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Entry type: FAQ, Entry ID: 19866467, Entry date: 01/29/2010

How do you configure time synchronization?

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In an automation network of multiple SIMATIC stations you have the option of synchronizing the clocks of all the CPUs. For this, you parameterize the clock of one CPU as the "master clock" and set the interval at which synchronization is to take place. You parameterize the CPUs to be synchronized as "slave clocks". You set the parameters via the CPU properties.

Fig. 01: Setting synchronization on a CPU 315-2DP as example

You can set synchronization separately:

  • in the PLC (i.e. internal)
  • on an MPI (i.e. external)
  • on an MFI (i.e. external via 2nd interface)

Detailed information on time synchronization is available from the following sources:

  • For S7-300 CPUs - the manual "S7-300 CPU 31xC and CPU 31x, Technical Data", "Interfaces" chapter, in Entry ID:12996906
  • For S7-400 CPUs - the manual "Automation System S7-400 CPU Specifications", "Time Synchronization" chapter, in Entry ID:23904550
  • For CP 343-1 - the device manual "Part B CP 343-1", "Time Synchronization" chapter, in Entry ID:24485272
  • For CP 443-1 - the device manual "Part B CP 443-1", "Time Synchronization" chapter, in Entry ID:27013386


  • A description of time synchronization via Industrial Ethernet with the SIMATIC procedure is available in Entry ID:18130164.
  • A description of time synchronization via PROFIBUS in the SIMATIC environment is available in Entry ID:17544115.
  • A description of time synchronization via MPI subnetwork in the SIMATIC environment is available in Entry ID:17521938.

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