diff --git a/main.cpp b/main.cpp
index e702e32..3172089 100644
--- a/main.cpp
+++ b/main.cpp
@@ -353,7 +353,7 @@ int main(int argc, char* argv[])
         ImGui::Text("TEC current: %.3f mA", (float)tec_current*1000.0f);
         ImGui::SliderFloat("Setpoint", &freq_setpoint_local, 0.0f, 40.0f);
         ImGui::SliderFloat("TEC bias", &tec_bias_local, 0.0f, 0.5f);
-        ImGui::SliderFloat("TEC P", &tec_p_local, -1.0f, 1.0f);
+        ImGui::SliderFloat("TEC P", &tec_p_local, -1.0f, 0.0f);
         freq_setpoint = freq_setpoint_local;
         tec_bias = tec_bias_local;
         tec_p = 0.01f*tec_p_local;