Modbus RTU

KOSTAL solar inverters, but also other devices, can be connected to the Modbus RTU RS485 interface.

In Modbus RTU Slave mode, the KOSTAL Smart Energy Meter provides the measurement data via the RS485 interface. However, in Modbus RTU Master mode, measurement data is sent and written to other slave devices in order to control them. Master mode is only possible via user-defined settings.

Both RS485 interfaces A and B can be configured individually.

INFO

You will find details of how to connect the communication cable from the inverter to the RS485 socket in the KOSTAL Smart Energy Meter's installation instructions.

Depending on the cable length and number of participants on the bus, we would recommend terminating the bus at both ends with a 120-ohm resistor. Termination reduces reflections in the connection. Under certain circumstances, this may be absolutely essential for application reliability.

When an inverter is selected for RS485 interface A or B, all fields are populated with predefined values. These can be adapted if necessary.

Settings for Modbus RTU via RS485

Parameter	Explanation
Interface	RS485 (A) Pre-configured for PIKO IQ/PLENTICORE RS485 (B) Pre-configured for PIKO MP plus
Enable interface	Activated The Modbus - slave functionality on the respective RS485 interface is activated. Data can only be retrieved from the KOSTAL Smart Energy Meter via the interface once the interface has been activated and the settings have been saved. Deactivated The Modbus interface is deactivated. NOTE! When using a PIKO MP plus with a connected battery or an ENECTOR wallbox and enabled convenience functions, you will need to deactivate the interface here. You are asked to do this when setting up the battery or the wallbox in the setup menu for the devices.
Presetting	Selection of connected device. When a device is selected, all fields are populated with predefined values. These can be adapted if necessary.
Mode	Slave (default)/master The interface operates either as a Modbus master (data is sent and written to slave devices) or as a Modbus slave (only data which can be accessed from other devices is made available).
Slave address	Defines the address of the Energy Manager in the Modbus The value may be between 1 and 247.
Baud rate	Defines the baud rate of the connection
Data bits	Defines the number of data bits
Parity	Defines the parity of the connection
Stop bits	Defines the number of stop bits