Hi @qy2009 I have dealt with people running into issues whilst trying to use this component, but they seem to come through in the end, and get it working…I am seeing some slight syntax differences from how you are trying to read the value to how I have it documented in the link in the above post to my github page. I will attempt to get PSU running on my wifes laptop tomorrow and post a full on solution, if the demo files in the documentation are not working, as that was written for UD not PSU, so some slight adjustments might be required…I cannot promise this though as I also got four daughters to entertain tomorrow as well 
Not sure if the code I got in this post will help?