BECKHOFF BK3000 - Manual (Page 52)

Appendix
52 BK3xxx/LC3100
DPV1 PROFIBUS
(BK3x10 / BK3500 / LC3100 only)
The DPV1 PROFIBUS specification includes a description of the acyclical
read/write services. The acyclical read/write services can be used to
transfer larger quantities of data than the maximum of 244 bytes of cyclical
output or input data.
A distinction is drawn between the master with which data is also cyclically
exchanged (the class 1 master) and other masters (class 2 masters).
The acyclical connection between the class 1 master and a slave is
automatically established at the same time as the cyclical connection
(parameterisation, configuration), provided the DPV1 services are activated
in the User_Prm_Data (byte 0, bit 7 = 1).
The acyclical connection between a class 2 master and a slave is
established by means of an initiate service. The connection is established
as soon as the initiate service has successfully been completed.
Once established, read or write services can be used to address various
data sets within the slave with the aid of a slot number and an index.
In the S7 the DPV1 services can be used with SFC58 (write) and SFC59
(read). Since the S7 master is a class 1 master, the DPV1 services must
additionally be activated in the User_Prm_Data (byte 0, bit 7).
In TwinCAT a "Protnumber" can be set on the bus coupler ADS tab to use
the DPV1 services with the transfer functions ADSRead and ADSWrite.
The possible values for the slot number and the index defined for the bus
coupler are listed below.