10.6 Acyclic communication (Base Mode Parameter Access)
10.6.3 Parameter request/response data set
Structure of the P request/response data set This always consists of:
● Header (job identifier (request/change), job reference (job ID), number of parameters in the job, target axis / drive object ID)
● Parameter details (number of elements / indices, attribute, parameter number, subindex)
● Parameter values (only with job identifier "Change")
The data transmitted for a WRITE or READ request has the following structure.
Job parameters Byte n+1 Byte Offset
Header Request Header Request Refer‐
ence RequestID 0
Axis Number of param‐
eters 2
Job parameters Byte n+1 Byte Offset
Details 1. parameter Attribute Number of ele‐
ments 4
Parameter number 6
Subindex 8
...
nth parameter Attribute Number of elements Parameter number
Subindex Only write val‐
ues for parame‐
ter (change)
1. parameter value(s) Format Number of values
Values ....
...
nth parameter value(s) Format Number of values Values
...
Structure after Base Mode Parameter Access - Parameter Request
The following structure is defined for the subsequent Parameter Response. This is received after a request with _readRecord (request).
Parameter re‐
sponse Byte n+1 Byte Offset
Request Header Request Refer‐
ence mirrored RequestID mir‐
rored or error 0 Axis no./DO ID mir‐
rored Number of param‐
eters 2
Only read values for parameter (re‐
quest) /
Error values for negative response only
1. parameter val‐
ue(s) Format Number of values 4
Values or error codes 6
...
...
Only read values for parameter (re‐
quest) /
Error values for negative response only
nth parameter val‐
ue(s) Format Number of values
Values or error codes
The exact coding of the individual parts of the data structure can be obtained from the PROFIdrive profile or the SINAMICS S120 Function Manual. The assignment of "Request"
and the related answer "Response" for "Write data record" or "Read data record" using the
"Request Reference" job reference is important.
Request Reference
The "Request Reference" is used for the assignment of the write request to the following read request, and the response that follows thereafter, because the control can, in principle, process several actions (as many as 8) in parallel for different target devices using the same fieldbus.
Description of fields in parameter job and response
Field Data type Values Comments
Job reference Unsigned8 0x01 to 0xFF
Unique identification of the job/response pair for the master. The master changes the job reference with each new job. The slave mirrors the job reference in its response.
Job identifier Unsigned8 0x01
0x02 Read job
Write job Specifies the type of job.
In the case of a write job, the changes are made in a volatile memory (RAM). A save operation is needed in order to transfer the modified data to the non-volatile memory (p0971, p0977).
Response ID Unsigned8 0x01
0x020x81 0x82
Read job(+) Write job(+) Read job(-) Write job(-)
Mirrors the job identifier and specifies whether job execution was positive or negative.
Negative means:
Cannot execute part or all of job.
The error values are transferred instead of the values for each subresponse.
Drive object
number Unsigned8 0x01 to 0xFE Number
Setting for the drive object number on a drive unit with more than one drive object. Different drive objects with separate parameter number ranges can be accessed over the same DPV1 connection.
Number of parameters Unsigned8 0x01 to 0x27 No. 1 to 39
Limited by DPV1 telegram length Defines the number of adjoining areas for the parameter address and/or parameter value for multi-parameter jobs.
The number of parameters = 1 for single jobs.
Attribute Unsigned8 0x10
0x200x30
Value Description
Text (not implemented in the case of SINAMICS)
Type of parameter element accessed
Number of elements Unsigned8 0x00
0x01 ... 0xEA Special function No. 1 to 234
Limited by DPV1 telegram length
Field Data type Values Comments
Parameter number Unsigned16 0x0001 to 0xFFFF No. 1 to 65535
Addresses the parameter accessed
Subindex Unsigned16 0x0000 to 0xFFFE No. 0 to 65534
Addresses the first array element of the parameter to be accessed
Format Unsigned8 0x02
0x030x04 0x050x06 0x070x08
Data type Integer8 Data type Integer16 Data type Integer32 Data type Unsigned8 Data type Unsigned16 Data type Unsigned32 Data type FloatingPoint Other values: See PROFIdrive PROFILE v3.1 0x40 Zero (without values as a positive
subresponse of a write request) 0x410x42
0x430x44
ByteWord Double word Error
The format and number specify the adjoining space containing values in the telegram.
Data types in conformity with PROFIdrive Profile shall be preferred for write access. Bytes, words, and double words are also possible as a substitute.
Number of values Unsigned8 0x00 to 0xEA No. 0 to 234
Limited by DPV1 telegram length Specifies the number of subsequent values.
Error values Unsigned16
0x0000 to 0x00FF Meaning of error values --> see table 4-29 The error values in the event of a negative response.
If the values make up an odd number of bytes, a zero byte is appended. This ensures the integrity of the word structure of the telegram.
Values Unsigned16
0x0000 to 0x00FF The values of the parameter for read or write access.
If the values make up an odd number of bytes, a zero byte is appended. This ensures the integrity of the word structure of the telegram.
For more information on coding PROFIdrive data types, see PROFIdrive-specific data types (Page 351).
See also
Programming example (Page 387)
Reading and writing parameters with Base Mode Parameter Access (Page 356)