topic Re: how to make a flow such that the item from the conveyor moves to the third processor only when first to processor is not available (not the processor are connected in series) in FlexSim Forum

how to make a flow such that the item from the conveyor moves to the third processor only when first to processor is not available (not the processor are connected in series)

gilbertjerald1993 — Tue, 16 Aug 2016 09:20:22 GMT

in my model three processor are attached with a conveyor , wherei have added third processor as a back up ,in my model the first two processor have the capacity to handle 133% of incoming products , by this given data the idle time of the first two machine should be less when compare to the third processor and the amount of work done should be more for the first two machine when compare the third processor ,for that what should be the changes to be done in my model or any coding want to be change if else please send me the coding that is to be change. i have attached my model for your referencejohnson-pharamaceutical-new-model.fsm

Re: how to make a flow such that the item from the conveyor moves to the third processor only when first to processor is not available (not the processor are connected in series)

adrian_haws — Tue, 16 Aug 2016 15:08:06 GMT

Hi Gilbert,

You can actually accomplish this using triggers, without any coding. One way to do this is by setting a trigger in the source for "Set Item Type by Percentage", where you can specify how many item types and what percentage of each will be set. Then in the "On Arrival" trigger of the decision point, select "Send Item By Case". Leave the default case function as getitemtype(item). Then add three cases, or however many ports and item types you set. I've attached an example, but you'll probably want to change the values.

Re: how to make a flow such that the item from the conveyor moves to the third processor only when first to processor is not available (not the processor are connected in series)

jeff_nordgren — Tue, 16 Aug 2016 18:17:53 GMT

@gilbert jerald

Hi,

Attached is your model with the changes that I have made. Basically all I changed were the connections. And I moved the DP and the conveyor output port (deleted the other 2 output ports).

All flowitems are sent to the conveyor output port (ExitTRansfer26). From there, they are sent to the first available processor in the order of the output port connections.

And that's pretty much it. If you have any questions, please let me know. Here is the model: johnson-pharamaceutical-new-model-jn1.fsm

Re: how to make a flow such that the item from the conveyor moves to the third processor only when first to processor is not available (not the processor are connected in series)

gilbertjerald1993 — Wed, 17 Aug 2016 06:20:18 GMT

thank you sir for your reply

i have understood what you have model sir , you have used one exit port, can you please tell me is there any way to get this answer with my old connection that is with three exit port because the exercise which i am doing from the flexsim text book has propose to model like this.

Re: how to make a flow such that the item from the conveyor moves to the third processor only when first to processor is not available (not the processor are connected in series)

gilbertjerald1993 — Wed, 17 Aug 2016 06:33:50 GMT

thank you sir for your reply

but in my problem they have not mention any particular percentage for each machine ,as per your model 40% of item will move to first two machine and 20%of item will move to third machine.

"this the question which i am modeling, i have attach for you reference sir" (As the largest supplier of over-the-counter medications, Johnson is redesigning its cold remedy line for higher capacity in time for the upcoming flu season. The plan is for the packing line to be completely re-designed. The new plan, conceived by the corporate packaging group, is based on the “greedy” concept. In that design, boxes of individual doses are taken off the main conveyor line by the first test/wrap machine. A second test/wrap machine takes off boxes further down the conveyor. The boxes arrive in the packing area at an average rate of 60/min. The wrap machines are rated at an average of 40/min. Based on average rates, the first two machines can handle 133% of the incoming boxes rate; however, a third will also be added as a backup. The plant engineering manager has asked you to validate the design before the plant commits to the proposed production rate.

Re: how to make a flow such that the item from the conveyor moves to the third processor only when first to processor is not available (not the processor are connected in series)

gilbertjerald1993 — Wed, 17 Aug 2016 06:34:25 GMT

Re: how to make a flow such that the item from the conveyor moves to the third processor only when first to processor is not available (not the processor are connected in series)

Brandon_Peterson — Wed, 17 Aug 2016 14:49:00 GMT

Gilbert,

Here is a possible solution for you. On the conveyor I placed a decision point at each of the first two exits. The decision points look at the processor for that exit and if it is empty they send the flowitem out the exit. This was not necessary for the third processor as it is at the end of the conveyor.

This does not produce the anticipated results that you described in your question. This is a result of how the arrival rate of the flowitems and the process times at the processors interact and the fact that if a flowitem is missed by the first two processors then it will wait at the third processor until it is available.

If you need the system to perform more closely to your expected results then you may need to incorporate some more logic. If the processor is capable of pulling flowitems from a length of coneyor (as opposed to a single point like the current model) then you could place another (or more) decision points for each processor along the exit section of the conveyor.

I hope this gets you going again,

Brandon

Re: how to make a flow such that the item from the conveyor moves to the third processor only when first to processor is not available (not the processor are connected in series)

gilbertjerald1993 — Thu, 18 Aug 2016 06:46:57 GMT

thank you for your reply sir

i have a doubt with a changes that you have done in my model

in decision point in ,on arrival you have selected "send item". in that ,how did get this" !content(centerobject(current, 1))" condition statement whether you have made coding in that or by selection any option in that.

Re: how to make a flow such that the item from the conveyor moves to the third processor only when first to processor is not available (not the processor are connected in series)

joerg_vogel_HsH — Thu, 18 Aug 2016 16:35:44 GMT

In the combination of a conveyor and different distances to the exit points, the decision point has to control the allocation of items not only by the current state of the processor at the exit points but by the states the processor is going to have, when the item arrives at the exits. Then there might be a delay at the processor and the whole process on the conveyor might stop. Then the item must divert to the next exit on the conveyor to prevent a whole collapse of the system. A forecast might reduce the failure of the system at the decision point, but there are still the randomly events you can't evaluate for the future. This leads to a last check right before the item leaves the conveyor to divert it to another exit, maybe your backup station. There has to be a cache in front of the backup processor to store all items until a breakdown is repaired. Otherwise the items could go to the entry of the conveyor by a cart or by another conveyor. Also a good practice is to place a queue in front of the processors to supply at least one item when the processor finishes its current item.

Re: how to make a flow such that the item from the conveyor moves to the third processor only when first to processor is not available (not the processor are connected in series)

jeff_nordgren — Thu, 18 Aug 2016 17:52:05 GMT

I'm not sure I understand what you are asking. The model I attached is your model with the changes that I made. Do you have a specific question about what change(s) I made to your model?

Because the flowitems are sent to the first available processor, in order of the output port connections, only the "left over" flowitems should ever go to the third processor.

Re: how to make a flow such that the item from the conveyor moves to the third processor only when first to processor is not available (not the processor are connected in series)

gilbertjerald1993 — Fri, 19 Aug 2016 06:55:41 GMT

thank you sir for your reply @ jeff nordgren

Re: how to make a flow such that the item from the conveyor moves to the third processor only when first to processor is not available (not the processor are connected in series)

jeff_nordgren — Mon, 22 Aug 2016 20:54:30 GMT

@gilbert jerald

Take a look at the attached model. If there is something you need explained in more detail, please ask.

Is this what you were looking to do? In this model, no flowitems should ever go to Processor7 unless at the time the flowitem hits DP3, the other two processors are busy.

Again, let me know if you need more information on how the model work.

johnson-pharamaceutical-new-model-jn2.fsm

Re: how to make a flow such that the item from the conveyor moves to the third processor only when first to processor is not available (not the processor are connected in series)

Brandon_Peterson — Tue, 23 Aug 2016 23:28:54 GMT

Gilbert,

the code "!content(centerobject(current, 1))" was code that I entered in manually. I simply means that there are not ("!") any objects contianed ("content") by the center object connected to the first center port ("centerobject(current, 1)").

It checks the processor to see if it is empty (with the code in question) and if it is empty then it sends the flowitem to the processor.

I hope this clears things up for you,

Brandon