topic Re: Maintain item gap at merging conveyors and managing slugs. in FlexSim Forum

Maintain item gap at merging conveyors and managing slugs.

farah_najihah_a — Thu, 19 May 2022 08:55:03 GMT

[ FlexSim 22.1.1 ]

Hello, I have some problems with my model. but I have no idea since I am not yet well verse in process flow, so most of my configurations are without process flow.

1st is I am trying to simulate something where I need the items to merge at point 1 and 2 as shown in picture attached. but how do I configure so they wont clash each other? How can I maintain the gap between the items? I have tried using sensors and decision points but it does not work maybe I configure it wrongly.

2nd is I need the items to continue and overflow even when the conveyors (they are in round robin terms) are full as shown in 2nd picture. I tried using sensors but it still get stucked. I tried the same using simpler model, it works to my favor but not in this model.

I attached both my simpler model with the sensors and my complicated model. any advise would be very helpful and much appreciated. Thank you!

Modified test model trial 1.fsm

block-test-fm.fsm

Re: Maintain item gap at merging conveyors and managing slugs.

kavika_faleumu — Mon, 23 May 2022 22:26:29 GMT

Hey @Farah_najihah A, I'm not sure what you're asking with your first question about items clashing; do you just want space between the flowitems as they travel?

As for your second question, if you want to maintain a round robin operation for type 2 flowitems, you can assign a label (in my example I used "Lane" as my label) that will "Round Robin") the flowitems instead of using the "Send Item" event. This previous post inspired this solution for labeling. Essentially, you have the DP keep track of the "type2Count" and increment it each time you assign a Lane. You need to assign a different value for type 1 flowitems so when they pass over the DPs they don't throw exceptions.

if (item.Type == 2) {
int numOutput = current.outObjects.length;
current.labels.assert("type2Count", 0).value++;
item.Lane = ((current.type2Count-1)%numOutput)+1;
}
else {
item.Lane = 0;
}

For the DPs accepting the flowitems into different lanes, I used this conditional statement:

item.Lane == 1 && current.centerObjects[1].stats.state().value != 4

The first part is checking the Lane label on the flowitem. If it's is 1, send it down this lane (2 for the next lane, and so on).

The second part checks the state of the photo eye (PE) in the lane. If the PE is in the blocked state (4), then we don't want to send a flowitem down this lane. When a queue starts stacking up, it will eventually block this PE and not allow any boxes to go down that lane, thus not blocking the conveyor belt flow like before.

conveyor flow.fsm

Also, here's a smaller model to help see how it works: testing-code.fsm

Re: Maintain item gap at merging conveyors and managing slugs.

Jeanette_Fullmer — Thu, 26 May 2022 22:01:33 GMT

Hi @Farah_najihah A, was Kavika F's answer helpful? If so, please click the "Accept" button at the bottom of their answer. Or if you still have questions, add a comment and we'll continue the conversation.

If we haven't heard back from you within 3 business days we'll auto-accept an answer, but you can always unaccept and comment back to reopen your question.