Circuit Networks

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Circuit networks are created by connecting machines using red or green circuit wires. The wires carry virtual signals between machines instantly. Every machine in a network can read every signal, and some machines can publish signals to the network. Machines can also be given enabled conditions, which make them run only when a particular signal meets a particular threshold.

Combinators let you manipulate signals in more sophisticated ways. Some players have built entire computers out of them. That depth can make circuit networks seem daunting, but most practical uses only need simple networks without any combinators at all.

Factorio Access supports all base game circuit network features. For the full reference on keybinds and advanced combinator controls, see the FA docs page on circuit networks.

To open the circuit network menu of a connected building, select it with the cursor and press N.

Wire connections

Pick up a red, green, or copper wire with ALT + R, ALT + G, or ALT + C. With a wire in hand, press LEFT BRACKET on each entity you want to connect — the wire chains from entity to entity in sequence. Press Q once to reset the chain (without emptying your hand), or Q twice to empty your hand entirely. To disconnect two entities, connect them a second time. To drop all wires on an entity, press ALT + N.

Combinators and power switches have two connection sides. Use M to connect to the left side or input, and . to connect to the right side or output.

Two machines connected by a wire form a circuit network. Connecting more machines with the same wire color extends the same network. A different wire color starts a separate network. A machine can belong to a red and a green network simultaneously and will read from and publish to both.

Wire reach between non-pole structures is about 10 tiles. Electric poles extend reach up to their normal wire range.

Read behaviours

Machines like chests and storage tanks can publish their contents to the network. In hold mode (the default), a signal is emitted for every item the machine contains, with the value equal to the quantity. Multiple machines holding the same item type add their quantities together on the network.

Inserters and belts can alternatively be read in pulse mode, which sends a one-tick signal for each item passing through. This is useful for triggering one-shot actions.

Enabled conditions

Inserters, belts, pumps, and power switches can be set to operate only while an enabled condition is true. The condition has three parts: a decision signal, a condition operator (such as greater than or equal to), and a reference signal or constant number. The machine runs while the condition holds and stops when it does not.

Special signals

Virtual signals are not tied to any item or fluid — they represent abstract values used in logic. A special subset are the wildcard signals:

• Everything — used in conditions; true if every non-zero signal in the network meets the condition.
• Anything — used in conditions; true if any signal in the network meets the condition.
• Each — used in arithmetic combinators; applies the operation to every non-zero input signal individually.

Combinators

Constant combinators inject signals into the network manually. Add signals using the signal selector and toggle the combinator on or off with LEFT BRACKET.

Decider and arithmetic combinators let you compute new signals from existing ones. For controls and full details, see the FA docs page on circuit networks.

Use cases

• Smart oil cracking. Storage tanks are read and fluid pumps have enabled conditions so that heavy oil and light oil are cracked only when needed.
• Efficient nuclear plants. Steam storage is read so reactors are refuelled only when steam runs low, avoiding nuclear fuel waste.
• Smart output chests. Output inserters read chest contents and stop when a threshold is reached, preventing overproduction without locking chest slots.

More ideas are in the official wiki's circuit network cookbook. Note that many entries there rely on images.

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See also:

• Fluid Handling Systems
• Inserters

External links:

• Official Factorio Wiki: Circuit network
• FA Docs: circuit-network