diff --git a/geomagio/Controller.py b/geomagio/Controller.py
index 6cd3ae81d76c06c4fa73ad422f9aef2908a1d6e4..1b9ce45c0d6d690c6cdcc2dc5a0c7d8fa2cbdab2 100644
--- a/geomagio/Controller.py
+++ b/geomagio/Controller.py
@@ -73,7 +73,7 @@ class Controller(object):
                     start=starttime,
                     end=endtime,
                     observatory=obs,
-                    channel=channels)
+                    channels=channels)
             timeseries += self._inputFactory.get_timeseries(
                     observatory=obs,
                     starttime=input_start,