Hi all,

I am having a profibus communication problem. The machine system simply stops (it does not perform button and joystick commands) and I did not find a fault in the Simotion scout or in the CMS. I encountered this error (I/O access error when updating the process image input table P area, double-word access) in the diagnostic buffer in the module information. Could it be a hardware problem? Like a failure in connectors, cabling and lack of voltage on a slave? And if so, how do I locate the cause of the failure? I'm still learning about networks and communication protocols, as well as learning more about Step7, so thank you very much in advance for everyone's help.​

Hello AutoGen_3333661,

Does it mention a specific address in the diagnostic buffer?

Sometimes the process images of the CPUs come by default at the minimum. For example, in the CPU 414-3, by default the input/output process image is configured at 256 bytes and can be configured up to 8 kbytes. If you are trying to access an address higher than 256 and you have not increased the process image from the CPU Properties > Cycle, you will not be able to access that address.

It is not recommended to increase the process image to the maximum if you are not going to use so many addresses, since it can affect the cycle time.