diff --git a/cfg/sim_mlz_ccidu1_cfg.py b/cfg/sim_mlz_ccidu1_cfg.py
index 8253b2a..d922e1f 100644
--- a/cfg/sim_mlz_ccidu1_cfg.py
+++ b/cfg/sim_mlz_ccidu1_cfg.py
@@ -91,6 +91,7 @@ Mod('ccidu1_V6',
     'frappy.simulation.SimDrivable',
     'Needle valve',
     value = Param(default=99, datatype={"type":"double", "min":0, "max":100, "unit":"%%"}),
+    target = Param(min=0, max=100),
     visibility='expert',
 )
 
diff --git a/frappy/simulation.py b/frappy/simulation.py
index 0b55e82..0b790b0 100644
--- a/frappy/simulation.py
+++ b/frappy/simulation.py
@@ -31,7 +31,7 @@ from frappy.modules import Drivable, Module, Parameter, Readable, Writable, Comm
 
 class SimBase:
     def __new__(cls, devname, logger, cfgdict, dispatcher):
-        extra_params = cfgdict.pop('extra_params', '')['value']
+        extra_params = cfgdict.pop('extra_params', {'value': ''})['value']
         if isinstance(extra_params, str):
             extra_params = [v.strip() for v in extra_params.split(',')]
         attrs = {}