hi mr.Banti,

have a look online in the HW-configuration. There you normally get the information about what the individual modules are complaining about, if theres an error.

regards,

if profibus node fail for some time we can check the error in hardware, but the node fail for one second and then reset , how can identify the problem

hi mr.Banti,

CPU is calling a specific OB when error appears. Use the SFC51 in this OB for further diagnostic.

see this FAQ:

How is a DP slave's diagnostic data read out with SFC 51 "RDSYSST" (with an integrated DP interface on the CPU as the DP master)?

hope this helps,

regars,