Danfoss VLT Series Design Manual page 153

VLT ® HVAC Drive Design Guide
7.9.2. Storage of Data
The 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 (coil 65 = 0).
7.9.3. IND
The array index is set in Holding Register 9 and used when accessing array parameters.
7.9.4. Text Blocks
Parameters 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 request for a parameter is for more characters
than the parameter stores, the response is truncated. If the read request for a parameter is fewer
characters than the parameter stores, the response is space-filled.
7.9.5. Conversion Factor
The different attributes for each parameter can be seen in the section on factory settings. Since
a parameter value can only be transferred as a whole number, a conversion factor must be used
to transfer decimals. Please refer to the
7.9.6. Parameter Values
Standard Data Types
Standard data types are int16, int32, uint8, uint16 and uint32. They are stored as 4x registers
(40001 – 4FFFF). The parameters are read using function 03HEX "Read Holding Registers." Pa-
rameters 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 Types
Non 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).
7.10. Examples
The following examples illustrate various Modbus RTU commands. If an error occurs, please refer
to the Exception Codes section.
7.10.1. Read Coil Status (01 HEX)
Description
This function reads the ON/OFF status of discrete outputs (coils) in the adjustable frequency drive.
Broadcast is never supported for reads.
Parameters section
MG.11.B4.22 - VLT ® is a registered Danfoss trademark.
7. RS-485 Installation and Set-up
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