Meter Comms: MET_Comm-Fail, CT-Fail, Fail-Safe

Every inverter comes with an energy meter included. This meter gets installed external to the inverter, within the main service panel. There are two CTs that connect to the meter which go around the L1 and L2 conductors joining the utility meter with the main service panel. 


Note: Page 53 of the Solis S6 HV Home Energy Storage Inverter shows and explains where the external meter + CTs must be installed for the system to operate normally.


CT-Fail alarm

This alarm will occur if the CT wiring is loose. It can also occur when the inverter is on older firmware.

Troubleshooting Steps:

1. Check the wiring between the CTs and the meter, make sure no connections are loose.

2. If that does not clear the alarm, escalate to L2

3. L2 should update the inverter firmware both HMI and DSP

4. Once the inverter is updated, wait about five to ten minutes for the alarms to clear. If someone is on-site, have them power cycle the inverter after the update is done. Turn off both AC and DC power to the inverter until all LEDs turn off. Then turn the inverter back on.

5. If the alarm does not clear, then escalate to L3.


Fail-Safe alarm

This alarm occurs when the Fail-Safe setting is set to Enable (ON) and the inverter has poor communication with the meter. This alarm will typically occur in tandem with the MET_Comm-Fail alarm. Follow the troubleshooting steps below for MET_Comm-Fail. Disable the Fail-Safe setting if you do not want the inverter to shut off when it loses communication with the meter. This setting is to prevent the inverter from exporting power if meter communication fails.


MET_Comm-Fail alarm

When the MET_Comm-Fail alarm occurs, the inverter is not communicating successfully with the meter.


1. Check the inverter and the meter to make sure they are both powered on. The meter lights will be lit up if the meter is getting power. It needs 240VAC from a 2-pole breaker in the main service panel.

2. Make sure that the brand of the meter installed matches the brand of the meter selected. It will either be Chint or Acrel, and the wrong one being selected will cause these alarms to occur. Change the meter model if you need to to clear the alarms. 

3. Turning the Fail-Safe setting to disable (off) will stop the inverter from shutting off due to there being communication issues with the inverter. To stop the alarms completely, set the meter model to "No Meter".

4. Check the RS485 connection between the meter and the inverter. Make sure that RS485A is the same color on both ends, same for RS485B. 

5. Remove the RS485 wires from the terminals, check to make sure there is plenty of bare wire exposed, and then reinsert the wires into the terminals. Do this at the meter end and the inverter end. 

6. Ensure the RS485 cable is not being run in the same conduit as any high-voltage conductors. 

7. Connect to the inverter with the SolisCloud Bluetooth tool. Go to Settings, then Advanced Settings, and then Meter Settings. 

8. If the meter is installed properly and the settings are configured correctly but the alarms are persistent, please escalate to L2.

9. L2 will remotely update the inverter firmware. If the alarms do not clear after the firmware updates, L2 will escalate to L3. 


Below and attached is the troubleshooting flow chart for meter communication issues.


M
Michael is the author of this solution article.

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