Configuring Firming Time Fence in Planning Optimization

MB-330 By islever Editorial Last updated

Manage master plans

Short answer

A Change the firming time fence to one week because Planning Optimization bases auto-firming on the order start date, eliminating the need to add lead time as required by the legacy engine.

Question

A company uses the built-in Dynamics 365 Supply Chain Management master planning engine. Planned orders are automatically firming and are firmed during the current week.
You need to reconfigure the system for the new Planning Optimization master planning engine.
What should you change?
  1. firming time fence to one week Correct Answer
  2. firming time fence to lead-time plus one week
  3. open orders' firming date to be the requirement date
  4. firming time fence to be longer than the lead time
  5. firming time fence to 0

Key Takeaways

The main trap is applying the legacy formula (Lead Time + Period); Planning Optimization removes lead time from the equation because firming is driven by the order start date.

Learn why the firming time fence in Dynamics 365 Planning Optimization is set to one week instead of lead time plus one week, reflecting the shift from creation-date to start-date logic.

Common mistake: Choosing option B (lead-time plus one week) is the most common error, as candidates mistakenly carry over the legacy engine's calculation method which included lead time in the firming horizon.

Expert Analysis

The transition from the legacy master planning engine to Planning Optimization in Dynamics 365 Supply Chain Management fundamentally changes how planned orders are firmed. Under the legacy engine, the firming time fence was calculated as Lead Time + Firming Period. This meant that if you wanted orders for the current week to be firmed, you had to add the lead time to account for the manufacturing or procurement duration.

In contrast, Planning Optimization uses a date-based logic where the firming is triggered by the order start date (or requirement date), not the order creation date. As noted in community feedback, "Auto-firming is based on the order date (start date)." Because the system now looks directly at when the work must start rather than when it was created, the lead time is no longer added to the fence calculation. The comment explicitly states: "Because the order date (start date) triggers the firming, you don't have to consider the lead time as part of the firming time fence."

Therefore, to maintain the behavior of firming orders for the "current week" under Planning Optimization, the firming time fence should simply be set to one week. Options B and D incorrectly apply the legacy logic of adding lead time. Option C refers to open orders, which is distinct from planned order firming settings. Option E would disable firming entirely. The correct configuration is A.

Official Reference

https://learn.microsoft.com/en-us/dynamics365/supply-chain/master-planning/planning-optimization/planned-order-firming

This link opens the official vendor documentation in a new tab.

Exam Strategy

When migrating to Planning Optimization, always check if the setting has shifted from 'creation-based' to 'date/start-based'. If the trigger is the start date, remove lead time from your horizon calculations. Memorize that legacy formulas often become obsolete or simplified in the new engine.

Frequently Asked Questions

Why is lead time excluded from the firming time fence in Planning Optimization?

Planning Optimization determines firming based on the order start date (when work begins), not the order creation date. Since the start date already accounts for the necessary lead time, adding it again to the fence would result in double-counting.

How does Planned Order Firming differ between Legacy and Planning Optimization engines?

The legacy engine used a formula of Lead Time + Firming Period based on order creation. Planning Optimization uses a Date Basis approach where the firming time fence is applied directly to the order start date, simplifying the calculation.

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Discussion 4 contributions

Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.

From public community threads 4

  1. kikai 👍 3
    Correct. https://learn.microsoft.com/en-us/dynamics365/supply-chain/master-planning/planning-optimization/planned-order-firming
  2. globeearth 👍 1 Answered A
    Planning Optimization : => Date basis - Auto-firming is based on the order date (start date). => Lead time - Because the order date (start date) triggers the firming, you don't have to consider the lead time as part of the firming time fence. => Orders for the current week - To firm all orders that must start during the current week, the firming time fence must be one week.
  3. 982be89 👍 1 Answered B
    The company currently has planned orders firming during the current week. When moving to Planning Optimization, the firming logic is based differently, so to preserve equivalent behavior the time fence needs to account for the lead time + the desired firming period. So, Current firming horizon = 1 week Planning Optimization setting = Lead time + 1 week
  4. CCexamn 👍 1 Answered A
    Final answer: A. Firming time fence to one week This distinction is worth remembering: Old engine = Lead time + desired firming period Planning Optimization = desired firming period only.

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