diff -r c2020b2fdd05 -r 93b6b945d939 scc_access/scc_access.py
--- a/scc_access/scc_access.py	Fri Dec 15 22:53:17 2017 +0200
+++ b/scc_access/scc_access.py	Wed Jan 10 17:58:15 2018 +0200
@@ -154,7 +154,7 @@
     def download_optical(self, measurement_id):
         """ Download optical files for the measurement id. """
         # Construct the download url
-        download_url = self.download_optical.format(measurement_id)
+        download_url = self.download_optical_pattern.format(measurement_id)
         self.download_files(measurement_id, 'scc_optical', download_url)
 
     def download_graphs(self, measurement_id):
@@ -495,7 +495,7 @@
     parser = argparse.ArgumentParser()
     parser.add_argument("filename", nargs='?', help="Measurement file name or path.", default='')
     parser.add_argument("system", nargs='?', help="Processing system id.", default=0)
-    parser.add_argument("-c", "--config", nargs='?', help="Path to configuration file")
+    parser.add_argument("-c", "--config", help="Path to configuration file")
     parser.add_argument("-p", "--process", help="Wait for the results of the processing.",
                         action="store_true")
     parser.add_argument("--delete", help="Measurement ID to delete.")