diff --git a/models/AbstractModel.py b/models/AbstractModel.py
index 3ce8b03..1a16dcb 100644
--- a/models/AbstractModel.py
+++ b/models/AbstractModel.py
@@ -78,8 +78,8 @@ class AbstractModel:
         if key not in self.DEFAULT_VALUES.keys():
             raise ValueError("Given key is unknown!\n"
                              "Please check spelling and refer to list LIFAC.KEYS.")
-        if "tau" in key and value < 0:
-            warn("Time constants cannot be negative! Setting it to 0.5ms")
+        if "tau" in key and value <= 0:
+            warn("Time constants cannot be zero or negative! Setting " + str(key) + " to 0.5ms")
             self.parameters[key] = 0.00005
             return
         self.parameters[key] = value