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Inserters: Difference between revisions

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(Extensive discussion on inserter throughput, based on experiments in 0.15.)
m (All inserters can pick up from all belts, at least in 0.15.)
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Inserters may have problems picking up items:
Inserters may have problems picking up items:


* From very fast belts, because the items are moving too quickly. ([[Inserter|basic inserters]] cannot pick up from [[express transport belt]] for example)
* From very fast belts, because the items are moving too quickly.
* From the entry or exit of an underground belt (because the time they have to pick up is shorter)
* From the entry or exit of an underground belt (because the time they have to pick up is shorter)
* From turning belts if the item is on the inside of the corner
* From turning belts if the item is on the inside of the corner

Revision as of 00:50, 22 May 2017


For the common yellow electrical inserter, see Inserter.

Inserters are devices which are used to move items over short distances. When placed, they have a fixed direction. They can move items from behind and place them in front of them. By doing this, they can move items from one transport belt to another, but also extract items from, and insert items into machines or storage devices. There are seven types of inserters, all requiring electricity to run (except the Burner Inserter, which burns fuel).

Types Of Inserters


Mechanics

Inserters will:

  • Pick up Items off the ground, off of a Transport belt, or from any object that has storage space, including chests, furnaces and assembling machines.
  • Place the item onto the ground, onto a transport belt, or into any object that has storage space.
  • Inserters can place items on all types of conveyor belts.
  • Try to pick up items from all types of belts (as of v0.12 there is no limitation anymore).
  • Inserters will run at slower speeds when starved for energy.

Inserters will not:

  • Pick up any items that can not be inserted into the connected entity.
  • Pick up items into an entity with a full inventory.
  • Place more than one item at a time onto the same ground tile.
  • Place items into a stack limited inventory, beyond the stack limit (red slots).


Inserters act differently depending on what they are moving items to/into so as not to monopolize all of the items being picked up. This allows other machines and inserters on the same transport belt to pick up a share of the items. If two inserters are picking up from the same tile, the first placed inserter has priority.

Insertion Limits

Inserters will stop inserting items into certain buildings if they already have enough of that item. For example, if a boiler has 5 or more items of fuel in it, an inserter will not insert additional fuel. When the fuel drops below 5 items, the inserter will continue to insert more fuel, up to the limit of 5 items.

This is to allow for all machines to receive their share of items. The common limits on insertion are shown in the table below.

Entity Item type Inserter limit Comment
Boilers, Burner inserters, Furnaces Fuel 5
Gun turrets Bullet Magazines 10 Since v0.8.4. Allows for 100 shots before depleting.
Assembling machines Items needed for the recipe Double the number of items needed in the recipe
Furnaces Items needed for the recipe Double the number of items needed in the recipe
Labs Science packs Double the number of items needed for one research point

An inserter that takes items from an object containing stacks of items (such as a chest) can overfill the target building due to the Inserter item stack size bonus research. Overfilling can also happen if multiple inserters are used to insert items into one building.

Inserters And Transport Belt Interaction

Transport belts have two lanes on which items can travel. Inserters only place items onto one side of the belt. Which side they place it on depends on the orientation of the inserter and the belt, as described below.

  • Inserters will always place the item on the furthest lane.
  • Inserters prefer taking items from the nearest lane. If the nearest lane is empty, the inserter will take from the far lane.
  • If a belt is in the same orientation as the inserter, the item will be placed on the right-hand lane, from the belt's perspective.
  • If the item is placed on a corner piece, it will be put on the inside of the curve, regardless of orientation.


Potential Issues

Inserters may have problems picking up items:

  • From very fast belts, because the items are moving too quickly.
  • From the entry or exit of an underground belt (because the time they have to pick up is shorter)
  • From turning belts if the item is on the inside of the corner

Inserter Item Stack Size Bonus

If an inserter moves items from inventory to inventory (for example from an assembler into a chest), or (as of v0.13) from an inventory to a belt, it is able to transport more items at once. The secret behind this is the Inserter item stack size bonus research.

Power Usage

  • Electric inserters drain energy even when they are not moving, as idle power
  • The amount of energy used is the same for every movement
  • The Burner inserter does not drain energy when idle, but uses more energy when it is active. It is quite useful for situations where the inserter does not need to move very often.


Inserter Speed

Type Rotation-speed (turns per Tick)
Extension-speed (Tiles per Tick)
Turns per Game-second
Tiles per Game-second
Game-second per full turn
Game-seconds per Tile
Ticks per full turn
Ticks per Tile
Burner Inserter 0.01
0.0214
0.6
1.284
1.667
0.833
102
76
Basic inserter 0.014
0.03
0.84
1.8
1.191
0.56
72
54
Long handed inserter 0.02
0.0457
1.2
2.742
0.833
0.416
52
36
Fast inserter 0.04
0.07
2.4
4.2
0.417
0.238
26
24
Stack inserter 0.04
0.07
2.4
4.2
0.417
0.238
26
24
Stack filter inserter.png
Stack filter inserter
0.04
0.07
2.4
4.2
0.417
0.238
26
24

Rotation Speed

Convention: 2π rad = 100% of a circle rotation = 1 turn (or one full rotation).

Note: an Inserter doesn't always need to make full turns. When grabbing from a transport belt, it is slightly faster when grabbing items from the closest lane.

Extension Speed

The extension-speed is normally not visible (only when compared to other inserters), but there are measurable speed differences when taking - for example - from the near or the far side of a belt. Also Some mods can alter the pickup and drop locations of inserters, making this stat more relevant.

Inserter Throughput

The following is based on experimental data gathered in version 0.15.

Inserter throughput between chests and other stacks is a simple function of stack size and arm speed:

n = Stack size

t_arm = Time to move the arm back and forth

Time per item = t_arm / n

Throughput (items/sec) = 1 / Time per item = n / t_arm

When moving items to or from belts, the time to pick up or put down items also becomes a factor:

t_item = Time to pick up or put down or an item

t_c = Time to complete an arm cycle = t_arm + n*t_item

Time per item = t_c / n = t_item + t_arm / n

Throughput (items/sec) = 1 / (t_item + t_arm / n)

Due to some simulation quirk, inserters are noticeably slower when moving items from south to north. The effect is between 1% and 4% and it tends to be bigger for larger stack sizes. All the measurements below are based on south-to-north movement, to avoid overestimating throughput.

Chest to chest

These are measurements chest-to-chest in south-to-north direction.

Type Arm cycles per second Percent
faster not
south-to-north
Items/second at capacity bonus level (stack size)
No capacity bonus Capacity bonus 2 Capacity bonus 7
Burner inserter 0.59 1.0% 0.59 (1) 1.18 (2) 1.77 (3)
Basic inserter 0.83 1.4% 0.83 (1) 1.66 (2) 2.49 (3)
Long handed inserter 1.14 1.9% 1.14 (1) 2.29 (2) 3.43 (3)
Fast inserter
Filter inserter
2.24 3.7% 2.24 (1) 4.49 (2) 6.73 (3)
Stack inserter
Stack filter inserter.png
Stack filter inserter
2.24 3.7% 4.49 (2) 8.98 (4) 26.93 (12)

Chest to belt

Besides the inserter direction as noted above, the throughput going from chest to belt depends on how full the belt is and how the items are spaced, i.e. if spaces are large enough to fill with items. Underground entrances and exits also makes it easier for the inserter to put down an item.

In these measurements inserters move items south-to-north onto an empty perpendicular belt. Values are given for the stack sizes at three different capacity bonus levels.

Type Percent
faster not
south-to-north
Items/second at capacity bonus level (stack size)
No capacity bonus Capacity bonus 2 Capacity bonus 7
File:Basic-transport-belt.png File:Fast-transport-belt.png File:Express-transport-belt.png File:Basic-transport-belt.png File:Fast-transport-belt.png File:Express-transport-belt.png File:Basic-transport-belt.png File:Fast-transport-belt.png File:Express-transport-belt.png
Burner inserter 0.9% 0.58 0.58 0.58 (1) 1.10 1.13 1.14 (2) 1.53 1.62 1.67 (3)
Basic inserter 1.3% 0.82 0.82 0.82 (1) 1.51 1.57 1.59 (2) 2.04 2.22 2.30 (3)
Long handed inserter 1.7% 1.14 1.14 1.14 (1) 2.01 2.12 2.16 (2) 2.63 2.93 3.08 (3)
Fast inserter
Filter inserter
3.0% 2.23 2.23 2.23 (1) 3.55 3.90 4.03 (2) 4.23 5.05 5.51 (3)
Stack inserter
Stack filter inserter.png
Stack filter inserter
1.7% 3.55 3.90 4.03 (2) 4.68 6.08 6.75 (4) 6.09 9.86 12.49 (12)

To calculate the throughput for Stack inserter and Stack filter inserter at any capacity level, you can use these linearly fitted factors with the belt/chest throughput formula above:

Type Transport belt Fast transport belt Express transport belt
t_item t_arm t_item t_arm t_item t_arm
Stack inserter
Stack filter inserter.png
Stack filter inserter
0.137 0.312 0.070 0.378 0.047 0.402

See the source spreadsheet for the corresponding factors for the other inserter types. Their errors are generally well below 1%.

Belt to chest

When picking items from a belt, many more factors come into play besides those mentioned above (inserter direction and belt fullness):

  • How fast the items move (i.e. if they are queued up on the belt or move at belt speed).
  • Whether the belt is perpendicular to the inserter or approaches it head on.
  • Whether items are on the near or far lane of a perpendicular belt.
  • Whether the belt turns or not, and whether the items are in the inner or outer side of the bend.
  • If the belt is an underground entrance or exit. This shortens the time items are visible to the inserter for pickup.
  • All sorts of intricate timing factors between the inserter and the items on the belt, since the game simulates the arm homing in on every item.

The test setup used below is with a south-to-north inserter taking items from a perpendicular belt with items on the far lane only. The belt is fully compressed and timings are both for items that move at full speed and queued up as much as possible. Values are given for the stack sizes at three different capacity bonus levels.

Type Percent
faster not
south-to-north
Items/second at capacity bonus level (stack size)
No capacity bonus Capacity bonus 2 Capacity bonus 7
Items at
belt speed
Items
queued
up
Items at
belt speed
Items
queued
up
Items at
belt speed
Items
queued
up
File:Basic-transport-belt.png File:Fast-transport-belt.png File:Express-transport-belt.png File:Basic-transport-belt.png File:Fast-transport-belt.png File:Express-transport-belt.png File:Basic-transport-belt.png File:Fast-transport-belt.png File:Express-transport-belt.png
Burner inserter 0.9% 0.56 0.53 0.50 0.64 (1) 1.03 1.03 0.98 1.17 (2) 1.44 1.54 1.43 1.70 (3)
Basic inserter 1.3% 0.82 0.74 0.77 0.88 (1) 1.57 1.49 1.48 1.60 (2) 2.01 2.11 2.01 2.38 (3)
Long handed inserter 1.8% 1.11 1.11 1.05 1.20 (1) 2.11 2.06 2.01 2.27 (2) 3.01 2.97 3.01 3.28 (3)
Fast inserter
Filter inserter
3.3% 2.15 2.22 2.07 2.31 (1) 4.01 3.82 3.82 4.14 (2) 5.47 5.02 5.47 6.01 (3)
Stack inserter
Stack filter inserter.png
Stack filter inserter
1.9% 4.01 3.82 3.82 4.14 (2) 6.17 6.18 6.43 6.69 (4) 6.67 10.03 12.09 13.40 (12)

Since there are many more factors involved, these measurements exhibit a more complex pattern than chest-to-belt.

  • Boldface cells show for which belt each inserter has the best throughput on each bonus level when items move at belt speed. Higher speed belts mean that inserters have to work harder to catch the fast moving items. The effect is most noticeable for slower inserters and smaller stack sizes.
  • When items are queued up the belt type hardly matters, so there is only a single column for that. There is however one exception - see (*) below.

Here are linearly fitted factors to get the Stack inserter and Stack filter inserter throughput at any capacity level, by using the belt/chest throughput formula above:

Type Transport belt Fast transport belt Express transport belt
t_item t_arm t_item t_arm t_item t_arm
Stack inserter
Stack filter inserter.png
Stack filter inserter
0.054 (*) 0.410 (*) 0.065 0.386 0.045 0.437

*) A stack inserter combined with a basic transport belt gets capped by the belt speed at stack sizes above 4, so these figures are only accurate up to size 4. More than that and the throughput is fixed at 6.67 items per second.

See Also

Special behavior