How do I pause a source from creating items during an specific time?

[felipe_glz]

[ FlexSim 20.0.8 ]

I've got a simulation that runs by 4 hours and later another 4 hours. There's a processor's breakdown for 1 hour. I need the source stops sending elements, just for 1 hour, to the queue because the processor cannot do its work, I want my system to resume after the breakdown for another 4 hours and not reset it. The source works with an inter-arrival time according to a normal distribution with mean 3.4 min and sd 0.5 min. Could someone help me, please?

[joerg_vogel_HsH]

It is a task for a timetable. You find it in the toolbox.

[jason_lightfootVL7B4 · Accepted solution]

A breakdown usually means its unplanned and therefore random. Is this the case or is it more a scheduled downtime for planned maintenance or similar? As @Jörg Vogel suggests you can use a timetable for shift patterns and scheduled downtime.

If you want to add an unplanned stop/breakdown then it's the (challengingly named) MTBF/MTTR in the toolbox:

Attached is a model where the processor stops the source during a breakdown if its label "stopsource" is set to 1 (or higher), and not if it's set to zero. This could be done directly from the processor's triggers (bad), or via a message to the source (better) but I've chosen to call/execute labels on the source "stop" and "resume" (maybe even better).

Example_processorBreakdownStopsSource.fsm

[felipe_glz]

Thanks, @jason.lightfoot. It's good idea, but I think it doesn't work in my model, because I'm using Item List to assign elements, so the queue isn't connected to the processor. I'm simulate a restaurant where people arrive and wait to be attended, but those whose wait more than 5 minutes in queue leave the system. I tried with your example but it didn't work, just one element (person) is processed.

[jason_lightfootVL7B4]

That sounds more like pulling from a list of available tables with a timeout of 5 minutes.

So is it the source of people arriving at the restaurant that you want to control here. That source could just check if an object was stopped or not a simple decision after it that send to a sink - or you could schedule your arrivals to occur during the opening hours which sounds more logical.

If you're able to share your model here or in a private post then we could better discuss its specfics.

[felipe_glz]

Here is my model. Thanks.

item list model.fsm

[jason_lightfootVL7B4]

Then my original approach works - it sounded like you were using process flow with lists - sorry.

Model attached.

item-list-model_jl.fsm

[felipe_glz]

Thank you. Just one last question. Is it possible that the processor during breakdown doesn't have elements (customers) and send it directly to sink of unhappy customers? I figure out when there's a breakdown the customer's time in system and in queue still counting. Or do you think that it is better schedule the arrivals in this case?

[jason_lightfootVL7B4]

Honestly if there is nothing special about each arrival you could just close the input of the queue and have a sink connected to the source on output port 2. This way the arrivals will stop but the service desk can process those in the queue before going off shift. Removes the need to stop the source and might be more representative of what actually happens?

[felipe_glz]

Actually, I wanted to simulate something more real as it'd occur in reality. Thank you for answering me.