Download the configuration into HW config. 
 
At this point, the bus error on the module should disappear.  
There could still be an active system error, particularly if an IO-Link is used. 
 
Possible causes: 
-  Line break (no IO-Link device connected) 
-  IO-Link device fault (e.g., external voltage supply not connected) 
-  Validation failed 
 
If the module still reports a bus error, 
there could be a problem in one of the following areas: 
 
-  Device relationship not established. 
Scan the network via "Target system" -> "Ethernet" -> "Ethernet user" -> "Search" 
and check whether the device is signaling under the correct device name and 
correct IP address. 
Adapt the Ethernet address or device name if necessary, assign the device name 
to the device once again and download the configuration. 
 
-  IO-Link is configured in the header module, the slot module is, however, missing or 
is connected at the wrong location. 
 
-  The IO-Link module is at the correct location, pin 4 was, however, not configured to 
IO-Link for the IO-Link port via the header module.