Time synch issue, S7 315-2DP and CP-342-5

Hi all,

I've been lurking for some time now and have learned plenty. I hope to be able to share as much knowledge as I have gained from this site. I have an issue that I need help with. I apologize if this has already been discussed. I have done a search but couldn't find anything.

I am trying to synchronize the time from an S7 317F-2DP master to an S7 315-2DP slave via a CP 342-5 card (the CP card is in the 315 station). I have set up the 2nd DP channel in the 317F as a time synch. master at 1 min. intervals (the 1st DP channel is connected to a Profisafe network). I have set up the 315 as a time synch. slave under the "Diagnostics/Clock" tab (both "In the PLC" and "On MPI"). But so far nothing is working. I would have expected to find a "Pass on time-of-day frame to CPU" option in the HW config window for the CP card but there is no such option. Or do I need to use an SFC in my program to pass on these time frames?

Thanks in advance for any possible help.

I searched on Siemens support, but could only find a FAQ pertaining S7-400: http://support.automation.siemens.com/WW/view/en/56771670
Maybe it is useful for you, maybe not.

There is also an SFC48 for syncronising all slaves, but I dont see that it does anything that the regular sync interval does not.

If you cannot get the canned function to work, it shouldnt be so hard to make your own function.
Use SFC1 to read the clock on one CPU and SFC0 to set it on the other CPU.
To transfer the TD value from one CPU to the other, create a regular S7 connection between the 2 CPUs (with the CP342-5 as a regular DP master), and then use a GET in the 315-2DP.

Yes, I saw that too. It seems that the CP342-5 does not support time of day synchronization. I was going to make my own function as you suggested but now it seems we have to replace the 315 with a 317 anyways (for more routing resources). So I will remove the CP card and connect to the 2nd DP port on the 317 instead. Then I will be able to use the built-in function.

Thanks for your help.