What Is an Alternative Selection Mode in Scheduling?

Alternative selection mode is the run-level choice between letting the scheduling engine decide which machine runs a step and telling it yourself. In automatic mode the engine applies the configured selection strategy to every step that has alternate machines available. In manual mode you supply explicit machine choices for specific steps, and those choices override the strategy. The two mix rather than exclude each other: any step you did not make a choice for falls back to automatic.

The everyday version: automatic is handing the dispatcher the job and letting them find a machine. Manual is walking over and saying "this one runs on Mill-2 today." You can do both on the same job, and most planners do.

This entry belongs to the EDGEBIC by User Solutions glossary. For the wider vocabulary, see the manufacturing glossary, and for the layer beneath it, the definition of a selection strategy in scheduling.

How Alternative Selection Mode Works

A routing step can name more than one machine capable of doing the work: a true alternate that replaces the primary, or a member of a machine pool. Something has to decide which one actually runs it. The mode is that decision's owner.

Automatic

In automatic mode, every step with alternates is resolved by the engine using the configured selection strategy. Earliest completion picks whichever candidate finishes the job soonest given current queues. Primary first tries the designated machine and only spills over when it is genuinely full. Earliest start prefers whichever machine can begin soonest. The mode says "you choose"; the strategy says how.

This is the normal state, and for most shops it stays that way permanently.

Manual

In manual mode you supply a set of choices, each one naming a job, a step, and the machine it should run on. Those choices take precedence over the strategy, so the engine places the step where you said rather than where it would have picked.

Crucially, manual mode does not require you to choose for everything. A step you left without a selection is resolved automatically as usual. That fallback is what makes the mode practical: a real intervention is normally about one or two steps, not about every alternate in the plan.

The choices persist

The picks are not only used for the run in which you made them. They are also recorded as pending work center replacements, so a subsequent reschedule from the Gantt honors the same pin rather than re-shopping the step and moving it back. A planner who has decided where a job runs keeps that decision until they change it.

When to Use Which

The distinction worth drawing is between a decision and a policy.

A decision applies to this run. A rush order needs the fast press today. A machine is coming out for service tomorrow and you want the work off it now. A customer has asked for a specific cell. Manual mode is exactly right for these, and the fact that the choices stick through the next reschedule is what makes it useful rather than merely temporary.

A policy applies always. This customer's work goes on the new press. This pool should favor predictable routing over shortest lead time. Policies belong in configuration, either in the pool's selection strategy or in the primary designation, not in a set of manual picks you have to re-make every run. Using manual mode to enforce a standing rule means re-doing the same work indefinitely and eventually missing one.

A Concrete Example

A shop pools three mills. The pool's strategy is earliest completion, so on an ordinary run each job goes to whichever mill will finish it soonest.

On Monday a rush job arrives and the planner wants it on Mill-3, the newest and most reliable machine, regardless of what earliest completion would say. They set the run to manual mode, choose Mill-3 for the milling step of that job, and leave everything else alone.

The engine places the rush job's milling on Mill-3. Every other step on that job, and every step on every other job, is resolved automatically by earliest completion exactly as before. Nothing else in the plan changes shape.

On Wednesday the planner reschedules from the Gantt after a breakdown elsewhere. The rush job's milling stays on Mill-3, because the pin was recorded rather than being a one-run instruction. Once the job is finished, the pin has nothing left to hold and the pool returns to behaving as it always did.

Had the planner instead wanted every job for that customer permanently on Mill-3, the right move would have been to set the pool's strategy to primary first with Mill-3 as the primary, which achieves the same routing without any manual picks at all.

How EDGEBIC Uses Alternative Selection Mode

In EDGEBIC, the choice appears when you launch a scheduling run on jobs whose routings carry alternates. Choosing automatic and, optionally, a strategy lets the engine resolve everything. Choosing manual opens the selection surface where you pick machines for the steps you care about. Canceling that dialog aborts the run rather than falling back silently, so an interrupted choice never becomes an accidental plan.

The behavior to remember is the fallback: pick manual and leave a step unselected, and that step is resolved automatically. That is a feature, not a gap, and it is what lets a planner intervene surgically instead of exhaustively.

The neighboring definitions are the selection strategy that governs automatic mode, the true alternate work center that gives a step a choice in the first place, the work center group that pools interchangeable machines, and re-shopping which is what happens to an unpinned step on a later run. For the practical step, see how to add an alternate work center to a step and how to set a pool selection strategy.

Automation you can override is worth more than automation you cannot. That is the entire purpose of having a mode at all.