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christian.n asked Jason Lightfoot edited

Stopping and resuming Mass Flow Conveyors

Hello everyone.

I have started converting one of my packaging line models to the new MFC system in v21.0.0.

For that purpose, I am using MFCs for both conveyors and processing stations in order to completely eschew discrete flow items. The system is relying on photo eyes to determine when to stop and start conveyors and processing stations. The attached demo model has three MFCs - one generative MFC followed by the MFC representing the processor followed by a MFC which tracking loss to work as a sink.

I have two questions about this.

1) I am using a set of photo eyes and a process flow with Wait for Event activities to call object.stop() and object.resume() functions to start and stop the MFC representing the processing station. One photo eye stops the process if it becomes uncovered, and the other photo eye starts the process when enough material has accumulated. This works, but only if I put in a delay to allow the processor to have had an initial input. In the attached model, if I have the delay of more than the traversal time of the first MFC, it works. If I don't have such a delay, it does not.

2) If I wanted to keep the processing station running (clearing existing content), but without further input, how would I go about that? I tried object.input.stop() and object.input.close(), but that didn't do the trick.

Thanks in advance

Christian, NIRAS

FlexSim 21.0.0
flexsim 21.0.0mfc
1607600658696.png (83.0 KiB)
mass-flow-test.fsm (44.0 KiB)
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Jason Lightfoot answered Jason Lightfoot edited

Another workaround so you don't need a delay is to set the speed to almost zero and then set it to full speed again. Looks like a bug though. Changed model attached to set _zero speed.mass-flow-test_jl.fsm



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christian.n avatar image christian.n commented ·

@jason.lightfoot Thanks, Jason.
Was there a way to close the input of a MFC, to perform line clearance and such?

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Jason Lightfoot avatar image Jason Lightfoot ♦ christian.n commented ·

BottleStop: another quick workaround for now, add a small section instead of stopping the whole filler. To snap shorter distances than 0.2m you'll need to edit the conveyor system properties' snap threshold:

mass-flow-test-jl2_bottleStop.fsm

Model attached.

@anthony.johnson says the effect of closing the input should be possible using

object.setProperty("UpstreamOutputOrder", 0) 

Unfortunately, it's not working right now, but it should in a future release.

Update: Now working in 21.0.1.

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Jason Lightfoot avatar image Jason Lightfoot ♦ christian.n commented ·

A 'bottle stop'? I'll check. Also note I tried casting as a Conveyor before using the stop() and resume() methods and those didn't work either.

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