PROFINET IO protocol
vacon • 33
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5
5.4.5.1
Parameter requests
There are two types of parameter requests in PROFIdrive:
•
Read requests for reading parameters from the device
•
Change requests for writing parameters to the device
Each parameter request consists of three elements:
•
Request header
•
Parameter address
•
Parameter value (only in Change requests)
Request header
Parameter
address(es)
Parameter value(s)
5.4.5.2
Request header
The request header consists of 4 fields, each one octet in size.
Table 31.
Octet
number
Field name
Description
Allowed values
1
Request Refer-
ence
Unique number for each
request/response pair. This
value is changed by the
master for each new
request. It is mirrored by the
slave in the response.
A bitmask with information about the
parameter characteristics.
2
Request ID
Defines the type of request.
Use 0x01 for Read requests.
Use 0x02 for Change requests.
Other values are not allowed.
3
Axis Number
Not used, should be set to 1. Use 1 for VACON
®
100 PROFINET IO.
Other values should not be used.
4
Requested num-
ber of
parameters
The number of parameters
affected by the request.
Values 1 to 39 are allowed.
The value 0 is not allowed.
Values 40 to 255 are not allowed.
Request header
8
High limit
Array of four
Unsigned8
Limit for valid values of the parameter.
9
Reserved
Array of two
Unsigned8
Reserved, always 0.
10
ID extension
Unsigned16
Not used, always 0.
11
Normalisation
reference parameter
Unsigned16
Parameter number, the value of which
is used as normalisation reference for
the parameter whose description this
is.
12
Normalisation field
Unsigned16
Contains information about normalisa-
tion of this parameter.
Sub-
index
Field name
Data type
Description