my problem is that the Digital input driver block not detecting the input change well.

I opened the digital input and monitor it at the hardware card,but not all the changes detected by the block.the speed of the cjange isn't very high it can be detected by the eyes.

So help please

Hi Engea,

have you used the Process image partition (short Pip)? 

The process image is generally updated by calling the OB1 (default setting). When process image partitions are used, they are updated by calling the respective associated cyclic interrupt OB.
As a rule, we recommend the use of process image partitions for PCS 7. Otherwise, "non-constant time response" will occur as a result of the free cycle of OB 1. This means that the process values are not processed and updated reliably in a temporal context.

For more information to the topic "Process image partition" can be found in the manual PCS 7 Compendium Part A - Configuration Guidelines (V9.0) in section Process image partitions (PIP).

With regards
Heisenberg