Festo CPX Series Electronic Manual page 102

4. Diagnosis and error treatment
Module diagnostic data: Module fault number
Function no. 2008 + m * 4 + 1
Description Fault number
Bit Bit 0 ... 7 fault number
Values 0 ... 255
Note Fault messages of the CPX−CP interface, see section 4.2
Tab. 4/10: Module fault number
4−18
m = module number (0 ... 47)
(fault number)
Festo P.BE−CPX−CP−E N en 0405NH