NCD5500 reset IP address problem

We are using the NCD5500 Ethernet to I2C interface. We have used dozens of these devices, all of which have been programmed for static IP addresses. The 5500 has reset itself to DHCP mode on a few occassions - once to 6 NCD5500 devices simultaneously. It seems to happen when there is an electrical event - such as when nearby equipment had a heavy load. The units have a dedicated power supply.

Any idea why the programmed IP address is being lost? Any suggestions for prevention?


We have seen this issue in the past with Hardware Revision 2 boards using firmware version 2.2 or earlier.

Are your Ethernet modules hardware revision 2? You should be able to tell l when using the NCD Config Tool and expanding the devices on the left.

  • Revision 1 hardware will have a device type of NCDWEBI in the NCD Config Tool
  • Revision 2 hardware will have a device type of NCDWEBIV2 in the NCD Config Tool

If you do then this github repo will have instructions for updating the firmware as well as the firmware and config tools you’ll need: GitHub - ncd-io/ncd_Ethernet

As additional information what caused this in earlier firwmares was a rapid power cycling of the Ethernet module will reset to factory defaults.

Heavy loads on inductive loads can cause a voltage spike to feed out into the AC or to nearby devices which in turn can lead to brownouts, restarts, or damage to effected electronics.