diff --git a/frappy_psi/ls370res.py b/frappy_psi/ls370res.py
index 14bb917..bad3221 100644
--- a/frappy_psi/ls370res.py
+++ b/frappy_psi/ls370res.py
@@ -68,8 +68,8 @@ class LakeShoreIO(HasIO):
             args.insert(0, cmd)
         else:
             args[0] = cmd + args[0]
-        head = ','.join(args)
-        tail = cmd.replace(' ', '?')
+        tail = ','.join(args)
+        head = cmd.replace(' ', '?')
         reply = self.io.communicate(f'{head};{tail}')
         return parse_result(reply)