Rockwell Automation 1753-DNSI DeviceNet Safety Scanner for GuardPLC Controllers - Manual (Page 41)

Publication 1753-UM002A-EN-P - July 2005
Manage the Safety Network Number 4-5
SNN Mismatch RSNetWorx for DeviceNet compares the offline SNN to the online SNN
during each browse operation, one-shot or continuous, and during
upload and download operations. If the SNNs do not match,
RSNetWorx for DeviceNet indicates an error with the SNN. The
hardware graphic view displays the ! symbol over the safety device
icon. You can resolve the SNN error from the Safety Network Number
Mismatch dialog, as described on page 4-5.
When online, RSNetWorx for DeviceNet also checks for an SNN
mismatch whenever a safety device’s Device Properties dialog is
selected, either from the Device > Properties menu or by
double-clicking on the device. If an SNN mismatch condition exists,
the Safety Network Number Mismatch dialog is displayed as described
below.
Safety Network Number Mismatch Dialog
This dialog displays the online (device) SNN and the offline (software)
SNN. You can choose to upload the device’s SNN or download the
offline SNN to resolve the mismatch.
TIP
If the device’s SNN has not been initialized, the
Device Safety Network Number field displays the
default SNN: FFFF_FFFF_FFFF. When the device’s
SNN is FFFF_FFFF_FFFF, the Upload button is
disabled.