Communication between inverter and smart energy meter has been lost or is intermittent. The inverter cannot read the meter — G100 export limiting will not function and the inverter may default to zero export.
Common causes
Loose or damaged RS485 communication cable between inverter and meterMeter RS485 address or baud rate mismatch — DTSU666-20 factory default is address 1, baud rate 9600bpsRS485 cable run exceeds 10m without termination resistor — add parallel resistor at meter endIncorrect termination of RS485/meter communication wiringMeter has no power — check meter display is active
What to check
STEP 1
Check the meter display is lit and showing readings — if blank, the meter has no power. Then inspect the RS485 communication cable: check for damage, loose plugs, or pulled connections at both the inverter COM port (A2/B2 terminals) and the meter A/B terminals. Ensure cable is securely seated and polarity is correct (A to A, B to B).
STEP 2
If cable looks fine, check meter programming: DTSU666-20 default is Modbus address 1, baud 9600bps, N.8.1. Verify these match the inverter's meter settings in iSolarCloud. If RS485 cable run is over 10m, a parallel termination resistor must be installed at the meter end. Disconnect and firmly reconnect communication cable.
Escalate if
Cable intact, meter powered, address and baud confirmed correct — alarm persists. Contact Sungrow support.
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