Mike

You may well be right that the designations only apply within O&G (and further that they may only apply within my corner of it!)

as for the distinction between planner and scheduler we have our angle on that as well. In European O&G the work is "prepared" or (to use the local flemish terminology) "preperated" by what are called here "preperators" (I never heard the word before moving to Belgium and have never gone to the lengths of getting a dictionary out to confirm my suspicion that it's not really a word).

The Preperator will prepare the work package  (one valve, one ISO of pipe, one piece of equipment) from the bolts up, including field check, scaffold requests, materials lists and a small activity plan including a calculation of the hours required to perform the job. Here that calculation is based on a set of standard norms, probably derived from some US Gulf coast standard

The scheduler takes these (there maybe anything from 100 to 3,000 of these in a block, more commonly with us  around 1,000) and ties them together into an overall schedule, applying system, resource, weather constraints and analysing risk with the team.

So, what you say can be true (the preperator knows how to build the job, the scheduler can use the software) but this is a pretty pessimistic outlook and acceptance of a scheduler as a software jockey will not likely generate a good schedule, unless you have very strong preperators. The most practical schedulers (in my experience) start as preperators, and often before that as fitters. The best at managment communication come from Project management / coordination. The worst have only ever run software. Our team is a mix of the first 2, thankfully.

So, what's a planner then? well, for me the "planning" is the culmination of the complete effort, major deliverables including the schedule, the workpacks, the delivered materials and mobilised contractors amongst several others that I'm sure I've forgotten, ready to hand over to the execution teams (which, OK includes a lot of the same people and functions). So here we tend to use Planner as an umbrella term for anyone that works in the planning phases of Business, Strategy and Preperation (Operators and Inspectors would probably exempt themselves from such a description!) and then support during pre-execution and execution phases

I have also heard of what we call preperators being referred to as planners, destinct from schedulers, materials procurers etc, but then you need a different umbrella term I guess