Jump to content

Recommended Posts

Hi - 

I have a vehicle that moves through several servers, one of which is 'LunchBreak;' however, when running the model, the vehicle parks at LunchBreak and the people do not get off and nothing more happens the entire run. Thoughts as to why it gets stuck here?

image.thumb.png.25a0ebebfd828a926d9e6b1c4f8a3897.png

image.png.415674d8361cebd4ed4403bc5593faba.png

Link to comment
Share on other sites

Hi M_A,

It is difficult to determine what could be causing this without seeing the model. Here are a few things I suggest investigating:

  1. Ensure that your model run time is set run long enough for all of your entities to flow through your system. To test this, I would set your model run time to Infinity, and create 1 set of 35 employees. Then see how long it take for the model to cycle through all entities. You may be able to use some Animation at this step to see where the entities are getting stuck.
  2. Along with #1, I suggest turning on the Model Trace and reviewing the steps taken for each of your employees and the bus.
  3. If you are using an unbounded random distribution (for example a normal distribution) for any of your processing times, then the result of that distribution could be something very large. You should be able to see if that is the case within your Model Trace review as well.
  4. Lastly, make sure all of your Transfer Nodes are set to route By Sequence and require the bus for transport.

Hope this helps.

Thanks,

Ryan

Link to comment
Share on other sites

Hi Ryan,

-The model gets stuck at about an 1 hour into it. Can't get it past the vehicle going back to the 'Bldg,' as seen when I track the vehicle.

-The distributions are all random triangular with set parameters in the Sequence1 Table.

The idea was that the 35 people/Entities would arrive at the Bldg Source and as Entities the JobsTable would assign a random triangular number of workers to a job and then start ferrying them per the sequence in the Sequence1 Table from the Key Column from the Bldg. The vehicle can carry 6 people but it seems to only carry 4 at a time.  Also, the ferrying is completed at about an hour and the vehicle just stops at the Bldg with 4 passengers. Instead, it needs to continue ferrying by having the entities 'call' the vehicle to their location to continue the route sequence, through LunchBreak, and then get eliminated at the EndOfShift node.

11May.v2.spfx

Link to comment
Share on other sites

Hi M_A,

The sequences in your table are never assigned to the entities before or as they are created. Assigned the sequences by selecting the entity instances in the Facility view, and set the Initial Sequence property under Routing Logic to 'Sequence1'. Also, the Entity Destination Type property on all of your Transfer Nodes, including the outputs nodes of all Servers, must be set to 'By Sequence' in order for the entities to follow the sequence appropriately.

Here are a few other things I noticed while looking over the model:

  • All of your Servers only have the capacity to process 1 entity at a time, so for your case only one employee can work in that area at one time. As soon as each employee is done working they will request a pick up 1 at a time. May not be what you are looking for here. 
  • The processing times at the Servers aren't linked to the table. You can link them by setting them to 'Sequence1.ProcessingTime'. Be sure to set the appropriate units in the column properties of ProcessTimes.
  • It is hard to see the network that is available for the Vehicle, so one more thing to check is that the Vehicle has all of the needed paths to pick up and drop off the entities.

Thanks,

Ryan

Link to comment
Share on other sites

Hi Ryan,

Thank you for the corrections.  As always, spot-on advice, that is very appreciated. I do have a few follow up questions.

- Do I set the Initial Sequence property to 'Sequence1' or do I need to tell it the row too? 'Sequence1.Sequence'? Sequence 1 is working, but just wondering.

- In the SimBit, Entity Follows Sequence With Relational Tables, there are three types of Entities that all flow through the same source with the Source Property, Table Row Referencing, pulling from the JobTable with the Row Number 'JobTable.ProductMix.RandomRow.' For my model, I have two different entities and the source Bldg is supposed to pull BOTH entities with the Table Row Referencing, "JobsTable" with Row Number: "JobsTable.NumberWorkers.RandomRow." But when the model is run, only one entity is ever used. The Table has an ExpressionProperty of Random.Triangular(3,6,9). Is that the problem? The SimBit's table was an actual number. I tried replacing the Expressions with actual numbers and the Entity switched to use the other one but I am still not able to get half the 34 to be one Entity and the other half to be the other Entity.

- How do I get the Vehicle to carry its max capacity? The capacity is set to 6, and it only carries up to 4 entities around at any time. This is incorrect, as the Entities are supposed to be grouped into work teams of Random.Triangular(3,6,9) for their initial Source output move. Afterwards they can be individuals or work teams. The Bldg has the Entity Type defined as the JobsTable.Specialty so it should pull from one or the other (like the below mentioned SimBit), and the with Entities Per Arrival Set at 35; and the Entities themselves are set to a population maximum of 17 each and I get a Runtime error of maximum number exceeds limit for the entities. Why doesn't it hit the limit and then pull from the other Entity? 

- I'm confused about the network you mentioned above. I thought the nodes had to be linked directly (output to input node). So the busy nodes have a lot of paths radiating out from them and it makes it a little messy. Is there a cleaner way to show the routing?

Thank you,

Link to comment
Share on other sites

Hi M_A,

Just setting the Sequence property to 'Sequence1' should be enough since you set up relational tables.

Because you have Maximum Arrivals set to '1', it is going to produce 1 entity type. I would switch your Maximum Arrivals to '35' and number of entities per arrival to '1'. You will also need to set your interarrival time to '0', so all 35 show up at the same time. It might be best to use a second Source object to create your second shift.

I would increase the length of the Ride Station Queue in order to see all 6 passengers boarding the Vehicle.

I think the network is fine, but hard to debug. Be sure all travel destinations for the Vehicle are possible.

Thanks,

Ryan

 

Link to comment
Share on other sites

×
×
  • Create New...