diff --git a/script/RobotSC.py b/script/RobotSC.py
index 22e138b..380a7a3 100644
--- a/script/RobotSC.py
+++ b/script/RobotSC.py
@@ -44,7 +44,7 @@ class jf6(ReadonlyRegisterBase):
         return  None if robot.joint_forces == None else robot.joint_forces[5]
 class jfc(ReadonlyRegisterBase):
     def doRead(self):
-        return  None if robot.joint_forces == None else robot.joint_forces[1] * robot.joint_forces[2] * robot.joint_forces[4]
+        return  None if robot.joint_forces == None else (robot.joint_forces[1] * robot.joint_forces[2] * robot.joint_forces[4])
 
 add_device(jf1(), force = True)   
 add_device(jf2(), force = True)