3.3.3. Cycle time without communication

Definition of "cycle time without communication":

"Cycle time without communication" is the cycle time that develops without communication between DP master and distributed stations (ET200, programming unit, operator panel). Thus, communication with the distributed stations takes place neither via the STEP 7 program nor via the operating system of the DP master.

Defining a "cycle time without communication":

To define the "cycle time without communication", a load program is downloaded to the S7 CPU.
This load program enables the user to simulate the case, which occurs in practical operation, that other control jobs are executed in the DP master simultaneously to the communication.

Selecting the "cycle time without communication":

For this measurement, the length of the load program has always been selected in such a way that there is a no-load cycle time ("cycle time without communication") of 10 ms or 50 ms.
This implies that the length of the load program varies per DP master to ensure that the desired no-load cycle time of 10 ms is set.

• The following is configured in HW Config: S7 CPU, HMI, no ET200 stations ((this is necessary to prevent operating system accesses to the ET200)
• All programs used in the measurement are loaded. In the I/O program, flags are used instead of inputs and outputs. Otherwise, "OB85 peripheral fault" would be indicated since no ET200 station is configured. This would falsify the adjustment.