We are using Serial COM port to get a data from serial device (load cell). Using "serial" node we are getting data. In random scenario "serial" node getting timed out. And getting empty string. After resetting the serial device we are getting values from "serial" node. If we are using hyperterminal tool, we are able to getting the data continuously.
Have you set the settings of the serial port correctly when working with Node-RED? Perhaps compare the hyperterm settings with the node-red serial settings.
Also, what settings have you given the node for the input?
I would recommend to change the serial node config for troubleshooting purposes. You would have a clear visibility of the data received from the device using config below. Check the binary data in a debug node.