At AEE Solar, our preferred PV rapid shutdown devices for use with the Sol-Ark inverters is the AP Systems APsmart RSD-S-PLC module level device and the TRANSMITTER-PLC for the signal transmitter. The RSD-S-PLC module level devices easily clip to the PV module frame, and can be installed and wired to the module while they are still on the ground. The transmitter is mounted near the inverter, and has a toroid that the PV cables pass through and transmits a turn on signal over the PV cables to the module devices. There is no extra wiring to the array needed. With the keep alive signal from the transmitter the module devices turn on, and without this signal the module level devices turn off. Only one wire from each PV circuit can go through the toroid. If you put both positive and negative wires through the toroid they cancel out the signal and the array will not turn on. You can put up to 6 strings through one toroid, or the fit of the wires may limit this to fewer. If you have multiple Sol-Ark inverters, it’s best to use one transmitter per inverter. The transmitter and toroid generally do not fit inside the wiring compartment of the Sol-Ark inverter so a separate j-box or gutter below the inverter is the best place to install it.
Because the APsmart devices are SunSpec compliant they are not interchangeable with the Tigo TS4-A-F devices which are not SunSpec compliant. If you use the Tigo TS4-A-F devices you’ll also need to use the Tigo transmitter. Otherwise the installation is very similar.
The Sol-Ark RSD 12VDC output terminals (#15 and #16) are only rated for 100ma and the APS transmitter (and I think the Tigo transmitter also) can take up to 800ma so the RSD 12VDC output can’t be used to power the transmitter. This means a separate 12VDC power supply is needed to run the transmitter. I suggest using a 48VDC to 12VDC converter power supply for this. Running it from an AC source may not be as reliable if the grid is off or the inverter AC output is off for any reason. You’ll need to install a small fuse or breaker at a 48VDC source from the battery to power the converter. Here’s a link to a 48VDC to 12VDC converter power supply that can be used.
In addition to turning off the PV modules, it’s also necessary to turn off the inverter so it does not back feed the PV circuits with voltage. This is done by closing a contact between two terminals (#11 and #12) in the inverter. For complete PV shutdown you need to open the contacts to the transmitter and at the same time close the contacts to turn off the inverter. There is a specific IMO BG10P34-11 button that has both NO and NC contacts so it can be used to shut down both the PV transmitter and the inverter.
Here are the three main devices needed from AEE Solar. You’ll need one RSD-S-PLC per PV module, one TRANSMITTER-PLC for each Sol-Ark inverter and one IMO switch.
- 300-00251-21 APS, RSD-S-PLC, RAPID SHUTDOWN UNIT
- 300-00252 APS, 406001, SINGLE CORE TRANSMITTER-PLC, 12VDC, RAPID SHUTDOWN TRANSMITTER UNIT
- 300-00253 IMO, BG10P34-11, RAPID SHUTDOWN INITIATOR SWITCH, NO-NC CONTACTS, OUTDOOR RATED, UL LISTED
This is a diagram for the preferred method of using the AP smart RSD with the Sol-Ark inverter.
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Written by: Brad Bassett, AEE Solar Sr. Applications Engineer
