Clock 1Hz - Problem

Hi,

I'm using an datalog (an example provided on the forum) and an CPU 1214DC/DC/DC. 

I also turned on the clock memory bytes option in the CPU to generate a 1Hz clock to do the writing. However, I executed the block for at least 1 hour and only 41 records were recorded during that time.

Why does the 1Hz clock is not working properly? Is it because I have the datalog in the Main?

Does someone have an example about how to generate a 1Hz clock?

Thanks and Regards

That should be easy enough to check.  Go online and watch the bit or use it to set an unused output and watch the flash.

Hi, 

Can you please post what did you implemented. Some screenshot or a PDF printout of this part of the code.

Just a note: In the SIMATIC S7-1200 Easy Book on page 73 you can read this: "Because clock memory runs asynchronously to the CPU cycle, the status of the clock memory can change several times during a long cycle."

Probably that is what happens. Please upload some info about the application, and some info about the cycle times/execution times of your code. 

I am looking forward to hearing from you!

Hi.

Doubtful that the issue is with the 1Hz (1sec) pulse.

As a test.. place a counting variable in code to count the 1Hz pulses and do the test again.

Some issue that comes up regularly is that the memory bit used for the frequency pulse also overlaps another memory location. Example MB100 is pulse generated bits and MW100 is also used by user program as memory storage.

w

Hi,

I put a Counter as suggested and I saw that it is not working properly. That is, to increase 1 it took several minutes.

I left the program running several hours and when I returned it only had recorded 62 records.

What can i do to fix this problem?

Thanks ind advance 

Thanks for the acknowledgement Jeff.

I think it is important to resolve the issue.
If it is overlapping memory then that can cause havoc/chaos later on.

Note to Siemens:
The S7-200 showed us when we were using overlapped memory..
please do this in TIA for all resources. Thank you!

To further your thoughts Jeff, I include x2 FAQ links for Bruno..

[LINK1]

[LINK2]

Hi ,

Thanks a lot for all the suggestions. I'm going to change the adress and try the function. If that doen't work I will make an clock just like in the examples you gave me. Thanks!!

Regards

William_B

Hi.

Doubtful that the issue is with the 1Hz (1sec) pulse.

As a test.. place a counting variable in code to count the 1Hz pulses and do the test again.

Some issue that comes up regularly is that the memory bit used for the frequency pulse also overlaps another memory location. Example MB100 is pulse generated bits and MW100 is also used by user program as memory storage.

w