If the serial-port LED on your ioLogik E2000 lights up or blinks even though no serial devices are connected to it, this could be because of a voltage leak from the DIN rail on which the device is mounted. The voltage leak may flow through the serial port causing the serial-port LED to turn on or blink.
There are two ways to fix this issue:
- Ensure that the DIN rail is well grounded.
- Isolate the ground (GND) wire of the ioLogik E2000 serial port from the GND of the DIN rail. You can stick a piece of insulation tape on the DIN rail where the two GNDs might come into contact. This will prevent the voltage leak from the DIN rail from flowing through the ioLogik E2000 serial port’s GND.