unit conversion

[mdsdoha]

Dear Concern

Hi!

I am totally apprentice of this software. Can anybody describe with example that how unit can be convert to other name? such as "kg" to "tonnes", "chicken" to "KG". What is the precondition to convert units based on certain variable.

waiting for kind response.

[Administrator]

If you have a variable that is something like

"distance in inches" and you want to convert to mm, create a constant called "mm per inch" = 25.4.

Now in your model, you can have

distance in mm = distance in inches * mm per inch

The units are
mm = in * mm / in

Hope this helps.

Tony.

[mdsdoha]

Dear Concern

Thanks for your link. Still I have doubt and I failed to apply in my model. I am working on poultry supply chain modelling. Briefly, initially "eggs" enter the system then convert it to "chicks" then convert into "chicken". after that chicken produces wastage which is in "Kilograms". Wastage diverted in three different things of fertilizer, fish feed and bio gas. "tonnes", "KGS" and "cubic metre" are the unit for them. Could you please help me out how I convert all these units based on objects. If you want, I can send you my model. I am not sure how can I attach my model here? Waiting for kind response.

Regards

[Administrator]

To convert from egg to chick, create a variable
chicks per egg = 1 {units, chick/egg}

Then from chicks to chickens,
chickens per chick = 1 {units, chicken/chick}

Then chickens to wastage
wastage in kg {units : kg} = number of chickens {units : chickens} * wastage per chicken {units : kg/chicken}

Now from wastage to tonnes
wastage in tonnes {units : tonne} = wastage in kg {units : kg} * tonne per kg {units : tonne/kg}
wastage in m3 {units : m3} = wastage in kg {units : kg} * cubic metres per kg {units : m3/kg}

Hope this helps. Make sure you get the units correct, they really are a vital part of any model.

Tony.

PS. Feel free to post the model here (click the "Upload attachment" link).

[mdsdoha]

Thanks. I will try accordingly.

Could you please help me to find out "BEER GAME MODEl" in Vensim version? Where can I find it?

[Administrator]

These might help.

http://www.ventanasystems.co.uk/forum/v ... =38&t=3026

http://www.beergame.lim.ethz.ch/

http://www.simcon.de/simcon-seminare/the-beer-game

http://web.mit.edu/jsterman/www/SDG/MFS/simplebeer.html

[mdsdoha]

Dear Sir

I have tried to convert the unit chicks into eggs but failed to do so. Here, I have attached a small model where I wanted to convert chicks to eggs but its giving me RHS errors. Would you mind to show the correct code in my model? appreciate your help. thanks

To convert from egg to chick, create a variable
chicks per egg = 1 {units, chick/egg}

Then from chicks to chickens,
chickens per chick = 1 {units, chicken/chick}

Then chickens to wastage
wastage in kg {units : kg} = number of chickens {units : chickens} * wastage per chicken {units : kg/chicken}

Now from wastage to tonnes
wastage in tonnes {units : tonne} = wastage in kg {units : kg} * tonne per kg {units : tonne/kg}
wastage in m3 {units : m3} = wastage in kg {units : kg} * cubic metres per kg {units : m3/kg}

Hope this helps. Make sure you get the units correct, they really are a vital part of any model.

Tony.

PS. Feel free to post the model here (click the "Upload attachment" link).

[Administrator]

First, "eggs in" cannot be chicks*chicks/week (chicks squared per week). That makes no sense. It should be measured in eggs/week.

"Parent eggs" should be measured in "eggs".

You have the units for time to be "month" but I think you really need "week".

"eggs per gp" should be measured in "eggs/chick/week" (eggs per week per chick), not "Chicks/Eggs"

"Initial eggs" should be measured in "eggs".

See the attached model. I've changed none of your equations, just corrected the units so that they make sense (and now it passes the units check).

A few notes,
Remember that stocks are "usually" measured in "eggs", "chicks", "widgets" etc.
The rates that flow in/out should be "eggs/week", "chicks/week", "widgets/week" etc.
Converting should also make sense, so to convert from chicks to eggs, you need "eggs per chick per week".
Above all, the units need to make sense (so "chick*chick/week" would not be suitable).

Hope this helps.

[mdsdoha]

Thanks so much. Now I understand where was my problem? thanks again


A few notes,
Remember that stocks are "usually" measured in "eggs", "chicks", "widgets" etc.
The rates that flow in/out should be "eggs/week", "chicks/week", "widgets/week" etc.
Converting should also make sense, so to convert from chicks to eggs, you need "eggs per chick per week".
Above all, the units need to make sense (so "chick*chick/week" would not be suitable).

Hope this helps.[/quote]

[mdsdoha]

Dear Tom

Hi!

Thanks for your last explanation of unit conversion. Now I have little confusion about timestep. Say, I need 21 days to hatch a egg that means if I use time step 1, it will require 3 time step, isn't it? You have sent me a model before where you put TIMESTEP between two Levels. My question is why did you put it? I tried to change the value from there and it is automatically change the whole setting; I mean time step will change for all variable. Could you please explain what others usage of time and time step as regards to put it in the model though it is in hidden information. One more little thing, if somehow I put time or timestep variable in the model, I can not delete it. how can I delete it?

thanks

First, "eggs in" cannot be chicks*chicks/week (chicks squared per week). That makes no sense. It should be measured in eggs/week.

"Parent eggs" should be measured in "eggs".

You have the units for time to be "month" but I think you really need "week".

"eggs per gp" should be measured in "eggs/chick/week" (eggs per week per chick), not "Chicks/Eggs"

"Initial eggs" should be measured in "eggs".

See the attached model. I've changed none of your equations, just corrected the units so that they make sense (and now it passes the units check).

A few notes,
Remember that stocks are "usually" measured in "eggs", "chicks", "widgets" etc.
The rates that flow in/out should be "eggs/week", "chicks/week", "widgets/week" etc.
Converting should also make sense, so to convert from chicks to eggs, you need "eggs per chick per week".
Above all, the units need to make sense (so "chick*chick/week" would not be suitable).

Hope this helps.

[Administrator]

It might be a good idea if you did the PLE tutorial at
http://www.public.asu.edu/~kirkwood/sysdyn/VenPLE.pdf

Page 13 mentions what time step is.

More information is also at
http://www.vensim.com/documentation/ind ... sdates.htm

Hope this helps.

Tony.

[mdsdoha]

Thanks. I have gone through your documents which I have already read it but confusion is still same, why don't we use different time step in same model?

by the way, here I am sending revised model having problem with conversion. As par your guidance, I did solve some of my problems but when three different unit name meet in a point, how can I solve? Say, eggs converted chicks then immediately convert as chicken. so, three different things involve in one point. number of eggs minus number of chicks will be "Parent Eggs" level and number of chicks minus number of chicken will be broiler farms level. would you mind to see trhsi model again and provide required suggestion.


Regards

Doha

Dear Tom

Hi!

Thanks for your last explanation of unit conversion. Now I have little confusion about timestep. Say, I need 21 days to hatch a egg that means if I use time step 1, it will require 3 time step, isn't it? You have sent me a model before where you put TIMESTEP between two Levels. My question is why did you put it? I tried to change the value from there and it is automatically change the whole setting; I mean time step will change for all variable. Could you please explain what others usage of time and time step as regards to put it in the model though it is in hidden information. One more little thing, if somehow I put time or timestep variable in the model, I can not delete it. how can I delete it?

thanks

First, "eggs in" cannot be chicks*chicks/week (chicks squared per week). That makes no sense. It should be measured in eggs/week.

"Parent eggs" should be measured in "eggs".

You have the units for time to be "month" but I think you really need "week".

"eggs per gp" should be measured in "eggs/chick/week" (eggs per week per chick), not "Chicks/Eggs"

"Initial eggs" should be measured in "eggs".

See the attached model. I've changed none of your equations, just corrected the units so that they make sense (and now it passes the units check).

A few notes,
Remember that stocks are "usually" measured in "eggs", "chicks", "widgets" etc.
The rates that flow in/out should be "eggs/week", "chicks/week", "widgets/week" etc.
Converting should also make sense, so to convert from chicks to eggs, you need "eggs per chick per week".
Above all, the units need to make sense (so "chick*chick/week" would not be suitable).

Hope this helps.

[Administrator]

ok, start with "FARM IN RATE". What is this, and what is it measured in?

[mdsdoha]

Farm in rate measure how many chicks enter into ultimate broiler farmer as chicks and these chicks will grown up as chicken later.

ok, start with "FARM IN RATE". What is this, and what is it measured in?

[Administrator]

I've attached a model that will hopefully help you a little.

[mdsdoha]

Thanks for your time to revised the model. I am really sorry to have so many question in my mind as a learner.
I have three question in my mind which I have asked in the attached model. These questions are related to "using rate variable instead of auxiliary", "capacity and target variable" and " level which used as last point of a model".

thanks for your continuous help to learn Vensim.

I've attached a model that will hopefully help you a little.

[Administrator]

Qs: 1. why do not you use rate variable or bulb as you used auxiliary? Is there any particular reason behind it?

I was trying to do this quickly.

Q2. How can I add capacity and target variable? I want to set a target production which might hamper with existing capacity; at the same time capacity will be increase after certain time step. Can you please check and suggest what I have tried to do for target and capacity?

See http://www.vensim.com/documentation/ind ... ?mgu05.htm

Q3. If I click check model, it shows total revenie level did not use in this model. Is this error ignorable? We might need to put few end level which will not flow either way.

It is just a warning. If you want it to disappear, tick "supplementary" in the equation editor for it.

[mdsdoha]

Thanks and it will help me to understand few important things.

Qs: 1. why do not you use rate variable or bulb as you used auxiliary? Is there any particular reason behind it?

I was trying to do this quickly.

Q2. How can I add capacity and target variable? I want to set a target production which might hamper with existing capacity; at the same time capacity will be increase after certain time step. Can you please check and suggest what I have tried to do for target and capacity?

See http://www.vensim.com/documentation/ind ... ?mgu05.htm

Q3. If I click check model, it shows total revenie level did not use in this model. Is this error ignorable? We might need to put few end level which will not flow either way.

It is just a warning. If you want it to disappear, tick "supplementary" in the equation editor for it.

[mdsdoha]

Hi!

I tried to do unit conversion in consecutive three level variable but failing to replicate this. I want to convert from Eggs to Chicks to Chicken to Money. All these changes will come one after. Could anybody help me to do so?

Say,

Eggs in- Eggs (level)- Chicks out - Chicks (Level) - Chicken out -Chicken (Level)- Money out


Please help!

[Administrator]

To convert eggs to chick, create a variable which is called "chicks per egg"

chicks per egg = 1
Units : chick/egg

I'd assume you have a hatching rate maybe measured in eggs/day. Now multiply the number of hatching eggs by this.

hatching rate = <something>
Units : egg/day

New chick rate = hatching rate * chicks per egg
Units : chick/day

To convert chicks to chicken, do the same thing.

chicken per chick = 1
Units : chicken/chick

And to convert to money,

cash per chicken = 10
Units : dollar/chicken

[mdsdoha]

Dear Sir

I have tried same way as you have written but did not work. I think, I found the reason but cannot solve it. Say, Egg is a level, input of eggs level is eggs/week, and output as Chicks/week because immediate level variable is Chicks. Then the same happen immediately output is chicken/week. please have a look of the below model if possible. Thanks

To convert eggs to chick, create a variable which is called "chicks per egg"

chicks per egg = 1
Units : chick/egg

I'd assume you have a hatching rate maybe measured in eggs/day. Now multiply the number of hatching eggs by this.

hatching rate = <something>
Units : egg/day

New chick rate = hatching rate * chicks per egg
Units : chick/day

To convert chicks to chicken, do the same thing.

chicken per chick = 1
Units : chicken/chick

And to convert to money,

cash per chicken = 10
Units : dollar/chicken

[Administrator]

I've had a quick look and updated a few things. Take a look and see if you understand it ok.

[Stephen Carol]

Hi
I have a common question.
Can I convert to Imperial measurements? like here: https://oneconvert.com/unit-converters/ ... /kg-to-lbs

[Administrator]

Yes. Create an unchangeable constant called "kg per lb", give it the correct units (kg/lb) and value (0.453592). Then you can use it to convert any kg or lb measurements in your model.