Danfoss VLT AutomationDrive FC 301 Series Design Manual page 196

RS-485 Installation and Set...
12.7.10 Parameter Value (PWE)
The parameter value block consists of two words (four
bytes), and the value depends on the defined command
(AK). The master prompts for a parameter value when the
PWE block contains no value. To change a parameter value
(write), write the new value in the PWE block and send
from the master to the follower.
When a follower responds to a parameter request (read
command), the present parameter value in the PWE block
is transferred and returned to the master. If a parameter
contains not a numerical value, but several data options,
e.g., 0-01 Language where [0] is English, and [4] is Danish,
select the data value by entering the value in the PWE
block. See Example - Selecting a data value. Serial
communication is only capable of reading parameters
containing data type 9 (text string).
15-40 FC Type to 15-53 Power Card Serial Number contain
data type 9.
For example, read the unit size and AC line voltage range
in 15-40 FC Type. When a text string is transferred (read),
the length of the message is variable, and the texts are of
different lengths. The message length is defined in the
second byte of the message, LGE. When using text transfer
the index character indicates whether it is a read or a write
command.
To read a text via the PWE block, set the parameter
command (AK) to 'F' Hex. The index character high-byte
12 12
must be "4".
Some parameters contain text that can be written to via
the serial bus. To write a text via the PWE block, set the
parameter command (AK) to 'F' Hex. The index characters
high-byte must be "5".
Figure 12.11 Text via PWE Block
194
PKE IND PWE
high
Read text Fx xx 04 00
Write text Fx xx 05 00
Design Guide
12.7.11 Supported Data Types
Unsigned means that there is no operational sign in the
message.
Data types
3
4
5
6
7
9
10
13
33
35
Table 12.7 Supported Data Types
12.7.12 Conversion
The various attributes of each parameter are displayed in
factory setting. Parameter values are transferred as whole
numbers only. Conversion factors are therefore used to
transfer decimals.
4-12 Motor Speed Low Limit [Hz] has a conversion factor of
0.1. To preset the minimum frequency to 10 Hz, transfer
the value 100. A conversion factor of 0.1 means that the
value transferred is multiplied by 0.1. The value 100 is
therefore read as 10.0.
Examples:
0 s ⇒ conversion index 0
0.00 s ⇒ conversion index -2
0 ms ⇒ conversion index -3
0.00 ms ⇒ conversion index -5
PWE
low
Rev. 2014-04-04 All rights reserved.
Description
Integer 16
Integer 32
Unsigned 8
Unsigned 16
Unsigned 32
Text string
Byte string
Time difference
Reserved
Bit sequence
MG33BF22