True, it is a 'standard', but for whom? Users?? I think not. While it allows for vendors to write 'compliant' products, who says they ARE compliant? No one. PLCopen (for which I was the managing director for 7 years) has tried to develop testing for compliance but who really cares? Compliancy is ONLY good for and needed by a community that requires portability between code. If not then its no different than the good ol' days of Modicon vs Allen-Bradley. Regardless of the benefits (if any for the user base), being IEC-compliant doesnt mean a damn thing. The PLC programming environment you use is there because of the hardware you use. Do you CARE that it IEC-61131 compliant? Would you switch hardware vendors to get IEC-61131 compliant software? Rant over :) Flak jacket on - ready for input.