These days most GT PV inverters transmit keep-alive for RSD.
In the case of SMA, they require 5V from the PV string, so a certain number of RSD modules in series, to power the transmitter. Others might get it from AC or from a battery.
Some inverters like SolArk provide power to an external transmitter.
Here's Tigo's transmitter. You could use it to wake up the string, but you don't want it and an inverter's internal transmitter both operating at the same time, might interfere.
The Tigo RSS (Rapid Shutdown System) Transmitter completes the cost-effective rapid shutdown system architecture when paired with Tigo's UL-certified Fire Safety solutions - including the TS4-A-F (add-on), TS4-A-2F (add-on for two modules). The RSS Transmitter sends a signal via PLC (Power Line...
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