Data Areas - WAGO I/O SYSTEM 750 750-833 Manual

3.10.1 Data Areas

Addressing the data areas, which can be written with MSAC1/2_Write or read
with MSAC1/2_Read, is done via an index and the module number
(Slot_Number) included in the configuration table. The modules begin at 0,
i.e. the data areas of the bus coupler (basic device unit) can be accessed via
slot number 0.
The range of indices is 0 to 254. The availability of individual data blocks
(indices) depends on the module. The user data length of a MSAC1/2_Read
and MSAC1/2_Write telegram cannot exceed 240 bytes. However, the actual
lengths of the individual data areas depend on the modules.
Warning
All indices related to the register contents of complex I/O modules are read-
only by default. Writing the register data when parameterizing the I/O
module, e.g. setting the baud rate of serial interfaces 750-650, 750-651 and
750-653, is only possible for modules with the item number extension 750-
???/003-000. In this case, the user specific registers R32 to R47 are activated
for password-protected write access. Write protection to registers R32 – R47
are disabled by writing word 0x1235 into register R31. Write protection is
restored by writing any other value into register R31.
Acyclic writing of process data from binary or analog output modules, for
example, requires access only via MSAC2 connection. When supporting a
MSAC1 connection, output information is overwritten by the cyclic DP data
exchange or the PFC runtime system.
Note that valid write requests to the register structure can be positively
acknowledged, even if the write protection has not been activated. In this
case, however, the data to be written will not be transferred to the complex
I/O module. The transfer only occurs if the write protection is reset.
WAGO-I/O-SYSTEM 750
Bus System
Programmable Field Bus Controller 750-833
Acyclic Communication According to DP/V1
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