Chapter 3 Programming
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3.16.3 Ethernet speed
Since EtherCAT works in 100Mbps only, default setting of Ethernet speed is “Auto Negotiation”. Normally it
should work, but if not, set “100Mbps/Full Duplex” in “Ethernet port Link speed / Duplex mode” and set “Yes” in
“Change IP information” in [Configuration] tab in [Device] window. The PLC must be power-cycled to enable the
parameter change.
3.16.4 Cycle time of EtherCAT task
EtherCAT_Master task is automatically created when EtherCAT_Master object is added to the project.
Double click on “EtherCAT_Master” or right click and choose “Edit Object” to open configuration window.
Since MICRO-EHV+ series CPU handles all the tasks with a single microprocessor, the default value of “Interval”
(4000 s) must be changed to bigger. In addition, the cycle time EtherCAT task must be smaller than the cycle time
of MainTask and other tasks. If this value is too small to execute IEC program, 25 error (processor load watchdog)
will be detected. The minimum interval time depends on several different factors as follows.
CPU load rate (The size of user program for other tasks than EtherCAT task)
Variable declaration (It is recommended to declare variables in the mapping table in EtherCAT slave because
it is about two times faster than declaration in POU locally with referred from EtherCAT mapping table.
Total size of variables for EtherCAT slaves
Total number of EtherCAT slaves
If the exception of processor load watchdog (error code 25) is often found, perform [Reset origin] in [Online]
menu before downloading.
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