Excellent posts gentlemen. I can see that you know exactly what you want 
to accomplish with each of your approaches. 

The example that I was referring to in my "70's era" planning used a 
slightly different approach since ours was an assemble to order and 
engineer to order capital products business with an average of 
approximately 12,000 parts in each finished unit. We had 6 major product 
lines that each had approximately 12 different models. Or 80,000+ item 
master was a challenge to balance what inventory could be stocked, and 
what must be purchased or manufactured to order. We spent a tremendous 
amount of time creating single level, modularized bills-of-material that 
we then used to construct master level planning items at the features and 
options level. In BPCS, these would be item type 5, created in BOM600. 
This is what we "master scheduled" and forecasted. By using this approach 
my product line (total item master =15,000 parts) was covered to a 98% 
level with 250 feature and option B/M's. By forecasting these 250 items 
well, we provided the maximum flexibility for sales of 2500-3000 end 
product configurations. This resulted (in 1980) in reducing lead time from 
15 to 20 weeks (depending on configuration) to 4 weeks, and maintained a 
consistent 95%, or better, on-time delivery, shipping $2.5 million/month 
with a $3 million inventory (about 10 turns/yr. Not bad in 1980). My whole 
point is that there is no "one size fits all" approach to MPS. Your 
organization strategy, culture, and position in your markets will dictate 
what type of planning approach you need to develop. You must also 
re-evaluate whatever approach you choose, periodically to make sure it is 
still viable. Rock on, gentlemen. 

Frederick C. Davy, CPIM, PMP
Business Systems Analyst
Interface Solution, Inc.
Phone: (315) 592-8101
Fax: (315) 592-8481
e-mail: fcdavy@xxxxxxxxxxxx

"lmittman" <lmittman@xxxxxxxxxxxxx> 
Sent by: bpcs-l-bounces+fcdavy=sealinfo.com@xxxxxxxxxxxx
10/20/2006 01:48 PM
Please respond to
SSA's BPCS ERP System <bpcs-l@xxxxxxxxxxxx>

"SSA's BPCS ERP System" <bpcs-l@xxxxxxxxxxxx>

Re: [BPCS-L] Resell Purchased / Master Schedule ?

The logic of MPS and MRP within BPCS are quite similar.  And, one can 
certainly set all Items to be MPS.  I have two (2) client who do this in 
order that only MPS Generation (MRP500) needs to be run.  However, adding 
to what Daniel and Roy have observed in their posts, there is one other 
critical difference between what MPS and MRP do in BPCS.

In the MPS Generation (MRP500), the Item's MPS Horizon Days is taken into 
consideration when Planned Orders are created.  That is, the concept of 
MPS Horizon is that our goal is to try and establish a fixed or controlled 
Master Production Schedule.  Therefore, when MPS generates, it is not 
permitted to create a Planned Order within the Item's Horizon Days because 
that time period is controlled by the Planner.  Thus, it creates the 
Planned Order on the first day after the Horizon Date, but with an 
Expedite Message.  This message alerts the Planner to the fact that there 
is an earlier requirement.  The job of the Planner is to determine if this 
new Planned Order can indeed be slotted within the Horizon and if so, it 
can be maintained in MRP Maintenance (MRP510) to place its Due Date 
earlier.  However, the Planner must also change it from a Planned Order to 
a Firm Planned Order so that it will remain on this earlier Date.

The MRP Explosion (MRP600) does not consider the Horizon Days and will 
create a Planned Order on whatever Date is required.

This distinction is critical in deciding how best to manage your overall 
planning for Production and for Procurement.  Specifically, if the Horizon 
is used and Planned Orders are created after the Horizon Date with 
Expedite Messages, then the corresponding Component Requirements will also 
be scheduled further out.  Then, when the Planned Order is moved earlier, 
those corresponding Component Requirements will also advance.  To properly 
coordinate the manufacturing and procurement functions, these departments 
must be coordinated in terms of the timing of when they perform their 

For example, the procedure could be as follows:

1.  MPS will be run overnight.
2.  First thing in the morning, the MPS Planners will review the MRP 
Exception Messages.  Actions will be taken to respond to those messages 
and to revise the Planned/Firm Planned Orders and Shop Orders by 10:00 AM 
(for example).
3.  Then, MPS is regenerated based on the revised plan, followed by the 
MRP Explosion.
4.  Once complete, the Procurement people will review the MRP Exception 
Messages for their Items and take appropriate actions to schedule them as 

I hope that these comments help to put this discussion into the proper 

Les Mittman
Office&Fax:    847-459-5763
Cell:               847-858-5235

----- Original Message ----- 
From: "Roy Luce" <lwl@xxxxxxxxxxxxx>
To: "'SSA's BPCS ERP System'" <bpcs-l@xxxxxxxxxxxx>
Sent: Friday, October 20, 2006 11:30 AM
Subject: Re: [BPCS-L] Resell Purchased / Master Schedule ?

My background in MPS goes back to the mid and late 1970's when Arista
Manufacturing Systems out of Winston-Salem, NC developed and marketed 
first MPS module.

The primary usage of MPS is not to "... create smaller subsets of 
or order critical items."  Rather MPS's focus is to manage the 

The production plan consists of a fixed quantity to be produced within a
given timeframe - typically weekly - over a company's planning horizon.
Rather than drive sales demand directly into MRP it is this fixed weekly
production quantity that drives MRP and its planning of purchased and
manufactured sub-components.  Driving MRP off a planned production 
rather than directly from sales orders stabilizes the production floor.
Rarely is it necessary to interrupt production to rush a priority order. 

MPS logic is simple, allowing the production plan to be managed with 
little data analysis.  The first step is to set a weekly production
quantity.  This is done by evaluating sales forecasts and using rough 
capacity planning to determine the feasibility of the production plan. 

In day to day operations booked sales orders consume the uncommitted 
of the production plan (known as the Available to Promise quantity or 
reducing the ATP quantity.  When the ATP goes negative the sales orders'
promise dates are moved to the nearest period with available ATP 
ATP may be in an earlier or later period).  Only when the ATP goes 
and there are no other alternatives, is the production plan number

The primary benefit realized from using MPS is a very high on time 
performance.  In the 1980's and early 90's on time shipment performance
climbed into the high 90 percentile range.

Use of MPS diminished as customers began to demand shorter lead times 
specific date shipments.  Specific date shipment requirements in 
render the MPS ineffective.  The effort to set and manage a daily 
plan takes away from the effort required to meet customer demands.  The 
has been to remove MPS from the picture and drive MRP directly from 
orders.  However there has been a price to pay.

As customer demands change (add this line item, change this ship date,
cancel this order, etc.) so must the daily production plan and since the
daily production plan is driven directly from sales orders it changes 
Managing daily priorities is now the focus and as a result on time 
performance has suffered.  Today firms count themselves doing well if 
ship above 90% on time.  I know of several firms whose objective is to 
90% on time and expend tremendous efforts to make that happen.

Roy Luce

Systems Plus - Midwest

Direct: 847-540-9635
Cell: 847-910-0884
Fax: 847-620-2799
Email: rluce@xxxxxxxxxxxxxxxxxxx

-----Original Message-----
From: bpcs-l-bounces+lwl=ix.netcom.com@xxxxxxxxxxxx
[mailto:bpcs-l-bounces+lwl=ix.netcom.com@xxxxxxxxxxxx] On Behalf Of 
Sent: Friday, October 20, 2006 8:29 AM
To: SSA's BPCS ERP System
Subject: Re: [BPCS-L] Resell Purchased / Master Schedule ?

If you regenerate MRP as often as you regenerate MPS, there should not 
any problems. The requirements of the MRP items will be cought, and al 
necessary orders will be planned to cover these requirements.

As a matter of fact., I dont see as much of a need today to spit items 
between MPS and MRP, given the speed computers can regenerate MRP. My 
understanding is, 20-30-40  years ago, because MRP took hours to run, 
was a need to cut the MRP generation process into a smaller subset of 
capacity critical  or order critical items, the MPS items , and the 
non-critical items:  the MRP items. Any toughts on this?

Daniel Warthold

----- Original Message ----- 
From: "Al Mac" <macwheel99@xxxxxxxxxxx>
To: "BPCS_L discussion" <bpcs-l@xxxxxxxxxxxx>
Sent: Friday, October 20, 2006 1:24 AM
Subject: [BPCS-L] Resell Purchased / Master Schedule ?

  * One rule of thumb says MRP140 needs to "M" Master Schedule End 
  that we manufacture and sell for customers, so that MRP will 
  what's needed of all components to be manufactured or purchased.
  * Another rule of thumb says raw material that we purchase to be used 
  components of the manufactured parts, nor any sub-components, should 
  be "M" coded, just the end items that we sell the customers.
  * A dispute has come up with respect to what is the correct Master
  Schedule coding for items that are coded purchased, but can also be 
  customers as THEIR service or repair parts?

  It has been several years since we had MRP education, so different 
  memories stray into disagreements needing clarification.

  I had thought that when the raw materials show up as components of 
  scheduled items, currently on customer orders, that MRP will 
  calculate how many we need thanks to both dependent and independent
  requirements, but if a customer orders a supply of our raw materials, 

  are not currently needed due to being in the BOM of master scheduled
  active items, then by not having these raw materials master 
  have effectively told MRP to ignore these requirements, and that 
  extra items coded as master scheduled did no harm to MRP.

  We are on BPCS 405 CD mixed mode.
  We run MRP500 then MRP600 by facility, with a few extra runs of 
  thanks to a prior thread on BPCS-L regarding parts complexity.
  Our BOM has several levels.  We used to be heavy into DRP resupply 
  but that part of our business is now about dad.

  Al Macintyre
  BPCS/400 Computer Janitor ... see
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