CAN@net II/Generic, Version 1.5
Web Interface
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In the section communication network, the Ethernet and CAN network can be
specified. Select Intranet, Internet or modem connection for the Ethernet. If the
CAN@netII /Generic should forward CAN request and response messages e.g.
CANopen SDO messages, choose this option. For slow CAN baud rates
(<500kBit) the TCP overhead could be reduced and the CAN@net II/Generic
tries to put more CAN messages into one TCP packet.
In the next section, the data burst collection can be configured. The TCP
overhead is reduced when the CAN@net II/Generic groups CAN messages
which are sent in a burst. If data burst collection is enabled (value > 0ms), the
CAN@net II/Generic collects all CAN messages until a pause of the configured
value is reached. The CAN@net II/Generic sends the collected CAN messages
after this pause or if a TCP packet is full.
Example: If there are some CAN nodes in a network which respond to a status
request message within 20ms, you can set the data bust collection to 20ms. The
CAN@net II/Generic will retrigger the burst collection time of 20ms with every
received CAN message. 20ms after the last CAN response message the
CAN@net II/Generic will send a TCP packet with all CAN responses of the
nodes.
In the section “Data congestion buffering”, the internal data buffer behavior is
configured. Dependent on your demands, the CAN@net II/Generic can
overwrite old data or reject new data in the case of a congestion situation.
Additionally, the buffer size can be increased or reduced. The configuration
applies in both directions CAN
Ethernet and Ethernet
CAN.
Besides the default configuration (buffer size 2000 CAN messages), there are
two useful cases
•
Buffer overwrite with reduced buffer size (100 messages): after a
congestion situation, the latest data are sent. Example: If a sensor
periodically sends temperature data via CAN, the CAN@net II/Generic
will send the latest temperature data after a congestion situation and old
data is discarded.
•
Buffer reject with increased buffer size (4000 messages): a short
congestion is completely buffered. Example: If a PC sends a software
update for a CAN node, a short congestion situation will not lead to data
loss and a possible update fail at the CAN node.
