ReductionRatio¶
This value can be set individually for each IO device and defines its ReductionRatio to the basic cycle time of the PROFINET communication. That means if the basic cycle time is 1 ms and the ReductionRatio is set to 32, the process data will be exchanged every 32 ms between the IO device and the Communication Module.
The ReductionRatio provides the user the possibility to adapt the network times of each slave individually and optimally to the system restrictions. With this it is possible to decrease the bus load for getting lower reaction times for more time critical data of other IO devices.
| PROFINET basic cycle time | ReductionRatio of IO device | Update time of the process data of an IO device |
|---|---|---|
| 1 ms | 1 | 1 ms |
| 1 ms | 2 | 2 ms |
| 1 ms | 4 | 4 ms |
Note
Allowed values for the ReductionRatio are 1, 2, 4, 8, 16, 32, 128, 256 and 512.
For configuration of the ReductionRatio, attention should be paid to:
- the basic bus cycle time should not be overloaded, i.e. that not more RT frames can be transferred than would fit in the fastest bus cycle time.
- a time reserve for non RT frames (NRT) should be hold out (typically about 30 % of the projected basic bus cycle time)