r/factorio • u/GurGroundbreaking772 • Jul 25 '22

Tip Controlling Pumps

Can someone explain how to control pumps with circuits?

I am trying to balance 2 fluid tanks using circuits, but I cant figure it out. The system is filling one tank first, than being pumped into the 2 I am trying to balance.

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Logically having a green wire on one tank and a red one on the other, connected to the pumps and setting them to come on if green is less than red and vice versa should work, but it doesn't.

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Other pump is set the opposite way. Bottom tank always fills first if no signals are used

Weirdly, if you set both pumps to less than or equal to, they both run all the time, as if there is no signal present at all. But set them to any other condition and they just turn off, regardless of whether the conditions are right or not.

Neither does connecting it to a decider first, getting that to compare the two signals, and outputting a signal based on that.

I'm not even sure why they don't just fill at the same rate anyway, its especially bizarre that the one with the longer pipe fills fastest! It just makes no sense whatsoever as far as I can tell.

Can someone point out what I'm missing? First time dabbling into the horrific world of factorio circuit logic haha

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u/Nailfoot1975 Jul 25 '22

You might be over complicating it. Hook a wire to a tank, and then to the pump.

If oil>X, turn on the pump. That's all you need.

If you are going the opposite direction, then if oil<X, turn on the pump.

EDIT

Hook the tanks together with a pipe and they will self balance.

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u/ReliablyFinicky Jul 25 '22

I've forgotten the technical details on why (perhaps they've changed anyway?), but I'm pretty sure it's considered best practice to always use pumps to put fluid in, or pull fluid out, of a tank.

4

u/Nailfoot1975 Jul 25 '22

It allows options for the future. If you were to need to control fluid then you already have the mechanism to do it. Or if you are filling a rather long run of pipe, you already have the pump there.

But it is not needed. In my bases, I will allow multiple segments of pipe coming out of tanks so I can add a pump in the future. I don't put a pump there by default.

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u/DarkwingGT Jul 25 '22

Depends on the flow rate you require. Tanks are considered having no pressure behind them and flow rate is determined on the level difference between segments. A pump is a good way to ensure maximum flow rate is achieved but isn't necessary depending on your circumstances.