topic Re: Delay flow object entry to processor based on previous item in FlexSim Forum

Delay flow object entry to processor based on previous item

dan_b6 — Fri, 16 Jul 2021 20:03:52 GMT

[ FlexSim 21.1.4 ]

I downloaded the trial and went through the basic tutorial a few weeks ago and i'm trying to model something now. Where I'm getting stuck is trying to model an inline machine where multiple items can be processed at a time so long as they are spaced apart by a certain time interval (lets say 10 seconds).

In other words, I want to stop a flow item from entering a processor until the previous flow item has been in that processor for at least 10 seconds. If the previous item has been in there for longer than 10 seconds, the subsequent item will flow right in. If not, it will stop until the duration after entry of the predecessor is at least 10 seconds. I hope this makes sense.

Thank you in advance for any pointers or solutions!

Re: Delay flow object entry to processor based on previous item

eric_m3 — Fri, 16 Jul 2021 22:08:42 GMT

HI @Dan B6, glad to hear you're giving Flexsim a try! I built a simple model showing one way this could be done. Using process flow, I create items in a queue and then have them enter a Zone. In the "Zone:10s" activity, I checked the box "Use Max Content" and set it equal to 1. This makes it so only 1 token will be allowed in the zone at a time. Here's where I move the item into the processor and then delay for a given time. Now tokens will have to wait their turn before moving their connected item into the processor. Of course, if there aren't any tokens in the zone, they will be free to move on with no delay. Let me know if you have any questions.

Processor Wait 10 Seconds.fsm

Re: Delay flow object entry to processor based on previous item

dan_b6 — Fri, 16 Jul 2021 23:18:17 GMT

Thank you @Eric M ! I suspected this would require utilizing a process flow. I appreciate your help

Re: Delay flow object entry to processor based on previous item

dan_b6 — Sun, 18 Jul 2021 20:06:08 GMT

@Eric M HI Eric. Another question if you don't mind. How would I set this up in between two processors? In my model, there is not a queue before the processor that needs the 10s delay. Thanks again for your help

Re: Delay flow object entry to processor based on previous item

eric_m3 — Mon, 19 Jul 2021 15:33:05 GMT

I would use an "Event-Triggered Source" in process flow instead of the inter-arrival source used before. For the "Object" in that source, I would use the sampler to select the first processor in the flow and then choose the "SendToPort" event. Now a token will be created in process flow for each item that is leaving Processor2.

The last thing to do is to make sure there's a label on the token that references the item in the 3d model. This is important so we can use the "Move Object" activity later in the flow (without a reference to an item, the token wouldn't know what to move). We can do this in the Label Assignment / Match Value section of the source. For the event "Releasing Item" you can create a label called "item" (or anything else you'd like so long as the Move Object activity references that same label name) and choose "assign" for the Operation. Now a label called "item" will be on the token that references the item in the 3d model. Hopefully that makes some sense. I'll attach the updated sample model.

processor-wait-10-seconds_1.fsm