 77b45a9..37d0f14 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -144,10 +144,10 @@ res2 = lsim(P, ctrl, 3)
 
 # plot([res, res2], plotu=true)
 @test maximum(res2.u) == umax
+@test pid.I == 0.0
 
 
 @test DiscretePID(Ts=1f0) isa DiscretePID{Float32}
 @test DiscretePID(Ts=1.0) isa DiscretePID{Float64}
 
-
-end
\ No newline at end of file
+end