Patients waiting for elevator

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laetitia thomas asked Jun 23, '16 Matthew Gillespie commented Jun 28, '16

Patients waiting for elevator

Hi,

I developped a small model with FlexSim HC using an elevator bank of 10 elevators.

The model works when the interarrival time of patient is high enough, but when one of the elevator reaches its maximum capacity and there are still people waiting, these persons will wait until the same elevator is available, instead of calling another elevator…(may be because when they arrived, they are automatically "dispatched" to this elevator even if there is no more space in the elevator)

Here is my model :modele-ascenseurs.fsm

On my computer, I see this problem at time 1.6 for example.

Thank you for your help !

Laetitia

Software Version:

FlexSim HC 5.0.12

healthcare elevator flexsim hc

modele-ascenseurs.fsm (534.1 KiB)

5 |100000

Attachments: Up to 12 attachments (including images) can be used with a maximum of 23.8 MiB each and 47.7 MiB total.

Answer 1 · 2016-06-27T19:51:34Z

Cliff King answered Jun 27, '16 Matthew Gillespie commented Jun 28, '16

Hi Laetitia,

The model may be small, but the customized logic in the model isn't. After spending most the morning trying to figure out what was going on, I discovered a user-defined function called "attenteAscenseur" buried deep within the On Arrival trigger of the elevator call node's standard option named "Send Message to Request Elevator". I'm not sure whether this function call is the cause of an elevator not responding to travelers arriving at the node after the actively loading elevator reaches max capacity, but I'm hesitant to spend much more time debugging this model for fear there have been other customizations to the model that are not obvious to me. I've attached a small test modeelevator-bank-test.fsml that demonstrates patients will successfully call for another elevator when the actively loading elevator reaches capacity. There are two elevators in the model that each have a capacity of only two patients. Notice that the 5th patient to arrive (the one in the blue shirt) can't get on elevator 1 because the two guys in front of him take it, so he successfully calls for elevator 2.

elevator-bank-test.fsm (81.8 KiB)

· 1

5 |100000

Attachments: Up to 12 attachments (including images) can be used with a maximum of 23.8 MiB each and 47.7 MiB total.

laetitia thomas commented · Jun 28, 2016 at 06:57 AM

Hi Cliff,

Most of the customized logic is there in order to save results such as th time spent waiting for elevator and the number of patients waiting.

So I think I found the function that caused the problem : it's a event function happening only on reset "Set nb Ascenseurs", I wrote in order to limit the number of elevator that can be used (if I just change the number of active members, the patients still use all elevators...)

So thank you for your answer, I will try to find another way to reduce the number of elevators avalaible.

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