diff --git a/models/AbstractModel.py b/models/AbstractModel.py
index 95b907e..3ce8b03 100644
--- a/models/AbstractModel.py
+++ b/models/AbstractModel.py
@@ -1,5 +1,6 @@
 
 from stimuli.AbstractStimulus import AbstractStimulus
+from warnings import warn
 
 
 class AbstractModel:
@@ -77,6 +78,10 @@ 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")
+            self.parameters[key] = 0.00005
+            return
         self.parameters[key] = value
 
     def _set_default_parameters(self):
@@ -87,3 +92,7 @@ class AbstractModel:
             if k not in self.DEFAULT_VALUES.keys():
                 err_msg = "Unknown key in the given parameters:" + str(k)
                 raise ValueError(err_msg)
+
+            if "tau" in k and params[k] < 0:
+                warn("Time constants cannot be negative setting" + str(k) + "0.5ms")
+                params[k] = 0.00005