The SYS LED reflect the status of the internal core circuits as well as the host port communication.

A color red SYS LED indicates one of the following possibilities:

• The host port receive FIFO is overflowed.
  • In this situation, you transmitted data/commands are being lost/dropped
  • You must throttle the data going to the device.
• The host port transmit FIFO is over flowed. Happens when the transmit port’s speed is too slow (happens in serial mode).
  • In this situation, you receive data and port statuses are being dropped/lost.
  • Increase the transmission rate or change to Ethernet.
• When in serial mode (RS-232/422), the host’s serial port is not getting the correct data – data fail parity, not the right rate, etc…
  • Correct the port’s settings (baud rate, data size, parity & stop bit).
• The internal watchdog has timed-out.
  • The system will automatically restart in 5 seconds or less.

The blanking indicates data activity.