How To Access Parameters; Parameter Handling; Storage Of Data; Ind - Danfoss VLT AutomationDrive FC 300 Design Manual

RS-485 Installation and Set...

10.12 How to Access Parameters

10.12.1 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 (10xparameter number) DECIMAL.

10.12.2 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).

10.12.3 IND

The array index is set in holding register 9 and used when
accessing array parameters.

10.12.4 Text Blocks

Parameters stored as text strings are accessed in the same
way as the other parameters. The maximum text block size
10 10
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
padded with spaces.

10.12.5 Conversion Factor

Since a parameter value can only be transferred as a whole
number, a conversion factor must be used to transfer
decimals. See chapter 10.8 Examples.

10.12.6 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 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 two
registers (32-bits). Readable sizes range from one register
(16 bits) up to ten registers (20 characters).
280
Design 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 03 HEX "Read Holding Registers" and written
using function 10 HEX "Preset Multiple Registers." Readable
sizes range from one register (two characters) up to ten
registers (20 characters).

10.13 FC Control Profile

10.13.1 Control Word According to FC
Bit
no.:
Figure 10.15 CW Master to Follower
Bit
00
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
Explanation of the control bits
Danfoss A/S © Rev. 2014-02-10 All rights reserved.
Profile
Master-follower
CTW
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
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
Speed ref.
MG34S222