How do the data manger and data logger interact with a system of multiple inverters?
How many data managers are needed per inverter?
When more than one Fronius is used in a whole solar system the inverters are “daisy chained” together via the RS45 cable. Every Fronius (including the Symo lites) come with the RJ45 socket (IE Ethernet socket). With all the inverters ‘hard wired together’ only one Datamanager is needed to connect the whole system to the internet via wifi or ethernet cable. This system is using the Fronius ‘cloud based’ data processing software.
The data logger is altogether different. The logger is used as a local data manager for large installation which do not want to use the cloud based data manager. Thus the data logger is a local source for the data processing software system.
Solar Edge Communications
Standard SE line includes 3 RS485, and an ethernet port. These ports can be used to connect through a hard wire inverters to other inverters and routers respectively. With hard wires the maximum allowable distances are 330 ft and 3300 ft respectively, due to signal losses. To utilize the RS485 port to daisy chain the inverters, this is done easily with either an Ethernet cord or better a RS485 cable, just cut the ends off and strip 3 of the wires to plug into the B,A,G (the three far left slots) in the RS485 port.
The Zigbee kit can be used to create a wifi connection from up to 15 inverters (with additional “slave cards” needed for each inverter), with a 50ft range in doors and 800 ft line of sight from one inverter to the next. This Zigbee kit includes a home gateway and one slave unit. Each inverter which needs to transmit information wirelessly needs an additional slave unit, but one inverter can transmit all the information for many inverters. Only one home gateway is needed for every 15 inverters.
Alternative to having many slave cards for each inverter, one inverter can have the slave card and the others can be hard wired (or daisy chained) together. Thus, one inverter will communicate wirelessly for the whole group, in this setup you will still have monitoring visibility on each individual inverter.
As a third and last option is the Solar Edge Cellular CDMA Kit. This product uses cellular networks to transmit to the internet the monitoring data. There is a monthly subscription, the first 5 years of which are waived with the purchase, the remaining subscription is $1 per inverter per month and is not likely to increase. The down side here is you need one CDMA Kit per inverter, so the larger the system the less cost effective it is.