Danfoss VLT PROFIBUS DP MCA 101 Programming Manual page 30

Parameter Access
PROFIBUS DP-V1 telegram for read/write from or to a
frequency converter parameter:
PROFIBUS Data unit
telegram
DP-V1
header
command/response
DU
0
Table 5.5 Structure of the PROFIdrive Parameter Channel
5 5
Table 5.6 shows the principle structure of the PROFIdrive
parameter channel.
The DP-V1 parameter request telegram consists of 3 data
blocks:
•
A request header, which defines the request (read
or write), and the number of parameters to
access. The master sets the request reference, and
uses this information to evaluate the response.
•
An address field where all addressing attributes of
the wanted parameters are defined.
•
A data field where all parameter data values is
placed.
DP-V1
Request
header
Address field Number of parameters
Data field
Table 5.6 Principle Structure of the PROFIdrive Parameter
Channel
28
PROFIdrive V3.0
parameter
channel
DU DU DU Req./Res. Data
1 2 3 Header
Parameter request Byte number
Request reference 0
Request ID 1
Axis 2
3
Attribute 4
Number of elements 5
Parameter number 6
7
Sub index 8
9
n'th parameter number 4+6*(n-1)
...
Data format 4+6*n
Number of values (4+6*n)+1
Values (4+6*n)+2
n'th data value ...
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VLT PROFIBUS DP MCA 101
The DP-V1 parameter response telegram consists of 2 data
blocks:
•
PROFIBUS
telegram
trailer
•
DP-V1
Response header
Parameter values
Table 5.7 DP-V1 Parameter Response Telegram
As the response telegram does not include parameter
addressing information, the master must identify the
structure of the response data from the request telegram.
5.2.9 Request/Response Attributes
Table 5.8 contains an overview of the possible attributes of
the PROFIdrive parameter channel.
Field
Request
reference
Request ID U8
A response header, which indicates:
- If the request is performed without
errors (response ID).
- The number of parameters.
-
The request reference set by the master
within the corresponding request.
A data field, where the requested data are placed.
If 1 or more internal requests have failed, a fault
code is placed instead of the data values.
Parameter response
Request reference mirrored
Response ID
Axis mirrored
Number of parameters
Format
Number of values
Values of error values
n'th parameter value
Data Values
1)
type
U8 0x01–0xFF –
0x01 Request
parameter value
0x02 Change
parameter value
0x42 Change
parameter non-
volatile
0x51 Request
parameter value
double word
0x52 Change
parameter value
double word
Byte
number
0
1
2
3
4
5
6
...
Remark
–
Identification
of read or
write request
MG37G202