Siemens SIMATIC S7-1500 System Manual page 155

Configuring
7.11 Configuring the clock system
PROFINET IO interface X150 clock system
Proceed as follows to set the clock system of PROFINET interface X150:
1. Select the PROFINET IO system in the network view of STEP 7.
2. Make the settings for the send clock, etc. under "PROFINET subnet" > "Domain
management" > "Sync domains".
In coupled isochronous mode with other clock systems, the clock system of the PROFINET
interface is always leading.
You can find additional information on configuring isochronous mode on PROFINET IO in
the Isochronous mode (https://support.industry.siemens.com/cs/ww/en/view/109755401)
function manual.
PROFIBUS interface X126 clock system
You must follow the rules below during configuration if you want to operate the PROFIBUS
DP interface in isochronous mode:
Table 7- 12
If ...
A SINAMICS Integrated is configured
The X142 technology I/Os are operated
in isochronous mode
The clock system of the PROFINET IO
interface is coupled with one of the two
clock systems.
Consistency checks ensure that the setting is correct.
Proceed as follows to set the clock system of the PROFIBUS interface:
1. Select the DP master system in the network view of STEP 7.
2. Make the settings for the DP cycle under "Constant bus cycle time".
Note
Isochronous coupling of the PROFIBUS interface with other clock systems is not possible.
If you want to expand the drive configuration limits with distributed drive systems, connect
those distributed drive systems over the PROFINET IO interface X150. Only the PROFINET
IO interface X150 can be connected isochronously alongside the MC Servo to the clock
system of SINAMICS Integrated and the X142 technology I/Os.
154
Rules for configuring isochronous mode for PROFIBUS DP interface
The configured cycle time of the PROFIBUS DP interface
must...
Be equal to or an integer multiple of the configured cycle
time of the SINAMICS Integrated (PROFIdrive Integrated)
Be equal to or an integer multiple of the configured cycle
time of the X142 technology I/Os
Be equal to or an integer multiple of the configured cycle
time of the PROFINET IO interface
System Manual, 11/2019, A5E46600094-AA
SIMATIC Drive Controller