Use Of Isochronous Mode; Isochronous Applications - Siemens SIMATIC PROFINET Function Manual

Advantages of isochronous mode
The use of isochronous mode allows high-precision control.
● Optimized control
● Determinism
● Consistent (simultaneous) reading in of input data
● Consistent (simultaneous) output of output data
5.7.2

Use of isochronous mode

With the "Isochronous mode" system property, measured values and process data can be
acquired in a fixed system clock. The signal processing up to the switching-through to the
"output terminal" occurs within the same system clock. Isochronous mode thus contributes to
high-quality control and hence to greater manufacturing precision. With isochronous mode,
the possible fluctuations of process response times are drastically reduced. The time-
assured processing can be utilized to improve machine cycle times.
In principle, isochronous mode is worthwhile whenever measured values must be acquired
synchronously, movements must be coordinated, and process responses must be defined
and simultaneously executed, as in the following example. There are thus numerous areas in
which isochronous mode can be used.
5.7.3

Isochronous applications

Example: Isochronous measurement at several measuring points
Quality assurance requires precise measurement of dimensions within a camshaft
production process.
Figure 5-66
PROFINET with STEP 7 V14
Function Manual, 09/2016, A5E03444486-AG
Measuring of camshafts
Functions
5.7 Isochronous mode
183