Smart inserter
More advanced electric inserter. In most cases, the smart inserter will be used to stop production of an item after a certain condition is met (e.g. enough items), when configured as output on an assembly.
Usage
Works at the same speed as a fast inserter. It needs to be configured to work. Configuration is done by opening the inserter interface (right mouse). You will see something like this:
The smart inserter interface has two parts: the "filter" and the "condition".
Filter part
If used (you are not forced to use the filter, it works also by using the condition part only!), the smart inserter moves only items which are in this filter (up to five items can be filtered).
It takes then only "filtered" items from a belt or other stacks (chests, assemblies, etc.). For example, if a belt contains iron and copper plates, and filter is set to iron plate, the inserter will take only iron plates, and don't touches copper plates.
Condition part
This switches the smart inserter on/off. It will work only if all set conditions are true, please refer to the Circuit network to see, how this can be used! Condition could be based on red/green circuit (the first two lines, but you need to connect red/green wire to the inserter first!) or logistic network (the last line, but you need a Roboport and the inserter must be inside of the logistic area). Typical use is to limit input/output of assembly machine: if the circuit and/or logistic network contains < X items of this type then load the assembly machine. As soon as X items are in logistic network, assembly machine is not loaded any more. Usually it's easier to limit output, so items are not removed from assembly machine and when internal storage of the assembler is full it will stop producing.
There are some examples in the forum, which will show you some of the common and not so common usages.
Using both
Finally you can use both, filter and condition, so it will only move items of one type if there are less/more than X items of that type in the logistic network (or wires).
Not working by default
This needs to be connected to the Circuit network or have a filter or condition set, otherwise it won't work!
When connected to the circuit network, it begins to work immediately, because the "no condition" is set. Set one or more conditions, and the inserter will follow the instructions.