I/O Terminal /
EXTENDED FUNCTIONS
47
7 EXTENDED
FUNCTIONS
This chapter covers 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 GSE 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:
Byte
Bit
Value
Description
3
3
1
bin
CfgData checking is deactivated
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:
Byte
Bit
Value
Description
0
bin
Analog modules are mapped in compact form (only
with the input or output user data)
3
3
1
bin
Analog modules are mapped in complex form
(including control/status for register access and the
same data length in the inputs and outputs)
The extended GSE 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.
