SAP ABAP Message Number CN - 851 (CN) is used by

• Class (1)
• Function Module (2)

#	Object Type	Object Name	Object Description	Package	Structure Package	Software Component
1	Function Module	CN_NW_DAUER_CHK	Check normal and minimum process duration (std. network and net. plan)	CN_NET_STD	APPL	SAP_APPL
2	Function Module	CO2O_ACT_SET_DURATION	sets the duration of an activity	COIF	APPL	SAP_APPL