11.9 How to Access Parameters11.9.1 Parameter HandlingThe PNU (Parameter Number) is translated from the register address contained in the Modbus read or write message. The parameter number is translatedto Modbus as (10 x parameter number) DECIMAL.11.9.2 Storage of DataThe Coil 65 decimal determines whether data written to the adjustable frequency drive is stored in EEPROM and RAM (coil 65 = 1), or only in RAM (coil65 = 0).11.9.3 INDThe array index is set in Holding Register 9 and used when accessing array parameters.11.9.4 Text BlocksParameters stored as text strings are accessed in the same way as the other parameters. The maximum text block size is 20 characters. If a read requestfor a parameter is for more characters than the parameter stores, the response is truncated. If the read request for a parameter is fewer characters thanthe parameter stores, the response is space-filled.11.9.5 Conversion FactorThe different attributes for each parameter can be seen in the section on factory settings. Since a parameter value can only be transferred as a wholenumber, a conversion factor must be used to transfer decimals. Please refer to theParameters section.11.9.6 Parameter ValuesStandard Data TypesStandard data types are int16, int32, uint8, uint16 and uint32. They are stored as 4x registers (40001–4FFFF). The parameters are read using function03HEX "Read Holding Registers." Parameters are written using the function 6HEX "Preset Single Register" for 1 register (16 bits), and the function 10HEX"Preset Multiple Registers" for 2 registers (32 bits). Readable sizes range from 1 register (16 bits) up to 10 registers (20 characters).Non standard Data TypesNon standard data types are text strings stored as 4x registers (40001–4FFFF). The parameters are read using function 03HEX "Read Holding Registers"and written using function 10HEX "Preset Multiple Registers." Readable sizes range from 1 register (2 characters) up to 10 registers (20 characters).11 RS-485 Installation and Set-up FC 300 Design Guide11-18 MG.33.BC.22 - VLT® is a registered Danfoss trademark11
