General Rules¶
The following chapter explains some rules on the usage of the libraries.
- A general rule is that ALL PLCOpen Function Blocks which are used for a specific drive are to be used in the same PLC-task. When multitasking is used for the PLC, it is allowed to have different drives in different tasks, but all Funciton Blocks belonging to a specific drive need to be in the same task. There is no multithreading protection for the AXIS_REF instance.
- The CMC_MotionKernel… and the COMC_Group… Function Blocks might be in a different task then the PLCopen Blocks (MC…). All Function Blocks belonging to the same fieldbus Communication Module have to be called from the same task.
- When AXIS_REF or AXES_GROUP_REF is used as input on a user defined FUNCTION_BLOCK or PROGRAM or FUNCTION, then ALLWAYS use it as VAR_IN_OUT and NEVER use it as VAR_INPUT or VAR_OUTPUT. The reason is that this would
- Break the consistency and destroy data
- Consume a lot of computing power by copying data.
- The “Min update time” update time for the fieldbus, defined under must not exceed the half of the scantime of the PLC-task. E.g. scantime of PLC-task is 5ms, then “Min update time” should not be greater than 2ms.
- The functionality of CompactMotion_AC500 library may be combined with the CoordinatedMotion_AC500 library. All single axis functions could still be used for an axis, even when it is combined with others to a group .