Solis Inverters Internal Topology & Zero Export Fail-Safe Compliance Letter

Subject: This letter serves as official documentation from the manufacturer regarding the internal topology

and zero-export fail-safe mechanisms of the S6-EH2P(9.6-16)K-SV-YD-L-US series intended for installation

within your utility jurisdiction.

1. Internal Topology and Operational Logic

The Solis inverter system operates as a closed-loop Power Control System (PCS). To accurately monitor and

manage the power exchange (import and export) between the premises and the utility grid, the system utilizes

a dedicated external meter paired with ≤ 0.5% accuracy Current Transformers (CTs). These CTs are installed

at the main service entrance.

The external meter communicates site-level energy data back to the inverter's Digital Signal Processor (DSP)

in real-time via a hardwired communication protocol (RS485/Modbus). When the system is configured for a

Zero-Export profile, the inverter's DSP continuously processes these telemetry measurements. It dynamically

curtails Photovoltaic (PV) power generation to strictly match the instantaneous local load demand and, if

applicable, battery charging requirements, ensuring that the net power exported to the utility grid remains at

0kW.

2. Export Power Control Setting

To limit the export power of the system to 0 kW first go to the Storage Mode settings menu within the inverter

settings. The “Allow Export” setting should be changed from Enable to Disable by clicking the field in the Set

Value column and then clicking “Disable”. Lastly, click “Save” just to the right of the field to change the

setting to Disable. Doing this ensures the system does not export any power to the utility.

3. FailSafe Setting in the Event of Meter or CT Failure

The system is equipped with a dedicated, firmware-level “FailSafe” parameter designed specifically to protect

the grid integrity in the event of hardware or communication loss.

Should the external meter experience a hardware failure, or should the communication between the CTs, the

meter, and the inverter be interrupted (e.g., a severed RS485 cable, loss of Modbus polling, or physical

damage to the CTs), the inverter instantly registers a loss of the critical reference signal. Upon this detection,

the programmed FailSafe feature engages immediately.

When the Fail-Safe is triggered, the inverter's control logic systematically shuts down active power output,

throttling PV production to exactly 0kW. The system remains locked in this secure, non-exporting state and

will not resume standard PV production or export until the physical meter or CT communication has been

successfully restored and verified by the system.

The FailSafe setting is located within the “Function Settings” of the inverter. Click the white box in the “Set

Value” column, then click ON, and then click “Save” just to the right of the setting.

4. Official Confirmation

Solis officially confirms and attests that under no circumstances can the aforementioned inverter models

backfeed power into the utility grid in the event of a meter failure, CT failure, or communication loss between

the measuring equipment and the inverter. The internal topology guarantees a default to a 0kW generation

state to ensure absolute grid safety.

Should your engineering team require further technical clarification, please do not hesitate to contact our

product management team directly.

If you have any questions, please reach out to the US Solis Support team for assistance:

email: usservice@solisinverters.com & phone: +1(866)438-8408

Michael Allen, Product Manager

michael.allen@solisinverters.com

Solis North America