P1 AURORA CENTRAL RTU Modbus Specification (3I56001F000G) (Related Firmware Version C012) March 2012, Version 1 Rev 13 This document is confidential to the organisation receiving it Neither the document nor the information contained in it may be revealed to any third parties without an approval from P1’s executive management P1 reserves the right to change any information in this specification without advise By Power One Italy Page of 27 2 THE MODBUS PROTOCOL In the our Modbus Interface is implemented only the RTU Mode The parameters are referred to as 16-bit Modbus Registers, a 32-bit Float parameters covers therefore two Modbus registers The broadcast mode is not allowed An implemented subset of the Modbus functions contains: • O3 Read-Write Holdings Registers • 04 Read Input Register The communication foresees the following setting: • RS 485 • Baud Rate 19200 bps • 1 bit start • 1 bit stop • No parity • 8 data bits (RTU protocol) The Modbus Interface collects data by max 32 Aurora Central Inverters The Modbus Interface collects data by max 64 Junction Box The Modbus Interface collects data by max 16 Rack Is recommended before to use this Modbus Interface to have already setting the values of the Racks Numbers in the System By Power One Italy Page of 27 3 READ OUTPUTS REGISTERS (Rd 03/Wr 06-16) This function allows to require the value of 16-bit register containing Modbus Address parameter This function allows also to change this parameter via command 06 , the value changed is saved in EEprom memory The Default parameter is 0x01 Register Map Add Word Description Unit Format 0001 1 Modbus Address Decimal (1-247) Unsigned int This function allows to synchronize Modbus collection Data (Junction Box and Rack) Is recommended to use this feature every day at the start of the system to synchronize the data acquired The parameters accepted are: 1 = Synchronization This register show also the answers at the Modbus Synchronization command 9999 = Synchronization Pending Register Map Add Word Description Unit Format 0002 1 Modbus Synchronization Decimal Unsigned int