I have setup with the Nano, and I am experiencing the same basic problem. After the first cycle in which all functions (drop valve, camera shutter and associated led’s) perform satisfactorily, I get a popup window that “no reply received from drop controller” upon clearing that message, the loop timer will time out and another cycle starts, however, the only thing that functions is the green (active) led. no drops are released and camera shutter does not operate and the same warning again pops up. I have slowed the receive and transmit buffer speeds on the com port several times without any improvement in the running of the application. With the installation of the new Nano, I have updated the IDE to 1.8.5. I have also had the Nano plugged into several usb ports and all function the same.