Exception Based Scheduling – the most efficient way to plan your factory – Part 2

Posted by Chris Curtis on 25-Nov-2020 13:03:21

In Part 1 of this blog series, we started talking about the benefits provided when your scheduling solution is made up of a perfect blend of automation and exception-based alerts, including improved asset utilisation, greater visibility of inventory, and increased agility.

In this second part we will be exploring a little bit more around the types of exceptions that can be used within SAP Production Planning & Detailed Scheduling (PP/DS), and in what way these are beneficial compared to building the same restrictions into your automated solution.


Dynamic Alerts

There are a vast range of standard dynamic alerts available “out of the box” in PP/DS, and some commonly used examples are below:

  • Order-based Delays – e.g. my production/process order is too late to meet my demand
  • Order-based Earliness – e.g. my production/process order is being produced too early to meet my demand
  • Stock alerts – e.g. order produces excess stock
  • Shelf-life – e.g. the shelf life of my production/process order is exceeded before my demand
  • Resource Alerts – e.g. the capacities of my resource are exceeded at a point in time

 Advantages of these dynamic alerts include:

  • Visualisation – they can be configured to be highly visual within the detailed scheduling planning board – you can choose to highlight or “flash” orders which have alerts linked to them, or provide these within a list
  • Simulation – dynamic alerts can be used alongside provide effective “what if” simulation within the Detailed Scheduling Planning Board, i.e. changes to the schedule provide “real time” update of the alerts. This can be managed with or without merging into the live schedule.


An example of “flashing” alerts in the DS Planning Board

The two points above side-by-side are very powerful – any exceptions resulting from an automated schedule can be highlighted within the DS Planning Board. Rescheduling of orders results in these dynamic alerts being updated immediately, therefore if all alerts are addressed, no orders remain highlighted. This allows great insight for a scheduler as the action of addressing an alert may result in additional alerts elsewhere, e.g. reacting to a delay alert by bringing an order forward in time may mean that other orders need to be pushed back, triggering additional alerts.

Custom Alerts 

Every company is unique, and there may be scenarios where a decision is made to not build a specific restriction as a constraint within the automated schedule, but to instead use alerts to highlight to the scheduler that they need to make a decision. If the standard set of alerts cannot meet this, what can be done?

With a small amount of configuration and a little bit of development it is possible to produce custom alerts to meet specific business needs. Some specific examples could be:

  • The need for an extended cleaning activity every x number of days

Some FMCG companies require a deep clean every x number of days, but these could be handled as part of changeovers already planned within the schedule. An alert can be used here, instead of the scheduler inserting fixed changeover times, which reduces their available capacity, particularly when noting that setup and produce activities are stretched over changeover times (i.e. not running in parallel)

  • Minimum runtime of product group is not adhered to

The PP/DS Optimizer does a very good job of reducing setup times and costs, but when balancing with other objective functions, it might result in changing over to a specific product group for only a small amount of time, which is not cost effective. This information cannot be handled with rounding value at product level as across multiple products. A custom alert can be used to define where the total run time across multiple orders does not reach the minimum. This gives the scheduler extra opportunity to increase production for the product group which falls short, selectively for the product which makes the most sense

  • Prevent Changeovers at the same time

Some companies are constrained by certain tooling, labour constraints when performing changeovers between orders. Sometimes these can be handled by existing teams – e.g. running lines with reduced manning, but they need to be aware, and there needs to be a check that the workforce is available on shift to do so. It is possible to use secondary capacities to drive this, but this can impact on the complete schedule and is too restrictive. A custom alert can highlight were changeovers are scheduled across lines at the same time, to allow the scheduler to make an informed decision on their possible actions – e.g. extend order to delay changeover, speak to production teams about running line with reduced manning etc. This can be defined by changeovers over a specific duration etc


Alerts can be more beneficial than building certain “hard” constraints in the system, particularly where exceptions can be managed as an alternative. Schedulers can be empowered to use their soft knowledge, by being presented with the facts to allow them to make an informed decision. This is a desirable alternative to the system automatically building a schedule based upon a hard constraint, where making an alternative decision results in significant manual scheduling

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Chris Curtis-1Chris Curtis is the Scheduling & Execution practice lead and has been with Olivehorse for over 2 years. In total he has 14 years’ experience in designing and implementing planning and scheduling solutions, and prior to that he was a Production Scheduler in the Automotive industry.


Olivehorse can help you understanding your companies options and requirements with regards to your SAP APO PP/DS roadmap and scheduling challenges.

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