Use a combiner or processor to send parts according to quantity put a delay

[varun_r2]

[ FlexSim 18.1.1 ]

conceptpn-rev-1.fsm

I am trying to use two ports 1 and 2 to connect to a single port downstream.

Right now I have a photo eye which when block would send parts to an accumulation bed(eventually Port 2). Soon the above happens I want my Gate2(we can use combiner or a processor) to send 20 parts via Port 1 then wait for 2 seconds to switch to Port 2 and send 20 parts via Port 2, looping this until all the content on Port 2 (i.e accumulation bed) is clear, soon the content is clear it should be a normal operation i.e my Gate 1 should send parts via port 1. And when I back up again until photo eye PE 1, the above process should kick in.

As you see I am trying to use process flow. I want to understand a best way to approach this. Let me know if any further explanation. Thank you.

[varun_r2]

@Joshua S I am not able to see your comment. But I think you asked whether my conveyer backs up. Yet it would I just have not used other process in the downstream yet and not have updated MTBR MTBfs. I would just back it up by manipulating the process time for the trimmer to 10 secs to see if the logic works.

[joshua_s]

I deleted my comment because I didn't run your model long enough to see it backup, but I saw that it eventually does. I'll take a look at it later and see if I can make a suggestion.

[joshua_s]

@Varun Rawal

See if these changes are what you wanted. All changes I made were in process flow with some labels added to Gate2

13234-conceptpn-rev-1.fsm

[varun_r2]

@Joshua S Thanks for the help.

I can see that the trimmer is used as a state change to trigger the Gate2 shift. However, when the trimmer is not down and everything is running the parts would get stuck in the accumulation bed (run the current model for some 3800 seconds to check)

Now what i have thought is I will have photo eye called PE4 right before Gate2 in Port 2 as shown and use it to decide whether my Gate2 should activate (meaning when activated i.e PE4 is blocked: the Gate2 should send 20 bottles on port 1 then take 2 seconds of switch time to switch to Port 2 and send 20 bottles and then switch again for 2 seconds) this should be repeated until my PE4 is cleared

I understand there will be couple of bottles between Gate2 and PE4 that wouldnt go out. I wouldn't worry about that right now.

I am trying to make this happen I am stuck. Let me know. Thank you. conceptpn-003.fsm

[joshua_s]

@Varun Rawal

I changed up the process flow logic so now the trigger is any items in the accumulation bed and accumulation conveyor will trigger the back and forth

13331-conceptpn-003-change.fsm

[varun_r2]

@Joshua S This gets the logic based on the accum bed. I am still trying to learn flexsim so want to confirm few things.

I understand we used - model().find("Conveyor128").subnodes.length>0 in order to understand whether conveyor 128 is empty or we still need to empty it out.

However what happens is when it is empty : the tokens still remain in the last Pull from list.

I am trying to put a photo eye as shown which when cleared, the tokens should go into normal operation. I thought to put wait for an event and use PE4 on block to trigger the switch of two ports and when it is cleared it would just be one port (Port 1) somethings not working though.

I want to learn how to do this, this would help me using photo eye in the same situations on different parallel projects. capture.jpg

[joshua_s · Accepted solution]

@Varun Rawal

The way the process works now is Gate2 is not deciding which port it will pull items from now. Items reach the 2 decision points, are stopped, and are pushed to a list. In process flow, these items are pulled off that list and then are moved to Gate 2. I have a loop happening where it tries to listen if there is anything to pull from Port 2, and if not, pull items from Port 1. There will always be a token seeming to sit at the second pull from list because there is nothing to pull from Port 2 then, and if there is nothing to pull from Port 2, then anything to pull will be from Port 1. f there is something to pull from Port 2, then the token follows a whole different path that does the switching from Port 1 to Port 2 every 2 seconds till there is nothing left in Port 2 and the accumulation bed.

So would you like the process to change so that much of the logic is triggered based on the photo eye?

[varun_r2]

Thanks for the explanation. I understand it more clearly now.

Now what happens is if there are no bottles in Port 2 (model time after 5600 seconds) (i.e nothing to pull from port 2) it would wait for the items to be sent in Port 2 until the Gate kicks back in. And the items in Port 1 will start accumulating.

What I want is if there are say even 10-15 left over bottles in Port 2, I do not want the gate 2 to switch and send those last 10-15 bottles (because if it switches it would send out specified number that is 20 and will have to wait for another 5 more bottles to come in to port 2). So what I thought is I would put a photo eye in Port 2 which would tell if I am clear I want my Port 1 running as normal i.e gate would not switch and when the PE is blocked meaning conceptpn-005.fsm more than 10-15 bottles; only then the Gate 2 would work as 1:2.

Let me know if you can find a way. I am trying to determine where I can put this in the process flow so that It would work. Thank you for your immense help.

[joshua_s]

The model you uploaded has the bottles as invisible. So you would like Port 2 to batch 20 items, then send those, and if there are less than 20, do not switch the gate to port 2, and the photo eye used to detect 20+ bottles on port 2 so that the gate will switch to port 2?

[varun_r2]

Thats correct.

Let me explain why I am planning to do this. Please find the attached image

1. First scenario: the process is running without any failures in downstream processes which means that the parts(bottles) would be produced and conveyed through the route 1 i.e Port 1 and keep going downstream

2. Now, when any downstream applications fail, the bottles would start accumulating upstream and when they accumulate and block PE1 as you can see in the model, the Gate1 would divert the bottles to take route 2 i.e port 2 (this port is the accumulation bed and which is intended to use a temporary storage buffer only).

3. After the above situation. I would have bottles on two ports 1 and 2. I need to keep my first port running and also keep pulling some bottles out of port 2 to empty it out until a specific threshold. Soon that is met, I would start using the normal operation (meaning situation number 1).

In order to decide when to stop using the Port 2 I am trying to use a photo eye as shown in the image attached. If you can see the bottles have cleared the photo eye in Port 2 . Now I just want to go via normal operation (no gate switch, keep running through port 1) . And, when any failures happen in downstream its going to accumulate again and block PE1 which would ask Gate 1 to send bottles to port 2. Soon the bottles in Port 2 block PE4 the gate 2 should start switching which would get us back to situation number 2.capture.jpg

[joshua_s]

That makes sense, can you upload your model again that you sent last time, the bottles are invisible, or upload the 3D model you are using for your bottle.

[varun_r2]

@Joshua S Please find the attached. What i did is changed the flowitem to a box with same dimensions so that you can see it.

conceptpn-006.fsm I used a sketch up file for the bottle (i do not know why it is not visible when i send it to you). Please let me know if it still gives issues. Thanks.

[joshua_s]

@Varun Rawal

Working with a photo eye is much easier and simpler

13436-conceptpn-006-1.fsm

[varun_r2]

Thats perfect.

Can i run in a normal mode also. Meaning not in batches. It still has a count, but gonna release one by one per the availability on my exit transfer4 (Conveyor40)

[varun_r2]

the PE4 logic in the decide is what I needed. It will help me out a lot. Thanks.

[joshua_s]

The batching is there just a a counter, so after 20 items from port 2 leave, then it will switch.

[varun_r2]

@Joshua S I have tried attaching animation video Ex 1 and Ex 2

If you see Gate Ex2 .The gate would send the bottles as per the availability of the downstream no matter what the batch size on both the lanes. If you see even after it switches it would send the bottles to match the downstream and then it would slow it up as per the downstream availability.

Whereas in Gate Ex1, (the logic that we really need), the gate would take bottles in size 20 store it and send as per availability. Meaning t would keep taking bottles after it switches and store it. I want a smooth flow as in Ex2.

gate-ex-1.7z

Please advise.

[joshua_s]

@Varun Rawal

Trying to understand what the final process is with the constraints of the gate. Are you wanting a continuous flow, and if so how would you have that with the time it takes to switch at the gate?