Your inverter uploads data to your monitoring platform by communicating with the internet via two little white or black plugs called powerline communicators, or PLCs. One PLC is plugged into an outlet and connected to your router with an ethernet cable. The second PLC is plugged into an outlet near your inverter and is also connected to the inverter by a different ethernet cable.

From left to right: ZyXEL, TP Link, SunPower PLC

How to read your PLCs

There are three LED indicators and a Pair Button on your PLC (there is no pair button on black SunPower PLCs).

Power — Solid Light: PLC is recognizing power source

Ethernet — Solid Light: PLC is connected through Ethernet cable

Communication — Blinking Light: Communication between both PLCs

Pair Button (2 functions): Pressing the button searches for PLC. Holding for 30 seconds triggers a hard reset (PLC forgets PLCs it’s communicated with in the past).

Troubleshooting Problems with your PLCs

1. Communication Light (middle light) is out


Sometimes, the communication between the two PLCs is interrupted and monitoring fails. Below are some troubleshooting steps to restore communication between PLCs.

First, let’s confirm that your system is operating and the problem is just with the internet connection or monitoring site that reports your production. To confirm your system is operating, please check your inverter for any error message or red lights. There should be a solid green light while the sun is shining. Visit the inverter page to fix any error messages or red lights.  If you’re all set, proceed to the next steps.

  • Remove both PLCs from their outlets and disconnect them from the ethernet cables.
  • Plug them into the same wall outlet (see photo).
  • Press the pair (encrypt) button on one PLC and then press pair/encrypt on the other. If you have black SunPower PLCs with no pair button, simply leave them plugged into the same outlet.
  • When the middle lights on both PLCs are illuminated, they are communicating and can be returned to their respective outlets and ethernet cables.
  • Be sure that the PLCs are plugged directly into a wall outlet, not an extension cord or power strip as this allows them to communicate more directly.

2. The Ethernet Light is Out

Check that all ethernet cables are plugged fully into their units. If the cable is connected, but the light is still not turning you, you may have to replace your ethernet cable.


3. There’s no power to the PLC

If NO lights are turning on, you have a hardware error. Please email for further assistance.

Things to Keep in Mind

Whether your monitoring is working or not does not affect how you are credited by your utility for solar production. This is facilitated by your production meter which is tied directly to your utility meter.

If you have GMP, VEC, or WEC, you can view solar production on your utility’s website when you log into your account – the utility has revenue grade monitoring and doesn’t rely on an internet connection, making the data more reliable.

Your monitoring will not show production at night because your inverter shuts down when the sun goes down.


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