Storage Of Data; Ind (Index); Text Blocks; Conversion Factor - Danfoss VLT AutomationDrive FC 301 Design Manual

RS-485 Installation and Set...

12.12.2 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).

12.12.3 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.

12.12.4 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.

12.12.5 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.

12.12.6 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).
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).
®
VLT AutomationDrive FC 301/FC 302 Design Guide, 0.25-75 kW

12.13 Danfoss FC Control Profile

12.13.1 Control Word According to FC
Master-follower
Bit
no.:
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Illustration 12.16 Control Word
Bit
00
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
Table 12.20 Control Word Bits
Explanation of the Control Bits
Bits 00/01
Bits 00 and 01 are used to select between the 4 reference
values, which are pre-programmed in 3-10 Preset Reference
according to Table 12.21.
Programmed ref.
value
1
2
3
4
Table 12.21 Reference Values
MG33BF02 - Rev. 2013-12-20
Profile (8-10 Control Profile = FC
profile)
CTW Speed ref.
Bit value = 0 Bit value = 1
Reference value External selection lsb
Reference value External selection msb
DC brake Ramp
Coasting No coasting
Quick stop Ramp
Hold output frequency Use ramp
Ramp stop Start
No function Reset
No function Jog
Ramp 1 Ramp 2
Data invalid Data valid
No function Relay 01 active
No function Relay 02 active
Parameter set-up Selection lsb
Parameter set-up Selection msb
No function Reverse
Parameter Bit 01
3-10 Preset 0
Reference [0]
3-10 Preset 0
Reference [1]
3-10 Preset 1
Reference [2]
3-10 Preset 1
Reference [3]
12 12
Bit 00
0
1
0
1
187