278 Fieldbus Communication
WAGO-I/O-SYSTEM 750
750-882 Media Redundancy ETHERNET Controller
Manual
1.5.0
Instance 198 (C6
hex
) “Input Only”
This instance is used to establish a connection when no outputs are to be
addressed or when inputs, which are already being used in an exclusive owner
connection, are to be interrogated. The data length of this instance is always
zero.
This instance can only be used in the “consumed path” (seen from the slave
device).
Instance 199 (C7
hex
) “Listen only”
This instance is used to establish a connection based on an existing exclusive
owner connection. The new connection also has the same transmission
parameters as the exclusive owner connection. When the exclusive owner
connection is cleared, this connection, too, is automatically cleared. The data
length of this instance is always zero.
This instance can only be used in the “consumed path” (from the point of view of
the slave device).
Common Service
Table 212: Static assembly instances – Common service
Service code Service
available
Service name
Description
Class Instance
0E
hex
Yes
Yes
Get_Attribute_Single Supplies contents of the appropriate attribute
10
hex
No
Yes
Set_Attribute_Single Modifies an attribute value
The software inspects the writing of attribute 3 of assembly instances 101, 102
and 103. If the limit value has been exceeded, it is identified and, if necessary,
corrected. However, a write request is not rejected. This means that if less data is
received than expected, only this data is written. If more data is received than
expected, the received data at the upper limit is deleted. In the case of explicit
messages, however, a defined CIP is generated even though the data has been
written.
12.3.5.7 Connection (05
hex
)
Because the connections are established and terminated via the connection
manager, the class and instance attributes of this class are not visible.
