In process engineering, when transporting flammable bulk material, it must be ensured that the critical mass is not exceeded. This could happen due to conveyor system failures. To prevent this, two INSEVIS-S7 compact controllers are used that monitor each other. One PLC monitors the other (TÜV requirement) Various shutdown matrix: monitor the destination & source of the material flow of flammable bulk material, direct TCP communication with transmission in 12ms