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Entry type: FAQ Entry ID: 44049612, Entry date: 08/13/2010
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How do you configure the SIMATIC S7-300 as time master or time slave for time-of-day synchronization via Industrial Ethernet in SIMATIC mode?

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Time-of-day synchronization is supported by all three major product families in the SIMATIC range: SIMATIC S7, SIMATIC S5 and PC. This synchronization can be done both via Industrial Ethernet and via PROFIBUS and MPI.

Time-of-day synchronization is supported by all three major product families in the SIMATIC range: SIMATIC S7, SIMATIC S5 and PC. This synchronization can be done both via Industrial Ethernet and via PROFIBUS and MPI. There are two modes available for time-of-day synchronization via Industrial Ethernet:

  • SIMATIC mode
  • NTP mode (see Entry ID: 17990844)

Time-of-day synchronization via Industrial Ethernet with the SIMATIC mode
This mode is usually used in process automation in conjunction with ISO transport services and is precise to +/- 10ms between the communications processor (CP) and the synchronized CPU with a resolution of +/- 1ms.
Since SIMATIC mode is based on SNAP services (i.e. ISO Layer 2 service) and works with MAC addresses, it can only be used with local Ethernet networks. This mode does not work with IP networks via IP routers, i.e. with configured IP subnets.

Important
CP 343-1 IT with article number 6GK7343-1GX20-0XE0:
When using the "Set CPU time", you must select the MPI address 2 for the CPU. This has been cleared with firmware update V1.1.


Fig. 01

Time-of-day synchronization for the S7-300 station is configured in the Hardware Configuration. In the Properties dialog of the CPU, you select the "Diagnostics/Clock" tab and then select the synchronization mode. You can configure the S7-300 CPUs as time master (time-of-day transmitter) or time slave (time-of-day receiver). Set whether synchronization is to be in the CPU (synchronization in the PLC) or via MPI (synchronization on MPI). Synchronization in the PLC includes the CPs. You can select a time interval of between 1 second and 24 hours for the synchronization.

Configuring time-of-day synchronization for the S7-300 CPU
There is only need to configure time-of-day synchronization for the S7-300 CPU if you are using one of the following Industrial Ethernet CPs:

  • CP 343-1 Standard with article number 6GK7343-1EX30-0XE0, firmware V2.2 onwards
  • CP 343-1 Advanced with article number 6GK7343-1GX30-0XE0, firmware V1.0 onwards
  • CP 343-1 Lean with article number 6GK7343-1CX10-0XE0, firmware V2.2 onwards

If you are using one of the above-mentioned Industrial Ethernet CPs, then you must make settings in the Properties dialog of the CPU. The settings depend on the configuration of the communication bus in the backplane bus of the CPU.

  • The communication bus is physically "wired through" to the MPI interface on the CPU. This setup is found in "small" CPUs, i.e. from the CPU 312 up to and including the CPU 315-2 DP and the C7 devices. In this case, in the Properties dialog of the CPU you select the "Diagnostics/Clock" tab and set "As slave" or "As master" for the synchronization mode on the MPI.


Fig. 02
 

Fig. 03

  • The communication bus is not physically "wired through" to the MPI interface on the CPU, i.e. the MPI interface and the communication bus are separate. This bus setup is found in "large" CPUs, i.e. from the CPU 315-2 PN/DP up to and including the CPU319-3 PN/DP. In this case, in the Properties dialog of the CPU you select the "Diagnostics/Clock" tab and set "As slave" or "As master" for the synchronization mode in the PLC.


Fig. 04
 

Fig. 05
 
Precise to +/- 10ms.

If the S7-300 is configured as time master, then the time-of-day messages of the CPU are forwarded via the Industrial Ethernet CP to the time slaves in the Industrial Ethernet subnetwork.

If the S7-300 is configured as time slave, then the time-of-day messages of the time master are forwarded via the Industrial Ethernet CP to the CPU.

You configure forwarding of time-of-day messages via the Industrial Ethernet CP in the Hardware Configuration of the S7-300 station. In the Hardware Configuration of the S7-300 station, you open the Properties dialog of the Industrial Ethernet CP and select the "Time-of-Day Synchronization" tab. Enable the "Forward time of day" function. Click "OK" to close the dialog.
 

Fig. 06
 
Note
More information on time-of-day synchronization via Industrial Ethernet

  • with the S7-400 is available in Entry ID: 18130164.
  • with the PC station is available in Entry ID: 44045424
  • with SIMATIC S5 is available in the manual "SINEC CP1430", section 6.6 "Setting and Reading the Time" in Entry ID: 12586144.
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