The Dynamic Scheduling Engine (DSE) makes the best possible use of the dates given on work orders to calculate the optimal scheduling solution. What is optimal depends on setup and the schedule is continuously recalculated as work progresses.
The DSE always calculates the start date of the work order. Therefore, calculations are required to accommodate the latest finish dates, i.e., the duration of the work order must be subtracted before it is sent to the Mobile Workforce Management. In addition, a buffer time can be defined to manage the set-up time between work orders.
The scheduling is dependent upon the importance of the work orders and the urgency of the work. The importance is determined by a scheduling value called base value. The urgency is determined by the restricting dates which indicate when a work order should be performed.
From the restricting dates either one or two periods are calculated. These two periods are called the primary period, which is when the work order should be performed due to the restricting dates, and the secondary period which is when the restricting dates are not met.
An important part of the Scheduling process is the SLA (service level agreement) calculation. The SLA late start and SLA requested finish dates will receive calculated values if there is a valid service contract with service lines and SLAs defined for one or several work types.
The SLA dates together with the planned and required dates are the restricting dates used when calculating the periods.
To handle the different business requirements there are several ways of setting restricting dates used by the DSE:
The specific external dates can be of the following types:
Date Field / Scenario | Description |
Appointment to Start | An interval when the work order is required to start. This is set by entering the requested start and late start (i.e., latest start) dates. |
Appointment to Complete | An interval when the work order should have been started and finished. This is set by entering the requested start and requested finish dates. |
Requested Start | The date and time the work order is requested to be started. This is a constraining date, meaning it is the first date at which the work order can start. This could be according to an agreement with the customer, or that the object to be worked on is not available until this point in time. |
Late Start | The latest date and time by which the work order must start in order to meet the date/time indicated in Requested Finish. This can either be a calculated value or manually entered. |
Requested Finish | The date and time the work order is requested to be finished. This is a soft constraining date, for instance a wanted delivery date for a service from a customer. |
These dates are manually entered on the work order.
The generic external dates can be of the following types:
Date Field / Scenario | Description |
SLA Requested Start | The latest time the work order or service request can be started without missing its SLA (Service Level Agreement). This value is calculated from the response time for the SLA in the SLA ID field. This field is only applicable for work orders or service requests that have originated from a service contract. |
SLA Requested Finish | The date and time the work order or service request is requested to be finished in order to meet its SLA. This value is calculated from the resolution time for the SLA in the SLA ID field. This field is only applicable for work orders or service requests that have originated from a service contract. |
These dates are set automatically based on the SLAs on the service contract.
The internal dates can be of the following types:
Date Field / Scenario | Description |
Planned Start | The requested start date according to the internal planning. The planned start can also be used in combination with the SLA dates to set an requested start. This is set by entering the planned start date, but can also be set automatically if the work order is generated from a PM Action. |
Planned Finish | The requested finish date according to internal planning. This is set by entering the planned finish date, but can also be set automatically if the work order is generated from a PM Action. |
The following table illustrates the different scenarios described above:
Date Field / Scenario | Entry Date | Planned Start | Planned Finish | Requested Start | Late Start (Latest Start) | Requested Finish | SLA Requested Start | SLA Requested Finish |
Appointment to Start | X | X | ||||||
Appointment to Complete | X | X | ||||||
Requested Start | X | |||||||
Requested Start with SLA Dates | X | X | X | |||||
Late Start and Requested Finish | X | X | X | |||||
SLA with Entry Date | X | X | X | |||||
SLA with Planned Start | X | X | X | |||||
Planned Start and Planned Finish | X | X | ||||||
Planned Start | X | |||||||
No Dates | X |
When the primary period and the secondary period are calculated, the work order dates are considered in certain precedence. First, the work order is evaluated in order to verify whether it is an appointment. If it is an appointment, the primary period is calculated according to the scenario below for appointments. If it is not an appointment, the work order will be evaluated according to the requested start scenario and so on. This evaluation will continue until either a primary and/or both primary and secondary scheduling period can be calculated.
The default values which are defined in scheduling basic data will be used for these calculations. These can be defined per work type so that the work type on the work order determines the values to be used. To differentiate between the work types used in IFS/General Data for Maintenance, the default values per work type (in scheduling basic data) are referred to as activity type defaults. These default values can also be defined for SLAs and are only used in the scenarios where the durations are calculated based on the given SLA dates.
Following is a list of the activity type defaults:
The SLA default values used are:
- Appointment to Start - When the requested start and late start dates have been entered. In this scenario, the requested start date will become the start of the primary period and the late start date will become the finish of the primary period.
- Appointment to Complete - When the requested start and requested finish dates have been entered. In this scenario, the requested start date will become the start of the primary period, and the requested finish date minus the work order duration minus the buffer will become the finish of the primary period.
- If all three dates are given, i.e., requested start, late start and requested finish, a calculation is performed to determine the finish of the primary period. The finish of the primary period will become the earliest of the late start and requested finish dates minus the work order duration minus the buffer.
- Requested Start - When the requested start date is the only date which has been entered. In this scenario, the requested start date will become the start of the primary period. The end of the primary period, which is also the start of the secondary period, is the requested start plus the default primary duration which is defined in the scheduling basic data (activity type defaults). The finish of the secondary period will be the end of the primary period plus the default secondary duration defined in the scheduling basic data (activity type defaults).
- Requested Start with SLA dates - When the requested start has been entered together with the SLA dates. In this scenario, the earliest start date will become the start of the primary period. The finish of the primary period, which is also the start of the secondary period, is the earliest of the SLA requested start and SLA requested finish dates minus the work order duration minus the buffer. The end of the secondary period is calculated by finding the secondary scheduling type duration (firstly on the SLA ID or if not found on the SLA, retrieved from the activity type). This duration is then added to the start of the secondary period.
- Late Start and Requested Finish - When the late start date is entered together with the requested finish date, the start of the primary period is the registration date on the work order. The end of the primary period is the earliest of either the late start date or the requested finish date minus work order duration minus the buffer defined on the activity type. The start of the secondary period is the same as the end of the primary period. The finish of the secondary period will be the end of the primary period plus the default secondary duration defined in the scheduling basic data (activity type defaults).
- Late Start or Requested Finish - The start of the primary period is the registration date on the work order. The end of the primary period is either the late start date or the latest completion date minus the work order duration minus the buffer defined on the activity type. The start of the secondary period is the same as the end of the primary period. The finish of the secondary period will be the end of the primary period plus the default secondary duration defined in the scheduling basic data (activity type defaults).
When the work order has a valid service contract with service line and SLA, the SLA requested start and SLA requested finish dates on the work order will receive calculated values from the SLA.
If the requested start, late start or requested finish dates have not been entered, the SLA dates are sent to the Scheduling Engine. The start of the primary period is the planned start date or if empty, the registration date. The end of the primary period will be the earliest date of the SLA requested start and SLA requested finish minus the work order duration minus the buffer defined on the activity type. This date is also the start of the secondary period.
The end of the secondary period is calculated by finding the secondary scheduling type duration (firstly on the SLA ID or if not found, on the SLA retrieved fetched from the activity type. This duration is then added to the start of the secondary period.
The planned start and planned finish dates are internal planning dates. These dates are used when the requested start, late start or requested finish dates have not been entered, and in the case of the planned finish date, where the SLA dates have not been entered.
The start of the primary period is the planned start date or if it is not entered the registration date. The end of the primary period is the planned finish date minus the work order duration minus the buffer defined on the activity type. This is also the start of the secondary period.
If the planned finish date has not been entered, the end of the primary period is calculated by adding the primary scheduling type duration on the activity type to the planned start date. This is also the start of the secondary period. The end of the secondary period is calculated by adding the secondary scheduling type duration on the activity type to the end of the primary period.
If no dates are entered on the work order, the start of the primary period is the registration date on the work order. The end of the primary period is calculated by adding the primary scheduling type duration of the activity type to the registration date. This date is also the start of the secondary period. The end of the secondary period is calculated by adding the secondary scheduling type duration on the activity type to the end of the primary period.