Lenze 931E/K Small Drives Control - Manual (Page 157)

Appendix
Communication interfaces
Control via CAN bus
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157 SW−HB 13.0002−EN 4.1
Processing of CAN messages
The 931E/K servo positioning controller uses a command interpreter for the CAN messages
received. The command interpreter is called every 1.6 msec. With every call, the command
interpreter can process one SDO or a special message such as a SYNC telegram or an
emergency message. Depending on their complexity, the processing of PDOs may even
take two time slices of the command interpreter. As a result, the processing speed for CAN
objects of the 931E/K servo positioning controller is subject to certain restrictions:
ƒ The control must not send PDOs more frequently than every 4 msec. Otherwise, they
might not be registered or evaluated by the 931E/K servo positioning controller. This
may lead to control jumps or motor jerks.
ƒ In the worst case, a PDO will only become effective in the controller after 4.8 msec
(e.g. as a speed setpoint). This may be the case, if two time slices are required for
PDO processing and the control sends the PDO directly after the preceding
command interpreter call.
ƒ There may be 8 msec between sending an SDO and a response from the controller
because the response data must be first compiled in the controller.
)
Note!
For more detailed information on the 931E/K servo positioning controller
communication and control via the CANopen interface and information about
the CAN bus wiring, please see the CANopen Manual for the 931E/K servo
positioning controller.