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Troubles in the triggering tokens and query order.

Hello, I am trying to model an industrial replenishement process that is the following: (FlexSim 19.0.0)

Totes on "Rack15" are filled in combiner2 and sent on "Rack19" and "Rack31". At the begining there is no query for the totes replenishement. so we use "Pull from List0" activity. when the totes on "Rack19" and "Rack31" are becoming empty, they are sent back on the "Rack15" for replenishement. this time totes are selected according to the query "ORDER BY SC ASC". this time we use "Pull from List OPMP" ("Pull from List0" and "Pull from List OPMP" are just used for cases separation as required by the industrail process). I put "Acquire OPMP" activity before "Pull from List OPMP" in order to apply the mentionned query. But, I encouter two problems:

1- tokens are pulled from "Acquire OPMP" activity according to their arrival order, they don't correspond to the selected tote (see figure 1 and figure 2; this problem starts from the case 3 in figure 2 where the "itemstype" corresponding to the selected tote is 1 while this tote was filled by boxes of type 3 that corresponds to the third token "SItemsType" label value).

2- the query is not correctely applied for all totes:

- At 302.28 minutes, the tote having the "SC" value equal to 367.15 is selected while there is a tote on the "rack15" which has a lowest "SC" value (equal to 273.47). (Figure 3).

- At 320.98 minutes, the tote having the "SC" value equal to 377.25 is selected, then the tote having the "SC" value equal to 387.56 is selected while there is a tote on the "rack15" which has a lowest "SC" value (equal to 275.74).

- At 342.93 minutes, the tote having the "SC" value equal to 397.66 is selected while there is a tote on the "rack15" which has a lowest "SC" value (equal to 276.89).

- At 355.00 minutes, the tote having the "SC" value equal to 407.65 is selected while there is a tote on the "rack15" which has a lowest "SC" value (equal to 278.02).

Please help me to fix this.

Regards.

trying1.fsm

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FlexSim 19.0.9
process flowqueryflexsim 19.0.9
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1 Answer

tannerp avatar image
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tannerp answered sara S2 commented

@sara S2,

I took a look at your model and found a couple things that need to be addressed:

1) The Acquire OPMP activity is assigning a resource to token.resource. Then, further along in the Process Flow, you're assigning a new token.resource without releasing the first one. These need to be assigned to different labels if you're going to acquire more than one resource at a time. For example, assign one to token.OPMP and the other to token.resource.

2) The "CUDB" table does show that there are items with an SC value of 302.28 minutes, but the item list from which you are pulling does not have those items. This discrepancy is shown in the image below. You need to verify that all the items in the "CUDB" table are being pushed to the list if you want to pull from that pool. Otherwise, the "ORDER BY SC ASC" query is working correctly.

If you fix these things, I think your model will run closer to how you want.


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tannerp avatar image tannerp commented ·

We resolved this through email. The token needed to acquire the label of its "EmptyCUTotes" that corresponded with "SItemsType". The model attached demonstrates the fix with the Assign Labels activity after the Pull from List OPMP activity.

trying1-2-2_4.fsm

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trying1-2-2-4.fsm (123.0 KiB)
sara S2 avatar image sara S2 tannerp commented ·

@tanner.p, thank you again for your help. I really appreciate it.

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sara S2 avatar image sara S2 commented ·

@tanner.p, thank you for your reply.

Concerning the point (1), I checked your remark but I find that this is working correctly for the "Acquire" activity below "Pull from List0" even if it has also 'token.resource' which is the same label as the used in the other "Acquire" activity below "Pull from List1". This is not presenting any problem as we can see during simulation, so I think it’s the same case for “Acquire OPMP”. Concerning this point I found that the problem is in the puller of "Pull from List OPMP"; it must correspond to the token that is related to the pulled item (which has the smallest SC) not the entering token. Well I am trying to do this using "Object From Label Array" option (FIG0).

Concerning the point (2), all the placed totes on the “rack15” are pushed to this list (EmptyCUtotes). The problem is: the attributed SC value in the list doesn't correspond to the one in the table "CUDB" which I find very strange! I added column 9 in this table where I set constant values and attribute them to the pushed items in the list. The result is that those constant values are attributed correctly in the list as they are in the table (FIG 1). I really couldn’t find the reason why SC values are not attributed correctly.

trying1.fsm

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tannerp avatar image tannerp sara S2 commented ·

As long as it's working for you, then I guess my first point of concern is okay.

The second point can probably be explained by the way the list was set up. You have an expression field on the list, but the "Dynamic" box was not checked. This means that the SC value will remain whatever it was when the item was first pushed to the list. If you check the box, it constantly updates and keeps closer to the values in the "CUDB" table. Hope this makes sense.

trying1 (2)_2.fsm

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sara S2 avatar image sara S2 tannerp commented ·

@tanner.p, thank you so much for your help. I really appreciate it.

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