The planning process mainly consists of scheduling lead times of operations. Setup, adjustment, and operation times, which are used to calculate the lead time, can be specified for employees and for machines. Use the Based on field to specify whether you want the scheduling to take place based on labor times or machine times.

The Based on field is available in the capacity groups and in the operation calculation of production files. The value set for the capacity group is used whenever the capacity group is included in an operation calculation of a production file. The field value can still be modified here.

In the Type field, specify whether to plan based on an infinite or a finite capacity.

This percentage indicates the extent to which the capacity group can be scheduled for the operation. For example, you may want to keep some of the hours of a capacity group available to be able to execute a rush order or to remedy any failures.

The percentage is calculated on the value in the Hours per day field on the capacity lines.

Tip: The Schedule to field also allows percentages exceeding 100%. You might want to use such a percentage for capacity groups of which the capacity can easily be expanded by hiring additional manpower (labor planning) or machines (machine planning).

The value of the Schedule to field is retrieved from the capacity group settings and cannot be changed in the operation calculation for the production file.

Fill in a daily capacity to restrict the available capacity specified for the capacity group (see Calculated capacity). When scheduling a capacity group with multiple employees or machines, you can use the To plan per day field to specify that not all capacity can or may be used for one operation. For example, if there are three machines with a capacity of 8 hours, enter "8 hours" in the To plan per day field. Instead of 24 hours (3*8 hours), only 8 hours per day will now be planned for the operation.

Based on the calculated capacity and the value of To plan per day, a number of 'working units' is automatically calculated in the background. These working units determine the number of hours planned, for example:

Calculated capacity	To plan per day	Working units	Hours per working unit
8	8	1	8
12	8	1	12
16	8	2	8
32	8	4	8
32	16	2	16

If you fill in '0', the To plan per day field will not be restricted.If you enter another number, it is important that the calculated capacity and the To plan per day value are in line with your working units.

Example

The way in which an 18-hour operation is scheduled depends on the way in which the available capacity is restricted by the value in the To plan per day field.

	Monday	Tuesday	Wednesday	Thursday	Friday
Available capacity	8	8	2	8	8
Scheduled per day if To plan per day = 0	8	8	2	-	-
Scheduled per day if To plan per day = 4	4	4	2	4	4
	Monday	Tuesday	Wednesday	Thursday	Friday
Available capacity	24	24	24	24	24
Scheduled per day if To plan per day = 0	18	-	-	-	-
Scheduled per day if To plan per day = 8	8	8	2	-	-

This check box can be selected only if you chose 'Finite capacity' in the Type field. If you opt for scheduling based on infinite capacity, operations are always scheduled contiguously.

Contiguous or non-contiguous scheduling

When scheduling operations based on finite capacity, you can specify how the available time must be filled:

• Non-contiguous scheduling: All available capacity can be utilized. Any windows available in the schedule are filled.
• Contiguous scheduling: The entire operation must be scheduled contiguously. This means that any intermediate days (after the start day) must be without any load, and that the remainder must fit on the last day. For the 'Contiguous scheduling' option, it is assumed that only one operation is being performed for a particular capacity group at a time. If you fill the To plan per day field with a value that applies to more than one machine, because some machines can work in parallel, this could result in an illogical planning when using the contiguous scheduling method. You are therefore not recommended to use this combination.

If the capacity group is included in a part or production calculation, your selection of contiguous or non-contiguous scheduling will be used in the calculation. The field value can still be modified here.

Minimum lead time

The minimum lead time enables you to specify the minimum number of days to be scheduled for an operation in the capacity group, regardless of the number of hours that will actually be required for the operation. If the capacity group is included in a part or production calculation, the minimum lead time will be used in the calculation. The field value can still be modified here.

Set the field to '0' if you do not want to use a minimum lead time.

The minimum lead time could be used, for example, by companies that issue a number of operations on Monday that need to be ready by Wednesday. The operations themselves could take very little time, but they all have a lead time of three days: they will not be ready before Wednesday. Another example is the drying time required after a product has been painted.

This check box is only relevant when you are scheduling based on infinite capacity.

Refer to the section Which lead time is used in the planning? for more information about how minimum lead times are used in Isah.

This check box can be filled in only if you chose 'Infinite capacity' in the Type field. To always use a fixed lead time when scheduling for a capacity group, enter the fixed lead time in the capacity group settings. This value is used in the production files when the capacity group is added to the operations form. The field value can still be modified here.

If a production file has a fixed lead time greater than 0, the planning process always uses the fixed lead time.

See also Which lead time is used in the planning?

The estimated lead time is calculated by dividing the plan time by the value of the To plan per day field.

This is the start date of the operations that can be used for forward scheduling.

This is the operations end date that can be used for backward scheduling.

Restrictions can be specified for the entire production file and for individual operations.

A limitation enables you to restrict the options for the start or end date of a production file or an operation. For instance, if you select 'Must start on' and specify a date, you can make sure that the production file or operation will start on that date.

You can choose from the following options:

Not applicable:	The start and end dates are not restricted.
Must start on:	Fixes the start date. The operation must start on the restriction date.
Do not start before:	The operation cannot start before the restriction date.
Do not start after:	The operation cannot start after the restriction date.
Must end on:	Fixes the end date. The operation must end on the restriction date.
Do not end before:	Specifies that an operation cannot end before the restriction date.
Do not end after:	The operation cannot end after the restriction date.

Enter the restriction date to the right of the Restriction field.

During the planning process, restrictions have highest priority. If, for instance, you are planning based on finite capacity, but specify a restriction resulting in an overload, the planning result will still comply with the limitation.

A special situation occurs if you specify restrictions that are contrary to the planning direction. Let us assume that you are forward planning a production file using the restriction 'Do not end after'. During the lead time planning process, the restrictions are evaluated and the planning is performed again, in the opposite direction, in order to adhere to the restriction. The Planning method field (Operations production calculation, Planning tab) shows how the operation has actually been planned.

The priority you specify here is of an informative nature and does not affect the planning. If you do want the priority of the file, the customer, or another feature to affect the planning, you need to add the priority at a location that does affect the planning. For more information, see the description of priorities.

For the calculation of the progress, the estimated time and the time already entered against the operation line are taken into account. If the Plan time field was changed manually, for example because the operation is taking longer than expected, the progress percentage reflects this.

The codes in this field show how the file has been scheduled.

Code	Meaning
>	Scheduled forward
<	Scheduled backward
*	Based on infinite capacity
=	Based on finite capacity
KP	Customer priority
VP	Sales order priority
VD	Sales line shipping date priority
VS	Sales line status priority
PD	Production file end date priority
PP	Production file priority
PS	Production file status priority
^	Sort ascending priority
V	Sort descending priority

This field shows the number of hours expected to be required to perform the operation. By default, this time is calculated on the basis of the operation time:

Plan time = PR -/- AC

Where required, another value can be entered for the plan time. If you are planning by labor time, only the planned labor time can be filled in. If you are planning by machine time, this will be the planned machine time.

When scheduling the operation line, the plan time is taken into account, except if:

• A fixed lead time has been entered.
• The minimum lead time is longer than the plan time.

For more information, refer to Which lead time is used in the planning?

The plan time will change if:

• The preliminary time is modified. The preliminary (PR)/actual (AC) costing figures will then be recalculated.
• The actual time changes as a result of hours being processed during the time registration process, or as a result of backflushing.
• You manually change the plan time. If the actual time then changes, the plan time will change as well. For instance, if the actual working time is two hours, those two hours will be deducted from the manually entered plan time. In the example below, the plan time of 6 hours is manually changed to 7 hours. The registered actual hours will subsequently be deducted from those 7 hours.

Example

PR	Actual	Plan time
8	0	8
8	2	6
8	2	7
8	3	4