diff --git a/plugins/Eiger.java b/plugins/Eiger.java
index 7cac057..2063ff0 100644
--- a/plugins/Eiger.java
+++ b/plugins/Eiger.java
@@ -419,7 +419,7 @@ public class Eiger extends Panel {
             if (stddaq!=null){
                 int images = (Integer)spinnerImages.getValue();
                 String file = textFile.getText();
-                evalAsync("std_daq.start(n_images=" + images + ", output_file='" + file + "')");
+                evalAsync("std_daq.start(" + images + ", '" + file + "')");
             }
         } catch (Exception ex){
             showException(ex);
diff --git a/script/devices/StdDaq.py b/script/devices/StdDaq.py
index b27c67a..9381cc7 100644
--- a/script/devices/StdDaq.py
+++ b/script/devices/StdDaq.py
@@ -20,7 +20,7 @@ class StdDaq(DeviceBase):
     def doInitialize(self):   
         pass 
                 
-    def start(n_images, output_file):
+    def start(self, n_images, output_file):
         self.state.assertIs(State.Ready)
         if not self.simulated:
             data = {"sources":"eiger", "n_images":10, "output_file":"/tmp/test.h5"}