Reading A Parameter Value; How To Access Parameters; Parameter Handling; Storage Of Data - Danfoss VLT AQUA Drive FC 200 Operating Instructions Manual

RS-485 Installation and Set...
NOTE
4-14 Motor Speed High Limit [Hz] is a single word, and the
parameter command for write in EEPROM is "E". 4-14 Motor
Speed High Limit [Hz] is 19E in hexadecimal.
The response from the slave to the master will be:
119E H 0000 H 0000
PWE
PKE

IND

7.4.2 Reading a Parameter Value

Read the value in 3-41 Ramp 1 Ramp Up Time
PKE = 1155 Hex - Read parameter value in 3-41 Ramp 1
Ramp Up Time
IND = 0000 Hex
PWEHIGH = 0000 Hex
PWELOW = 0000 Hex
1155 H 0000 H 0000
PKE IND
If the value in 3-41 Ramp 1 Ramp Up Time is 10 s, the
response from the slave to the master will be:
1155 H 0000 H 0000
PKE
IND
3E8 Hex corresponds to 1000 decimal. The conversion
index for 3-41 Ramp 1 Ramp Up Time is -2, i.e. 0.01.
3-41 Ramp 1 Ramp Up Time is of the type Unsigned 32.

7.5 How to Access Parameters

7.5.1 Parameter Handling

The PNU (Parameter Number) is translated from the
register address contained in the Modbus read or write
message. The parameter number is translated to Modbus
as (10 x parameter number) DECIMAL.

7.5.2 Storage of Data

The Coil 65 decimal determines whether data written to
the telegram are stored in EEPROM and RAM (coil 65 = 1)
or only in RAM (coil 65 = 0).
VLT AQUA Low Harmonic Drive Operating Instructions
H 03E8 H
PWE
low
high
H 0000 H
PWE PWE
high low
H 03E8 H
PWE PWE
high low
®
MG20T202 - VLT is a registered Danfoss trademark
7.5.3 IND
The array index is set in Holding Register 9 and used when
accessing array parameters.

7.5.4 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.

7.5.5 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.

7.5.6 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." 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 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).
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