Isochronous Mode; What Is Isochronous Mode - Siemens SIMATIC PROFINET Function Manual

Functions

5.7 Isochronous mode

5.7 Isochronous mode
5.7.1

What is isochronous mode?

Objectives of isochronous operation
Assuming public transport were to operate at maximum speed while reducing stop times at
the passenger terminals to absolute minimum, the last thing many potential passengers
would notice of the departing contraption are its red tail lights. The overall travel time is,
however, decided by the train, bus or underground-railway clock, because well adjusted
timing is essential to a good service. This also applies to distributed automation engineering.
Not only fast cycles but also the adaptation and synchronization of the individual cycles
result in optimum throughput.
Just-In-Time
Figure 5-65
The high speed and reliable reaction time of a system operating in isochronous mode is
based on the fact that all data are provided just-in-time. The constant bus cycle time
PROFINET IO cycle beats the time here.
182
System cycle
PROFINET with STEP 7 V14
Function Manual, 09/2016, A5E03444486-AG