Example of calculating the network cycle times of a multitasking application

Introduction

The configuration of the example is as follows:

Task periods:
- MAST: 60 ms
- FAST: 15 ms
The configuration comprises:
- 6 discrete TBXs configured in the MAST task and 4 discrete TBXs configured in the FAST task,
- 6 analog TBXs configured in the MAST task and 4 analog TBXs configured in the FAST task,
- 6 discrete Momentums configured in the MAST task and 4 discrete Momentums configured in the FAST task,
- 6 analog Momentums configured in the MAST task and 4 analog Momentums configured in the FAST task,

Convention

Depending on the configuration, the application of conventions involves:

Algorithm

The following table shows the algorithm:

Stage	Description
1	Calculation of R R = 60 / 15 = 4
2	Calculation of the equivalent number of devices NE_TBX_TOR = (R * 4 + 6) = 22 NE_TBX_ANA = (R * 4 + 6) = 22 NE_MOMENTUM_TOR = (R * 4 + 6) = 22 NE_MOMENTUM_ANA = (R * 4 + 6) = 22
3	Calculation of the network cycle times TCR_TMAST TCR_TMAST = 1.45 + ((0.5 * 22) + (0.9 * 22) + (0.4 * 22) + (0.6 * 22)) TCR_TMAST = 54.25 ms
4	Calculation of the network cycle times TCR_TFAST TCR_TFAST = 54.25 / 4 TCR_TFAST = 13.56 ms

Conclusions

The network cycle times of each equal:

The time period for MAST and FAST tasks are sufficient to refresh the inputs/outputs.