Features
Various settings for the cycle time can be made on the Features tab. The cycle time of the controller must always correspond to a power of two for RTCLass1, starting at 1 ms (1, 2, 4, 8...). If an incorrect base time has been selected, this is indicated by a corresponding message. For RTClass3 the 1 ms base time can be divided again and again by two (down to min. 31.25 µs). The device cycle time can be changed via the exponents. The minimum is always the Controller Cycle Time, unless a larger minimum cycle time than that of the controller is defined in the GSDML. The maximum for RTClass1 is 512 ms. The SendClockFactor is fixed here as a time base to the value 32 (31.25 μs * 32 = 1 ms). The Reduction Ratio also refers to this, i.e. a factor of 4 means a cycle time of 4 ms. The transmission point can be shifted again within a cycle via the phase; i.e. where RR = 4 the phase can be 1 - 4. However, this value is only of importance in the case of a synchronized transmission.
The PROFINET Watchdog Factor can also be adjusted here. Each device monitors the input of the cyclic data based on this factor. If the factor is set to the default value (3) this means that, with an RR of 4, three cycles require 12 ms. Hence, a device reacts after 12 ms to missing telegrams (e.g. with an alarm and/or disconnection of the AR). The limits and values are recalculated each time when adjusting the individual factors.