Communication
6.3 Acyclic Communication
Control Units CU240S
Operating Instructions, 07/2008 - FW 3.2, A5E00766042B AD
143
Description of fields in parameter request and response
Table 6-23 Description of fields in parameter request
Field
Data type
Values
Note
Unsigned8
0x01 … 0xFF
Request
reference
Unique identification of the request/response pair for the master. The master
changes the request reference with each new request. The slave mirrors the
request reference in its response.
Unsigned8
0x01
0x02
Read request
Write request
Request ID
Specifies the type of request.
In the case of a write request, the changes are made in a volatile memory (RAM).
A save operation is needed in order to transfer the data to the non-volatile
memory (P0971).
Unsigned8
0x00 … 0xFF
Number
Drive object ID
Setting up of the drive object number with a drive unit with more than one drive
object. Different drive objects with separate parameter number ranges can be
accessed via the same connection.
Unsigned8
0x01 … 0x27
No. 1 … 39
Limited by telegram length
No. of
Parameters
Defines the number of adjoining areas for the parameter address and/or
parameter value for multi-parameter requests.
The number of parameters = 1 for single requests.
Unsigned8
0x10
0x20
0x30
Value
Description
Text (not implemented)
Attribute
Type of parameter element accessed.
Unsigned8
0x00
0x01 … 0x75
Special function
No. 1 … 117
Limited by telegram length
No. of Elements
Number of array elements accessed.
Unsigned16
0x0001 … 0xF
FFF
No. 1 … 65535
Parameter
number
Addresses the parameter to be accessed.
Unsigned16
0x0000 … 0xF
FFF
No. 0 … 65535
Subindex
Addresses the first array element of the parameter to be accessed.