Modbus TCP
SunSpec Model 129 — LVRTD
SunSpec
Overview
SunSpec Model 129 — LVRTD is a standardised SunSpec information model that configures the Low Voltage Ride-Through Disconnect behaviour of grid-tied inverters and other distributed energy resources. The template reads and controls the active curve index, module enable flag, and timing registers (wintms, rvrttms, rmptms), plus the read-only capability registers ncrv and npt and the scale factors tms_sf and v_sf. Using Modbus TCP, the ModbusCloud Gateway polls the device's fixed block at the model's base address, letting operators verify which LVRTD curve is active and confirm the reversion timeout in force. Supported companion models include SunSpec Model 130, Model 137, and Model 138.
Use cases
- Verify which LVRTD curve is active on each inverter after a grid-code change to confirm correct configuration.
- Monitor the modena enable flag across multiple sites to detect inverters where LVRTD has been inadvertently disabled.
- Track the rvrttms reversion timeout to ensure curve changes programmed via SCADA will not silently revert to default.
