16 Understand Time Fences and System Messages

This chapter contains these topics:

Section 16.1, "About Time Fences,"
Section 16.2, "About System Messages."

16.1 About Time Fences

Time fences are points in time in which you can make changes to either policy or operating procedures. JD Edwards World software includes three fences:

Freeze
Planning
Message Display

Figure 16-1 Time Fences

Description of "Figure 16-1 Time Fences"

Fence	Description
Freeze Fence (F)	A freeze fence holds, or freezes, the master schedule. In doing so, the system does not generate any planned orders from the current date to the number of days set in the field. This enables the master scheduler to review the schedule and make adjustments manually if required. The system allows the schedule to be "frozen." In addition, the system does not generate any messages that require action on existing work orders (such as an expedite message) within the frozen period of time. It displays warning action messages. JD Edwards World recommends that you set this fence at a point in time in which you need to freeze the MPS, depending on the nature of your product and the nature of the business environment.
Planning Fence (P)	A planning fence controls how the system uses the demand from forecast and customer orders in the ending available (EA) calculation. This fence also indicates where the method used to calculate ending available inventory changes from the demand rule in "Description 1" to "Description 2." For planning purposes, JD Edwards World recommends that you set the planning fence at a point from the current date that equals at least 1-1/2 times the cumulative lead time. This will depend upon the business environment and the nature of the product. Once inside the planning fence, you have committed resources to the product line.
Message Display Fence (D)	A message display fence suppresses action messages beyond the number of days that you selected from the current date. When you set this fence, calculations are not affected. JD Edwards World recommends that you set the message display fence at the point in which you do not need to act on action messages, depending on the cumulative lead time of the product and the business environment.

Fence

Description

Freeze Fence (F)

A freeze fence holds, or freezes, the master schedule. In doing so, the system does not generate any planned orders from the current date to the number of days set in the field. This enables the master scheduler to review the schedule and make adjustments manually if required. The system allows the schedule to be "frozen."

In addition, the system does not generate any messages that require action on existing work orders (such as an expedite message) within the frozen period of time. It displays warning action messages.

JD Edwards World recommends that you set this fence at a point in time in which you need to freeze the MPS, depending on the nature of your product and the nature of the business environment.

Planning Fence (P)

A planning fence controls how the system uses the demand from forecast and customer orders in the ending available (EA) calculation. This fence also indicates where the method used to calculate ending available inventory changes from the demand rule in "Description 1" to "Description 2."

For planning purposes, JD Edwards World recommends that you set the planning fence at a point from the current date that equals at least 1-1/2 times the cumulative lead time. This will depend upon the business environment and the nature of the product. Once inside the planning fence, you have committed resources to the product line.

Message Display Fence (D)

A message display fence suppresses action messages beyond the number of days that you selected from the current date. When you set this fence, calculations are not affected.

JD Edwards World recommends that you set the message display fence at the point in which you do not need to act on action messages, depending on the cumulative lead time of the product and the business environment.

16.1.1 What Are Time Fence Rules?

When you use a planning time fence rule that calculates an ending available that is based on the greater of forecast or customer demand, the forecast is "consumed." For rules C and G, this means that the forecast is reduced by the amount of the customer demand on that same time bucket. The system displays all adjusted and unadjusted values. In the previous table, this applies to rules C, G, and H.

JD Edwards World software uses the following planning time fence rules:

Rule	Description
Rule C	Description 1 Customer demand Description 2 Whichever is greater, forecast or customer demand
Rule F	Description 1 Forecast Description 2 Forecast plus customer demand
Rule G	Description 1 Whichever is greater, forecast or customer demand Description 2 Forecast
Rule H	Description 1 Whichever is greater, forecast or customer demand Note: When you use planning fence rule H, JD Edwards World recommends that you set the Planning Fence field on the Plant Manufacturing Data screen to the end of the planning horizon.
Rule S	Description 1 Customer Demand Description 2 Forecast
Rule 1	Description 1 Zero Description 2 Forecast
Rule 3	Description 1 Zero Description 2 Forecast plus customer demand

16.1.2 What Are the Time Series Calculations?

The Manufacturing and Distribution Planning systems provide four different time series calculations. These are:

Ending Available
Available to Promise
Cumulative Available to Promise
Forecast Consumption

Example: Ending Available Calculation

Ending Available (EA) is the amount of product available at the end of a time bucket after the system calculates the effect of all supplies and all demands for the time bucket.

The system uses the planning time fence rule and the following formula to calculate the ending available amount:

Add within the time bucket:
- Beginning Available (+BA)
For the first weekly time period, +BA = quantity on hand - safety stock

For remaining time periods, +BA = Ending Available from the previous time period (=EA)

Subtract according to the planning time fence rule:
- Forecast (-FC)
- Customer Demand (sales orders and interplant demand)

The remainder is the ending available (EA)

The following table shows how the system calculates the amount of product available at the end of a time period. Assume that the Lot Size = Lot for Lot, Planning Time Fence Rule = C.

Figure 16-2 Product Available at Period End

Description of "Figure 16-2 Product Available at Period End"

Available to Promise Calculation

Available to Promise (ATP) is the uncommitted portion of a company's inventory or planned acquisitions.

Available to Promise uses actual customer orders to identify inventory that might be promised to a customer. The planning time fence rule has no effect on ATP. Forecast is never included in ATP calculations.

The system uses the following formula to calculate the ATP quantity:

First period ATP = on-hand balance + work orders + purchase orders + planned orders - sales orders - work order parts list demand - interplant demand - unconsumed expired lot quantities.
After the first period, ATP = work orders + purchase orders + planned orders - sales orders - work order parts list demand - interplant demand - unconsumed expired lot quantities.

The system does not display negative ATP for following periods. However, the system reduces the Cumulative Available to Promise (CATP) by the negative amount.

Cumulative Available To Promise Calculation

Cumulative Available to Promise (CATP) is a running total of the ATP.

The system calculates CATP as follows:

First period CATP = ATP in first period - all negative ATP.
CATP in subsequent periods = sum of previous ATP + current period ATP - total negative ATP in future periods.

After the first period, CATP = sum of previous ATP + current period ATP - total negative ATP in future periods.

16.2 About System Messages

After you generate DRP/MPS output, the system creates action messages that:

Alert the master scheduler of possible adverse conditions
Display action recommendations that the master scheduler can process

The system displays messages by type. You can identify which items require attention based on the following message types:

Message Type	Description
A	Warning Message - User controlled
B	Order and Expedite
C	Cancel
D	Defer
E	Expedite
F	Frozen
G	Increase Order Quantity To
H	Decrease Rate Quantity To
I	Increase Rate Quantity To
L	Decrease Order Quantity To
M	Manual Reminder
N	Create Rate
O	Order
P	Firm Order
S	FPO Adjustment Suggestion
T	Past Due Order