RS 485 and Power Limited
The RS 485 serial interface card, placed in the DB9 expansion slot of the RS range of inverters, enables the creation of a serial BUS and Modbus through a PC or a monitoring system with specific software. The RS 485 interface is also required to connect the inverters to the RS Datalogger to centralise the data that will be sent to the supervisory cloud (RS Monitoring).
• connect multiple inverters displaying all the parameters
• connect RS Datalogger for inverter monitoring
• management of ModBus protocol over a half-duplex RS-485 serial line, open source and royalty free. Setting the ModBus address via APP (through inverter Wi-Fi connection)
• No. 2 auxiliary input contacts for remote tripping and external control (required by CEI 0-21)
• Connecting a TA (current sensor) in order to enable the Power Limit Function that forces the inverter to limit the production of energy to the sole need of self-consumption or limit feeding into the grid to a desired maximum value
• Wi-Fi password reset button
RS Datalogger provides a simple and cost-effective solution to achieve the following objectives:
• A datalogger for simply monitoring the inverters in a plant.
• A datalogger for monitoring the inverters of a plant with the function of a power limiter (a digital multimeter is required for this application).
The following diagram shows an example of a system for monitoring inverters via both RS Datalogger RS485-1 and RS485-2 communication ports. A maximum of 20 inverters can be connected to each port. An external sensor can also be connected to the system to measure the radiation and external temperature of the panels. The RS485-2 port must be configured in “Inverter” mode.
Default configuration In the following cases, no changes to the data logger settings are required:
• The system is intended to monitor up to 20 inverters.
• The system is also used to monitor the radiation and temperature of the panels.
• The datalogger's default Modbus parameters are used for communications with inverters via the RS485-1 port:
- Address: 1-20.
- Baudrate: 9600bps.
• The datalogger is connected to a LAN that supports DHCP for automatic IP address assignment.