Beckhoff BK3 0 Series, Documentation

Page: 56 / 90

PROFIBUS DP communication
BK3xx0 56 Version: 4.3.0
Byte Bit Value Description
3 5 1
bin
Dummy output byte
activated
It is also necessary for the dummy output byte to be configured in the CfgData before the complex terminals:
CfgData DP modules
0x20 Dummy output byte
K-bus cycle counter
In order for the master to be able to check reliably whether precisely one (or two) K-bus cycles are always
being carried out during one DP cycle, a K-bus cycle counter can be transferred in the input data from the
Bus Coupler to the master. This is incremented after each K-bus cycle (0 is omitted, so that 1 follows after
255). The K-bus cycle counter must be activated in the UserPrmData and entered as a module in the
CfgData. The extended GSD file for the Bus Coupler is, however, necessary for this:
Byte Bit Value Description
3 3 1
bin
K-bus cycle counter
activated
It is also necessary for the K-bus cycle counter byte to be configured in the CfgData before the complex
terminals:
CfgData DP modules
0x10 K-bus cycle counter
5.2 DPV1 - acyclic data transfer
5.2.1 DPV1 Interface
By default, one MSAC_C1 connection and one MSAC_C2 connection with 52 bytes of data (4 bytes DPV1
header plus 48 bytes of user data) are supported. The MSAC_C1 connection is established along with cyclic
connection, and can be activated via the
UserPrmData [
}
35] :
Byte Bit Value: Description
0 7 1: MSAC_C1 connection is activated
The MSAC_C2 connection can be used either by the C1 master (which communicates with the slave
cyclically) or by a C2 master (which then only communicates with the slave acyclically), and has its own
establishment of connection. The parameters at the establishment of the MSAC_C2 connection
(Feature_Supported, Profile_Feature_Supported, Profile_Ident_Number, etc.) are not examined, and the
parameters of the request are mirrored in the response.
Slot_Number [
}
57] = 0 addresses PROFIBUS coupler data, Slot_Number [
}
57] > 0 addresses the data of
the function module(s).