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Solis Cloud Datalogging Alongside Juggle G100 Inverter Control

Solis Cloud Datalogging Alongside Juggle G100 Inverter Control. Our G100 control solution is controlling (ramping) the inverters, as well as providing the reverse power relay functionality.

Controlling inverters to stay within G100 limits involves writing to them at e.g. 1 or 2 second intervals, to give them up to date percentage limitation values.

This is done over RS485 using Modbus/RTU.

Modbus/RTU only allows for one "modbus master", as RS485 is implemented as a data bus. When the modbus master sends a message, all the inverters will receive the message, but will only act on messages intended for them (based upon their address). If two modbus masters are on the same RS485 network, both will attempt to communicate at the same time, creating unreadable noise on the network. As a consequence, RS485 is designed to only support one Modbus master device.

The G100 controller is one modbus master, which is making quite heavy use of the RS485 network. As soon as a second modbus master (the Solis data logger) is introduced to the same RS485 network there is conflict on the RS485 bus, as both masters attempt to communicate at the same time. This is especially true where one of the devices is communicating at high frequency, such as the G100 control PLC.

The consequence is that the G100 controller is "drowning out" any read requests by the Solis data logger, however in turn the Solis data logger will also be interfering with the G100 control (only on a lower level, probably not enough to cause nuisance trips).

This is simply a consequence of how RS485 works, so there is nothing that can be done in terms of changing the behaviour of the RS485 network.

Juggle "Universal Gateway"

We do have a solution that will solve this problem, which is our "universal gateway". This acts as a gateway between the two modbus masters (G100 & Solis data logger) and the RS485 network that the inverters sit on. This gateway queues any requests & responses between the two modbus masters and the inverters, preventing unreadable noise on the network, allowing two modbus masters to sit alongside each other.

If you would like a quote for this solution, please contact support.