Hi, I am a new user of this forum and normally I use Siemens CPU, but in this case I am using a Allen-Bradley CPU and I need of help to update its firmware. The problem is the follow: In the CPU there is a firmware with version 33xx but my project is made with the version 30xx. So I tried to update the firmware version from " ControlFLASH Plus " but without success, because after few seconds it shows the error " Unable to download ". The question is very easy ... Why ?