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Nurul Shuhaida KS avatar image
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Nurul Shuhaida KS asked Logan Gold answered

How to set some equipment on standby?

Let say I have 3 pumps in the plant, and I want to set one as standby, how should I do that?

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Logan Gold avatar image Logan Gold ♦♦ commented ·

@Nurul Shuhaida KS, Could you give us some more information about how a pump is supposed to function during standby versus how it functions during normal use?

Can it still accept product during standby, but it's limited on how much product it can handle? In that case, you might use a Processor and set its capacity to be smaller.

Is it considered down for a certain amount of time during standby? Then you might look at the MTBF/MTTR functionality.

Is it only supposed to be used if the other two pumps are too busy? You could make sure the first two pumps receive product first and the third one only receives product when the first two are busy. Or you could prevent product from getting to the third pump by closing that pumps input ports, then open the input ports only when certain conditions are met.

Any information you can give us to how the pumps work compared to different FlexSim objects would be helpful. And a sample model that shows how any part of the process should work would be even more helpful.

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Nurul Shuhaida KS avatar image Nurul Shuhaida KS Logan Gold ♦♦ commented ·

The pump on standby will not be receiving any product while the other two pumps are running. The pump on standby only receive product when one of the pump is not running due to preventive maintenance activity or repair due to failure. In this case, the pumps are running parallel at 2 out 3 requirement. The uptime and downtime of the pumps are determine by the MTBF and MTTR.

and in this case I would to do the availability analysis of the pumps system.

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tannerp avatar image tannerp Nurul Shuhaida KS commented ·

I'm hoping to build you an example model of how this could work, but I noticed you didn't specify which version of FlexSim you are using. Please let us know what version you have and in the meantime I'll just work on a general conceptual model.

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1 Answer

Logan Gold avatar image
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Logan Gold answered

I am attaching a model (standby-example.fsm) to give an example of how you could do this.

I have three Processors that represent the pumps. All three are connected to a Queue, but it doesn't matter where the flowitems are coming from as far as the logic goes. The top two Processors are also in a Group called MainPumps that is referenced in the Process Flow.

In the Process Flow, I have two sections that represent the different pumps in the 3D. The left section represents the standby pump, and the right section represents when the two main pumps go down because of the MTBF/MTTR. I have included a description with both sections to describe how they each work. Both sections work together by using a List to determine when at least one of the main pumps is down so the standby pump knows when to work and when to be on standby.


standby-example.fsm (40.5 KiB)
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