Buffers
A buffer is in (logical of physical) inventory point for a item at a certain location.
Different types of buffers exist:
- Default:The default buffer uses an “producing” operation to replenish it with additional material.
- Infinite:An infinite buffer is unconstrained and has an infinite supply of the material.Propagation through a bill of material will be stopped at an infinite buffer.
Fields
Field |
Type |
Description |
|---|---|---|
name |
non-empty string |
Unique name of the buffer.
This is the key field and a required attribute.
You have to use the convention of using “item @ location”
as the buffer name.
|
item |
item |
Item being stored in the buffer.
This is a required field.
|
location |
location |
Location of the buffer.
This is a required field.
The working hours and holidays for the buffer are taken
from the ‘available’ calendar of the location.
|
description |
string |
Free format description. |
category |
string |
Free format category. |
subcategory |
string |
Free format subcategory.
If this field is set to ‘tool’, the field ‘tool’ will
automatically be set to true.
|
onhand |
double |
Inventory level at the start of the time horizon.
Default is 0.
|
minimum |
double |
Desired minimum inventory, aka safety stock.
Use this field if the safety stock doesn’t change over
time.
The solver treats this as a soft constraint, ie it tries
to meet this inventory level but will go below the
minimum level if required to meet the demand.
A problem is reported when the inventory drops below
this level.The safety stock target is expressed as a
quantity. If you want to define a safety stock target
as a time value (aka days of inventory), you can set a
post-operation timeon the producing operation of the
buffer.
|
minimum_calendar |
calendar |
Refers to a calendar storing the desired minimum inventory
level, aka safety stock.
Use this field when the minimum inventory level is varying
over time. Otherwise use the minimum field. If both fields
are specified, the minimum field is ignored.
|
maximum |
double |
Refers to a calendar storing the maximum inventory level.
This field is not used by the solver.
A problem is reported when the inventory level is higher
than this limit.
|
maximum_calendar |
calendar |
Refers to a calendar storing the maximum inventory level.
Use this field when the maximum inventory level is varying
over time. Otherwise use the maximum field. If both fields
are specified, the maximum field is ignored.
|
producing |
operation |
This operation will be instantiated by the solver to
replenish the buffer with additional material.
You can specify this operation explicitly.
Or, you can leave this field blank and let the system
automatically create an operation. The generated operation
is using the ItemSupplier and ItemDistribution models as
input.
In versions before 3.0 the only way was the explicit
construction of the operation to populate this field. From
version 3.0 onwards we recommend to use the auto-generated
operations, unless you have some very specific modeling
requirements.
From version 4.0 onwards, this field is deprecated. It is
left only for backwards compatibility. New implementations
and upgraded installs should use the easier modeling
constructs itemsupplier, itemdistribution and operation.
|
flows |
list of flow |
Defines material flows consuming from or producing into this buffer. |
flowplans |
list of flowplan |
This field is populated during an export with the plan results
for this buffer. It shows the complete inventory profile.
The field is export-only.
The description of the flowplan model is included in the
section on operationplan.
|
tool |
boolean |
A flag to mark buffers that are actually representing a tool.
Default is false.
The impact on the planning results is visible in the
pegging and criticality calculations.
|
level |
integer |
Indication of how upstream/downstream this entity is situated
in the supply chain.
Lower numbers indicate the entity is close to the end item,
while a high number will be shown for components nested deep
in a bill of material.
The field is export-only.
|
cluster |
integer |
The network of entities can be partitioned in completely
independent parts. This field gives the index for the
partition this entity belongs to.
The field is export-only.
|
hidden |
boolean |
Marks entities that are considered hidden and are normally not shown to the end user. |