Danfoss VLT 5072 - Page 106

VLT® 5000 Crane
Appendix
■ Read parameter description elements
With Read Parameter Description Elements it is possible
to read the characteristics of a parameter which could
be eg. Name, Default value, conversion,etc.
The table below shows the available parameter
description elements:
Index Description
1 Basic characteristics
2 No of elements (array types)
4 Unit of measure
6 Name
7 Lower limit
8 Upper limit
20 Default value
21 Additional characteristics
In the following example Read Parameter Description
Elements is chosen on parameter 001, Language,and
the requested element is index 1 Basic characteristics.
Basis characteristics (index 1):
The Basic characteristics command is split up
in two parts representing basic behaviour and
datatype. The Basic characteristics return a 16
bit value to the master in PWE
LOW
.
The basic behaviour indicates whether eg. text is
availableortheparameterisanarrayassinglebit
information in the high byte of PWE
LOW
.
The datatype part indicates if a parameter is signed
16, unsigned 32 in the low byte of PWE
LOW
.
PWE high basic behaviour:
Bit Description
15 Active parameter
14 Array
13 Parameter value can only be reset
12 Parameter value different from factory setting
11 Te x t ava i la ble
10 Additional text available
9 Read only
8 Upper and lower limit not relevant
0-7 Data type
Active parameter is only active when communicating
through Profibus.
Array means that the parameter is an array.
If bit 13 is true, the parameter can only be
reset, not written to.
If bit 12 is true, the parameter value is different
from the factory setting.
Bit 11 indicates that text is available.
Bit 10 indicates that additional text is available. Eg.
parameter 001, Language, contains text for index field
0, English, and for index field 1, German.
If bit 9 is true, the parameter value is read-only
and cannot be changed.
If bit 8 is true, upper and lower limits of the
parameter value are not relevant.
PWE
LOW
datatype
Dec. Datatype
3 Signed 16
4 Signed 32
5 Unsigned 8
6 Unsigned 16
7 Unsigned 32
9 Visible string
10 Byte string
13 Time difference
33 Reserved
35 Bit sequence
Example
In this example, the master reads the Basic
characteristics of parameter 001, Language.
The following telegram must be sent to the
frequency converter:
STX LGE ADR PKE IND PWE
HIGH
PWE
LOW
PCD1 PCD2 BCC
02 0E 01 40 01 00 01 00 00 00 00 XX XX XX XX XX
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