Parameter number (PNU)
Bits no. 0-10 are used to transfer parameter numbers.
The relevant parameter's function is defined in the pa-
rameter description in the section entitled
Program-
ming
.
Index
Index is
used together with the parameter number to read/
write-access parameters that have an index, e.g. pa-
rameter 615
Error code
. The index is made up of 2
bytes, one lowbyte and one highbyte, but only the low-
byte 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 pa-
rameter 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 sev-
eral 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 pa-
rameters 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 tele-
gram's second byte, known as LGE.
To be able to read a text via the PWE block the pa-
rameter 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.
Example - Write a parameter value:
Parameter 202
Output frequency high limit, f
MAX
to be
changed to 100 Hz. The value must be recalled after
a mains failure, so it is written in EEPROM.
PKE = E0CA Hex - Write for parameter 202
Output frequency high limit, f
MAX
IND = 0000 Hex
PWE
HIGH
= 0000 Hex
PWE
LOW
= 03E8 Hex - Data value 1000, cor-
responding to 100 Hz, see conversion.
114
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