10/30/2010 1:38 PM | |
Joined: 7/28/2010 Last visit: 3/18/2024 Posts: 184 Rating: (11) |
Hi, The resolution and the accuracy of the system time are 1 ms for the S7-400 and CPU 318 and 10 ms for all other S7-300 CPUs. |
10/31/2010 12:13 PM | |
Joined: 7/28/2010 Last visit: 3/18/2024 Posts: 184 Rating: (11) |
Hi, The issue is not the OB1. OB35 has higher priority than OB1. CPU will execute OB35 whenever it happens and delays OB1. It seems that CPU receives the interrupt for OB35 while it is running OB35. The execution of OB35 is longer than 5ms. You can have only few instructions in your OB35 to make sure it is done before next interrupt butOB35 will happen constantly and that will increase your cycle time for running OB1. I really don't recommend going below the 10ms because this CPU is way slower than CPU318 or S7-400 and that is the reason that those can run timers down to 1ms. Stick to the CPU specificationor change the CPU if you reallyneed 1ms time interrupt. 1ms is really quick,what is your application that demands such a fast timer? Regards, Behnam www.sigmaprocess.ca |
10/31/2010 5:12 PM | |
Posts: 947 Rating: (45) |
you can use OB80 with sfc43. In OB35 you shold use minimum instruction. |
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