Design Guide | VLT® AutomationDrive FC 360
For information on the parameters, size, and conversion index, see the programming guide.
9.9.2 Storage of Data
The coil 65 decimal determines whether data written to the drive is stored in EEPROM and RAM (coil 65 = 1), or only in RAM (coil 65 = 0).
9.9.3 IND (Index)
Some parameters in the drive are array parameters, for example parameter 3-10 Preset Reference. Since the Modbus does not support
arrays in the holding registers, the drive has reserved the holding register 9 as pointer to the array. Before reading or writing an array
parameter, set the holding register 9. Setting holding register to the value of 2 causes all following read/ write to array parameters to be
to the index 2.
9.9.4 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 for fewer characters than the parameter stores, the response is space filled.
9.9.5 Conversion Factor
A parameter value can only be transferred as a whole number. To transfer decimals, use a conversion factor.
9.9.6 Parameter Values
Standard data types
Standard data types are int 16, int 32, uint 8, uint 16, and uint 32. They are stored as 4x registers (40001–4FFFF). The parameters are read
using function 03 hex read holding registers. Parameters are written using the function 6 hex preset single register for 1 register (16 bits),
and the function 10 hex 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 and are stored as 4x registers (40001–4FFFF). The parameters are read using function 03 hex
read holding registers and written using function 10 hex preset multiple registers. Readable sizes range from 1 register (2 characters) up
to 10 registers (20 characters).
9.10 Examples
9.10.1 Overview of the Examples
The examples in the following chapters show various Modbus RTU commands.
9.10.2 Read Coil Status (01 hex)
Description
This function reads the ON/OFF status of discrete outputs (coils) in the drive. Broadcast is never supported for reads.
Query
The query telegram specifies the starting coil and quantity of coils to be read. Coil addresses start at 0, that is, coil 33 is addressed as 32.
Example of a request to read coils 33–48 (status word) from follower device 01.
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