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How to fix a modbus communication issue?

No Modbus communication

Product Line:
All GTxxx series


Modbus setting, CCU, fiber optic cable, ICP or Moxa

Note: The work instruction provided is meant for those who are qualified to work on the inverter. This means that they should know how to properly Lock out and Tag Out (LOTO) the inverter..., etc.

If the monitoring system cannot see the inverter then there are a few possibilities. It is possible that the CCU experienced power loss and when it recovered, it was reset to factory defaults. In that case, you need to press the Menu and the Enter button. When it asks for a password on the screen, enter number 594, and then hit enter once. Use the down arrow on the keypad to navigate to Modbus Address and Modbus on\Off. Change Modbus on\off value from 0 to 1 (On). Also, change the Modbus address to the value that your company uses.

Also, make sure that the orange & blue fiber optic cable is properly connected to the CCU board. Skipping the first two ports from the left-hand side, the cables should connect as Orange, Blue, Blue and Orange. If this is all correct and the monitoring is still not working, remove the fiber cable and shine light into one end of the orange cable. You should see light on the other end of the orange cable. Do the same for the blue cable. If you do not see any light or just a small amount of light, the fiber inside the cable is broken.

If everything checks out correctly and the monitoring is still not working, check your monitoring system. If that is working fine, call 866-519-1470 and select option 3 and 3 to get to solar 3phase and open a ticket. 
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