That Input/output error is a generic one that means the serial port has disappeared from under the driver for some reason when it's trying to communicate with the device. Kernel log from that time might show if the device has reset itself for some reason (there is a watchdog in the ScopeDome controller that might be overly eager) or something else. Also having driver debug enabled in Ekos logging configuration before connecting to the device would show all serial port traffic the driver sends and responses it gets from the device.