Eaton XN-312-GW-CAN, Manual

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8 Station variants
8.3 How the "station variants" operating mode works
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Gateway XN-312-GW-CAN 06/16 MN050003-DE www.eaton.eu
6. If this checksum matches one of the checksums on the PLC, this means
that the selected station variant on the gateway is permitted and can be
used.
7. If the checksums do not match, the actual configuration will be read
from the gateway. The actual configuration will then be compared with
the permitted station variants found in the list on the PLC.
8. If the PLC finds a matching station variant, it will load the corresponding
list onto the gateway. If it does not, the PLC will delete the list on the
gateway.
8.3.1 General principles / behavior of the gateway and the PLC
As soon as the config check is active, it will always be carried out regardless
of the station variant. Please note that the config check is used to check
whether the actual configuration matches the target configuration that has
been stored – the check for permitted station variants is carried out after-
wards.
What happens if the "station variants" operating mode is enabled?
• On the field bus side, the gateway will behave as though the full configu-
ration were physically connected. The address mapping used will be
based on the full configuration.
• Attempts to access variable values from missing nodes will return an
undefined value.
• Outputs written with the use of PDOs will not be set until the PLC has
confirmed the selected station variant by writing the checksum back to
the gateway.
When will the gateway exit "station variants" mode?
The gateway will exit the "station variants" operating mode and delete its lists
for the full configuration and for the selected station variants when one of the
following events occurs:
• A change to the actual configuration for the XN300 slice modules is
detected on the gateway.
• The gateway receives a start-remote-node command without the enable
signal for the "station variants" operating mode being activated before,
i.e., "Activation StationVariants Mode" = FALSE.
How does the enable process in which the PLC sends an enable signal
work?
The function block (FB) asks the gateway for the checksum. After receiving
this checksum, the FB checks whether one of the station variants stored on
the PLC has the same checksum as the station variant on the gateway (this
￫
Please note that if the config check is active and you want to put
a different station variant into operation, you will first need to
store the new station variant as a target configuration in the
device's memory
￫ "Switching the gateway on with a con fi g
check" section on page 38.