Hello,

Did you change the Process Image?

Otherwise, you need to read PIW256 (for example move PIW256 to MW256)

Or change your addresses of your Card to IW100 for example. (Below 128)

Best regards,

Wizard

Hi,

The CPU reads every cycle the Process Image. And put it in a table, to be used in the program.

Go to properties of CPU151-8, -> Cycle

Here you will find the Size of Process Image Input and output. Those addresses are read every cycle.

But when your address is outside this Process Image, you will need to read it through PIW, it will go to your card and get the value of the address.

Perhaps this link might help:Where and when do you need peripheral addressing?

This is for S7-300/ S7-400 CPU's

Best regards,

Wizard