WAGO I/O-SYSTEM 750 Manual page 44

44 • I/O Modules
Special Modules
2.1.1.8.2 Mailbox Communication
Modules with mailbox functionality have an acyclic communication channel
(mailbox) in the process image. The data exchange between module and ap-
plication can be significantly expanded over this channel without enlarging the
process image. The mailbox masks cyclic data in the process image if active.
Depending on the module function, the remaining cyclic data is valid and
available during mailbox communication (see page 32, Figure 9).
All relevant functions and configuration steps for communication with other
Bluetooth
of the most important mailbox commands vital for the manual configuration of
the module through the process image. To configure the module using
WAGO-I/O-CHECK, however, this knowledge is not necessary; all module
functions are accessible via graphical interface.
Note
Please pay attention to the instructions for the use of modules with mailbox
functionality in the respective handbook for your coupler/controller.
2.1.1.8.2.1 Aging of Data by the Mailbox
If the mailbox is activated, it covers a part of the process data. Thus, select
data is covered in the input process image(see Figure 14). Data not covered is
not updated either if at least 1 byte of the respective slot of the mailbox is cov-
ered. After the mailbox is deactivated, the current data from the last received
process image is immediately displayed.
Without Mailbox
Received process image
Control/status byte
Byte internally used
®
devices are mapped by mailbox commands. This make knowledge
Cutoff size
Slot 1 Slot 2
Process images of the remote devices
Input process image
Slot is updated
Slot 3 Slot 4
WAGO-I/O-SYSTEM 750
I/O Modules