Storage Of Data; Ind (Index); Text Blocks; Conversion Factor - Danfoss VLT DriveMotor FCP 106 Programming Manual

RS-485 Installation and Set...
Reading 3-14 Preset Relative Reference (32bit): The holding
registers 3410 & 3411 holds the parameters value. A value
of 11300 (Decimal), means that the parameter is set to
1113.00.
3 3 For information on the parameters, size and converting
index, consult the product relevant programming guide.

3.9.2 Storage of Data

The coil 65 decimal determines whether data written to
the frequency converter are stored in EEPROM and RAM
(coil 65=1) or only in RAM (coil 65= 0).

3.9.3 IND (Index)

Some parameters in the frequency converter are array
parameters e.g. 3-10 Preset Reference. Since the Modbus
does not support arrays in the holding registers, the
frequency converter 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. See also .

3.9.4 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.

3.9.5 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.

3.9.6 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 03hex "Read Holding
Registers." Parameters are written using the function 6hex
"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).
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VLT DriveMotor FCP 106 and FCM 106 Programming Guide
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 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).

3.10 Examples

The following examples illustrate various Modbus RTU
commands.

3.10.1 Read Holding Registers (03 hex)

Description
This function reads the contents of holding registers in the
follower.
Query
The query message specifies the starting register and
quantity of registers to be read. Register addresses start at
zero, that is, registers 1-4 are addressed as 0-3.
Example: Read parameter 3-03 Maximum Reference, register
03030.
Field Name
Follower Address
Function
Starting Address HI
Starting Address LO
No. of Points HI
No. of Points LO
Error Check (CRC)
Table 3.17 Query
Response
The register data in the response message are packed as 2
bytes per register, with the binary contents right justified
within each byte. For each register, the first byte contains
the high-order bits and the second contains the low-order
bits.
Example: hex 000088B8=35.000=35 Hz.
Field Name
Follower Address
Function
Byte Count
Data HI (Register 3030)
Data LO (Register 3030)
Data HI (Register 3031)
Data LO (Register 3031)
Error Check (CRC)
Table 3.18 Response
MG03N102 - Rev. 2013-12-02
Example (hex)
01
03 (read holding registers)
0B (Register address 3029)
D5 (Register address 3029)
00
02 - (parameter 3-03 Maximum Reference
is 32 bits long, i.e. 2 registers)
-
Example (hex)
01
03
04
00
16
E3
60
-