Danfoss VLT HVAC Drive FC 100 Series, Руководство по конструкции

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7.4.10 Parameter Value (PWE)
The parameter value block consists of 2 words (4 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 slave.
When a slave 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] corresponds to English, and
[4] corresponds to 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
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”.
PWE
high
PWE
low
Read text
Write text
130BA275.10
PKE IND
Fx xx 04 00
Fx xx 05 00
Figure 7.11
RS-485 Installation and Set...
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HVAC Drive Design Guide
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