S
Stew Morris
Spot on Bob. Some of the threads above are overly prescriptive - even though we are talking standards. There's nothing wrong with varying approaches to coding. What's missing in most PLC programs that I've come across is careful design & above all structure. Let's face it, our plant engineer has to maintain a variety of systems, each doing a different job function. All the guy needs to do is to get in there quickly & find the route cause. If the programming language does not support encapsulation ( and maybe abstraction & reuse also ) may be he shouldn't be specifying it. Break it down into manageable chuncks !