The transmission time specifies how long it takes to send a data package from the user area (data block) of the sending station, to the user area (data block) of the receiving station.
The transmission time is measured in the sending station:
The ready signal (I/O signal, see figure „Function model“) indicates that the transferred data are entirely located in the user area (data block).
Sending and receiving of data occurs cyclically in OB1. There is precisely one call of the communication function per cycle.
The measurement is repeated 100 times per configuration (measuring setup). This is used for determining the average value (typical value) and the fluctuations (minimum value, maximum value).
The following function model explains the measuring method:
The following table describes the intervals Tx:
| Time | Tx ist die Zeit from / to | |
|---|---|---|
| T1 | from | triggering all send jobs |
| to | data available in the user area of the receiving station | |
| T2 | from | setting the DO in the receiving station via direct command (ready signal) |
| to | ready signal at terminal DO of the receiving station | |
| T3 | from | ready signal at terminal DI of the sending station |
| to | all ready signals mapped in process alarm | |
Note:
Using a direct command as well as the process alarm minimizes the systematic error caused by the
signal runtime of the ready signal. Otherwise, the cycle times would be added to the signal runtime.