VLT
®
FCD Series
Parameter number (PNU)
Bits no. 0-10 are used to transfer parameter
numbers. The relevant parameter
’
s function
is defined in the parameter description in the
section entitled
Programming
.
Index
Index is used together with the parameter number
to read/write-access parameters that have an index,
e.g. parameter 615
Error code
. The index is made
up of 2 bytes, one lowbyte and one highbyte, but
only the lowbyte is used as an index.
Example - Index:
The first error code (index [1]) in parameter
615
Error code
must be read.
PKE = 1267 Hex (read parameter 615
Error code
.)
IND = 0001 Hex - Index no. 1.
The frequency converter will respond in the
parameter value block (PWE) with a fault code
value from 1 - 99. See
Summary of Warnings
and Alarms
to identify the fault code.
Parameter value (PWE)
The parameter value block consists of 2 words
(4 bytes), and the value depends on the defined
command (AK). If the master prompts for a parameter
value, the PWE block does not contain a value.
If you wish the master to change a parameter
value (write), the new value is written in the PWE
block and sent to the slave.
If the 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. parameter 001
Language
where [0] corresponds to
English
,
and [3] corresponds to
Danish
, the data value is
selected by entering the value in the PWE block.
See
Example - Selecting a data value
.
Via serial communication it is only possible to read
parameters that have data type 9 (text string).
Parameter 621 - 635
Nameplate data
is data type 9.
For example, in parameter 621
Unit type
it is possible
to read the unit size and mains voltage range.
When a text string is transferred (read) the length
of the telegram is variable, as the texts are of
different lengths. The telegram length is defined in
the telegram
’
s second byte, known as LGE.
To be able to read a text via the PWE block the
parameter command (AK) must be set to
’
F
’
Hex.
The index character is used to indicate whether
it is a read or write command.
In a read command the index must have
the following format:
Some frequency converters have parameters to
which a text may be written. To be able to write
a text via the PWE block the parameter command
(AK) must be set to
’
F
’
Hex.
For a write command the text must have
the following format:
Data types supported by frequency transformer:
Data types
Description
3
Integer 16
4
Integer 32
5
Unsigned 8
6
Unsigned 16
7
Unsigned 32
9
Text string
Unsigned means that there is no operational
sign in the telegram.
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