时栅、时格设定完成之后如何应用？

aikimoo

其实不难理解。先弄清楚这个所谓的抵消主要用于考虑和计算ATP，另外时格的意义在于同一时格内，可视为同期的需求。

这样，跨时格的预测和订单的抵消就意味着，计算ATP时，需求（对能力、物料等）可以在不同时间内移动！这样是没有意义的。

icetea_cn

想说明的是，这种抵消不仅限于ATP，ATP更多的是一种试算性质的查询。而在这里，我的理解，forecast或者是sales order是要作为驱动生产的来源的。还是有本质的不同的。查了一下SAP的帮助，在PP/DS(Production Planning/Detailed Scheduling)模块中，讲到了以下内容。我认为是对我前面回复很多内容的佐证。

Forecast Consumption and Requirements Strategies

Forecast consumption is a central function in the SAP APO and SAP R/3 systems. It is an integral part of the SAP APO planning process.

In a very general sense, consumption is the comparison of two order types. One or more order types that represent actual requirements can then use up or consume another order type. More specifically in SAP APO planned independent requirements are consumed by other order types, such as sales orders, dependent demand, or transfer requests.

The purpose of consumption is to ensure that requirements are not duplicated in the system and that the most detailed requirements are used. Forecasts and sales orders are for instance both requirements. Since a forecast is less specific than a sales order, it is reduced when other more specific requirements, such as sales orders, exist for the same product. In this way if both forecasts and sales orders are used to generate receipt elements, for example planned orders, the correct quantity is always generated.

How the system consumes the forecast depends, of course, on the business strategy that you have decided on for planning. A make-to-stock situation has different needs as a make-to-order scenario, in which there are components with long lead times.

aikimoo

原帖由 icetea_cn 于 2008-8-27 01:24 发表
想说明的是，这种抵消不仅限于ATP，ATP更多的是一种试算性质的查询。而在这里，我的理解，forecast或者是sales order是要作为驱动生产的来源的。还是有本质的不同的。查了一下SAP的帮助，在PP/DS(Production Planning/Detailed Scheduling)模块中，讲到了以下内容。我认为是对我前面回复很多内容的佐证。

Forecast Consumption and Requirements Strategies

Forecast consumption is a central function in the SAP APO and SAP R/3 systems. It is an integral part of the SAP APO planning process.

In a very general sense, consumption is the comparison of two order types. One or more order types that represent actual requirements can then use up or consume another order type. More specifically in SAP APO planned independent requirements are consumed by other order types, such as sales orders, dependent demand, or transfer requests.

The purpose of consumption is to ensure that requirements are not duplicated in the system and that the most detailed requirements are used. Forecasts and sales orders are for instance both requirements. Since a forecast is less specific than a sales order, it is reduced when other more specific requirements, such as sales orders, exist for the same product. In this way if both forecasts and sales orders are used to generate receipt elements, for example planned orders, the correct quantity is always generated.

How the system consumes the forecast depends, of course, on the business strategy that you have decided on for planning. A make-to-stock situation has different needs as a make-to-order scenario, in which there are components with long lead times.

嘿嘿，抱歉。好像没看到关于具体的抵消策略的描述啊。如果你有SAP R3，可以自己看看系统里如何处理这个consumption的，不会是跨time bucket做的。

aikimoo

还有补充一下，forcast和order作为驱动生产的来源是没错，但都是通过计算ATP和PAB来的。所以我以为这个就是理解它的本质了，呵呵，个人看法。

icetea_cn

可能是我们的信息来源不一样，我一直在关注的是 sap的APO模块。不过我也只是看看help，具体的系统没有接触到。前面给出的内容是有关 Forecast Consumption的目的的。再看下面这个页面



Consumption in SAP APO
Purpose
This topic provides information about how consumption works in the SAP APO system.



Process Flow


       1.      The customer requirement consumes the planned independent requirement quantity that lies either directly before it or directly after it. You specify whether the system checks against planned independent requirements in the future or in the past by setting the Consumption Mode field on the Demand tab page of the location-specific product master.

       2.      If the planned independent requirement quantity that lies directly before the customer requirements does not cover the customer’s requirement, then the system looks for the next closest planned independent requirements either in the future or the past.

       3.      During this process, the system refers to the consumption periods maintained in the product master (see above). The consumption periods determine the intervals (for backward or forward consumption) within which customer requirements consume planned independent requirements. Customer requirements which lie outside the consumption period are not consumed.



If no consumption periods have been maintained, only those requirements are consumed that lie in the same planning period as the availability date of the customer requirements.

[ 本帖最后由 icetea_cn 于 2008-8-27 10:31 编辑 ]

aikimoo

原帖由 icetea_cn 于 2008-8-27 10:28 发表
可能是我们的信息来源不一样，我一直在关注的是 sap的APO模块。不过我也只是看看help，具体的系统没有接触到。前面给出的内容是有关 Forecast Consumption的目的的。再看下面这个页面



Consumption in SAP APO
Purpose
This topic provides information about how consumption works in the SAP APO system.



Process Flow
549587

       1.      The customer requirement consumes the planned independent requirement quantity that lies either directly before it or directly after it. You specify whether the system checks against planned independent requirements in the future or in the past by setting the Consumption Mode field on the Demand tab page of the location-specific product master.

       2.      If the planned independent requirement quantity that lies directly before the customer requirements does not cover the customer’s requirement, then the system looks for the next closest planned independent requirements either in the future or the past.

       3.      During this process, the system refers to the consumption periods maintained in the product master (see above). The consumption periods determine the intervals (for backward or forward consumption) within which customer requirements consume planned independent requirements. Customer requirements which lie outside the consumption period are not consumed.



If no consumption periods have been maintained, only those requirements are consumed that lie in the same planning period as the availability date of the customer requirements.

确实没接触过APO详细的东西。先谢谢icetea的资料。

我想这个是很明确的东东了，问题的关键在于consumption period的定义，在这个期间内才能进行需求的抵消，不知道帮助里有没有关于它的详细说法。个人理解，关键在于这个期间内对能力、物流等的需求可同质化，才谈的上抵消。这也是为什么在MPS的逻辑里，往往只是在当前time bucket抵消的原因。

追加一下的是，我相信无论如何，这个consumption period和time fence都是完全不搭界的两个东西。所以看到楼主的问题里那样的算法觉得很怪。

[ 本帖最后由 aikimoo 于 2008-8-27 11:01 编辑 ]

icetea_cn

哈哈，aikimoo，先握手。毕竟一个人接触的东西是有限的。我觉得能够在这里和大家分享，讨论，其实真的是一件很长功力的事情。
督促你去更深的思考很多东西。。

hb17908

时栅、时格确实是两个不同的概念
时格UF中更多的是在考虑能力和重复计划时考虑

感觉大家在讨论的时候，把有些东西说的太过复杂了。我看了半天，也是不好理解，还有，少搬点儿英文上来，呵呵
aikimoo在前面说过，在需求时栅中考虑order  需求时栅和计划时栅中考虑MAX(order,forcast) 计划时栅之外的就是forcast  其实这也是我最初理解的，不过，干嘛UF要搞那么多的消抵关系出来。。。。。

icetea_cn 前面举的15号用order 反向消抵，就保留此order和后面的20号的forcast，这个很好理解，但是如果是15号的order，用正向消抵呢？这种根据你的思路，和HELP中的说明好像还有出入？
15号的订单和前面1，10号的预测都是针对相同的需求，所以消抵前面，以15号的为准，这个没有错，但是为什么要设往后消抵呢？消抵就设一种，往后消抵不就得了？这里还是有问题，呵呵

aikimoo

原帖由 hb17908 于 2008-9-2 19:27 发表
时栅、时格确实是两个不同的概念
时格UF中更多的是在考虑能力和重复计划时考虑

感觉大家在讨论的时候，把有些东西说的太过复杂了。我看了半天，也是不好理解，还有，少搬点儿英文上来，呵呵
aikimoo在前面说过，在需求时栅中考虑order  需求时栅和计划时栅中考虑MAX(order,forcast) 计划时栅之外的就是forcast  其实这也是我最初理解的，不过，干嘛UF要搞那么多的消抵关系出来。。。。。

icetea_cn 前面举的15号用order 反向消抵，就保留此order和后面的20号的forcast，这个很好理解，但是如果是15号的order，用正向消抵呢？这种根据你的思路，和HELP中的说明好像还有出入？
15号的订单和前面1，10号的预测都是针对相同的需求，所以消抵前面，以15号的为准，这个没有错，但是为什么要设往后消抵呢？消抵就设一种，往后消抵不就得了？这里还是有问题，呵呵

相信UF的抵消关系是希望把我们说的那个逻辑细化，我质疑的是把时栅作为抵消的时段区隔，存在明显的不合理。另外，我确实也不太理解 前向 后向 等的业务逻辑。即什么条件下用什么样的抵消规则。也许icetea能有些建议？

hb17908

希望应用过相关消抵关系的朋友，继续来发言，共同澄清这里的概念