Extended Functions; 2-Byte Plc Interface; Word Alignment - Beckhoff BK3 0 Series Documentation

Extended functions

7 Extended functions
7.1

2-byte PLC Interface

Checking the CfgData can be deactivated if a DP master is not capable of operating with the modules listed
in the GSD file. In that case the master can send any CfgData, and as many inputs and outputs are
transferred as are described by the CfgData.
Deactivation of the CfgData checking can also be useful if a specific address range is to be reserved in the
PLC for future extensions. In that case, more input and output data is to be transferred than is in fact
necessary.
Deactivation of the CfgData check can be set in the UserPrmData [} 35]:
Byte Bit
1 0
In general, the I/O data from the modules (terminals or IE modules) is written by the coupler in the standard
sequence (first the complex, then the digital modules), as is also the case for other fieldbus couplers; this
has already been described in connection with the structure of the process image in the coupler. The
decision on a module-to-module basis as to whether the module is mapped in compact or complex form,
which would otherwise be possible under DP, is omitted when CfgData checking is deactivated. In that case,
the setting made in the UserPrmData applies to all modules:
The compact or complex mapping can be set in the UserPrmData [} 35]:
Byte Bit
9 2
The extended GSD file must be used to deactivate CfgData checking and to specify compact/complex
mapping textually in the master's configuration tool.
7.2

Word Alignment

In order to obtain the I/O data in the controller's process image in a clear form in controllers with word-
oriented process images, it is possible to specify that word alignment is used when the coupler generates its
process image. This involves a dummy byte being inserted for every variable that is larger than one byte and
which would start on an uneven address.
Word alignment can be set in the UserPrmData [} 35]:
Byte Bit Value
9 5 1
bin
When using the DP modules it is necessary to ensure that only those complex modules that are identified
with word alignment are used.
The extended GSD file must be used in order to set word alignment in text form in the master's configuration
tool and to be able to select the word alignment module.
72
Value Description
1 CfgData checking is deactivated
bin
Value Description
0 Analog modules are mapped in compact form (only with the input or
bin
output user data)
1 Analog modules are mapped in complex form (including control/status
bin
for register access and the same data length in the inputs and outputs)
Description
Word alignment is active
Version: 4.3.0 BK3xx0