Rockwell Automation 1791DS-IBxxxx Guard I/O DeviceNet Safety Modules - Manual (Page 111)

Rockwell Automation Publication 1791DS-UM001J-EN-P - May 2013 111
Configure Modules in RSNetWorx for DeviceNet Software Chapter 6
If the reset is successful, you see this message.
Note that the configuration owner is now reset, so the 1791DS module can
connect to a new owner, that is, the SmartGuard controller.
When you browse the network, the 1791DS module appears like this.
The exclamation point means the SNN has not been set (as shown below). This
makes sense because the device has just been reset.