Calculate Duration from Custom Fields

[Scott]

Greetings

I have some machinery which I need to keep track of and thought project
might be the ticket. Heres the problem

The machines have a finite life span and the life is dependant on the total
electrical power they use (Kinda like a light bulb), once they get close to
the the expected power usage we like to take them out of service before they
fail. We have many different machines with different lifes. I also know the
demand on each machine per unit time say per day.

So from this information I can determine when the machine will fail and
schedule replacement and order spare machines

I would like to make a simple MS Project document to keep track of all the
machines and the spare replacement machines. It will help us keep history as
well as perdict when we need to order spares.

So the question. I would like to be able to calculate the duration in
project from two other custom fiields. For example

Duration=Expected Life/Demand

Can project calculate task duration from custom field.

Am I barking up the wrong tree

Thanks
Scott

 

[John]

Greetings

I have some machinery which I need to keep track of and thought project
might be the ticket. Heres the problem

The machines have a finite life span and the life is dependant on the total
electrical power they use (Kinda like a light bulb), once they get close to
the the expected power usage we like to take them out of service before they
fail. We have many different machines with different lifes. I also know the
demand on each machine per unit time say per day.

So from this information I can determine when the machine will fail and
schedule replacement and order spare machines

I would like to make a simple MS Project document to keep track of all the
machines and the spare replacement machines. It will help us keep history as
well as perdict when we need to order spares.

So the question. I would like to be able to calculate the duration in
project from two other custom fiields. For example

Duration=Expected Life/Demand

Can project calculate task duration from custom field.

Am I barking up the wrong tree

Thanks
Scott

Scott,
Well you might be barking up the wrong tree. It doesn't sound like you
really plan to create a schedule per se. Since the machine life span
("duration") is based on a simple formula, it seems like Excel might be
a better choice.

However to answer your question, in Project you can create a custom
field with a formula but you can't directly change the normal Duration
field with the result of that formula. You could however, use the
formula to set the value of a spare duration field (e.g. Duration1).

John
Project MVP

 

[Jim Aksel]

Let me first answer your question, and then make a suggestion.
Yes, Project can calculate durations based on custom fields. One way to do
that is to have these custom fields evaluate to dates.

There are several functions built into Project that allow these types of
calculations. Here is how to find them. Insert a custom field, right click
on it, select Customize Fields. In the box that opens select "Formula"....
So, now you on a form that allows input of a formula. At the bottom of that
window is a button that says "Function". Click that and look for Date/Time
and Microsoft Office Project. Both of these offer formulas that can be used
to evaluate duration.

Suggestion: Since you know the life of the machine (x hours), you could
create a formula to display the remaining life in hours using another
formula. That is, you know which tasks are assigned to the resource and how
many hours the machine will burn during the duration of each task. So, you
might be able to cummulate these hours (to the left of a status date line)
and subtract that from the life. I would do it on the Resource Usage view.

At any rate, you can use project to assist you. The same could be done in
Excel. It is really a matter of what you want to scratch you head and think
about.
--
If this post was helpful, please consider rating it.

Jim
It''s software; it''s not allowed to win.

Visit http://project.mvps.org/ for FAQs and more information
about Microsoft Project

 

[John]

Let me first answer your question, and then make a suggestion.
Yes, Project can calculate durations based on custom fields. One way to do
that is to have these custom fields evaluate to dates.

There are several functions built into Project that allow these types of
calculations. Here is how to find them. Insert a custom field, right click
on it, select Customize Fields. In the box that opens select "Formula"....
So, now you on a form that allows input of a formula. At the bottom of that
window is a button that says "Function". Click that and look for Date/Time
and Microsoft Office Project. Both of these offer formulas that can be used
to evaluate duration.

Suggestion: Since you know the life of the machine (x hours), you could
create a formula to display the remaining life in hours using another
formula. That is, you know which tasks are assigned to the resource and how
many hours the machine will burn during the duration of each task. So, you
might be able to cummulate these hours (to the left of a status date line)
and subtract that from the life. I would do it on the Resource Usage view.

At any rate, you can use project to assist you. The same could be done in
Excel. It is really a matter of what you want to scratch you head and think
about.

Jim,
Just to clarify, formulas in custom fields can calculate duration, but
they cannot calculate the normal Duration field, which is what I think
Scott wants to do.

John

 

[Scott]

Thanks for your input folks. Very helpful in pointing me in the right
direction.
I think its back to excel and a simple bar graph
Scott

 

[Jim Aksel]

I agree. My response stated to insert a custom field implying the Duration
field wasn't going to work for him. I should have been much more specific
and stated it like you did.

It looks like Scott is off to Excel ...

Thanks for keeping everything clear.

 

[John]

I agree. My response stated to insert a custom field implying the Duration
field wasn't going to work for him. I should have been much more specific
and stated it like you did.

It looks like Scott is off to Excel ...

Thanks for keeping everything clear.

Jim
Normally I would have passed it over but Scott seemed like a very new
Project user and its real easy to get confused. Hey, I've been working
with Project for many years and I'm still confused

We appreciate your contributions to the newsgroup.

John

 

[John]

Thanks for your input folks. Very helpful in pointing me in the right
direction.
I think its back to excel and a simple bar graph
Scott

Scott,
You're welcome. Project might work for you but from your post it just
didn't sound like you need Project's scheduling capability.

John
Project MVP