"Dry run" mode for Assembling Machines via "No Item" signal

[terradus]

I suggest allowing Assembling Machines to accept the "No Item" signal (the internal "Null" item) as a valid recipe via the Circuit Network. This would enable a "test mode" or "dry run" for assemblers without requiring actual ingredients or producing outputs.

04-20-2026, 15-10-50.png (105.03 KiB) Viewed 263 times

Details:
Trigger: When "Set Recipe" is enabled and the assembler receives a "No Item" signal.
Behavior: The machine enters a working state and consumes electricity as if it were crafting. No resources are consumed, and no items are produced.
Circuit Interaction: The machine should still output signals like "Read working status" and "Read recipe finished."
Use Cases & Benefits:
Currently, it is difficult to accurately count the total number of functional assemblers in a large-scale build using only the Circuit Network, as machines are often idle due to resource bottlenecks or full outputs.
Implementing this "dry run" would allow for:
Fault Detection: Automatically detecting if a machine has been destroyed or disconnected (e.g., "Expected 30 active signals, but only receiving 29").
Scalability Management: Checking if a new production block is correctly wired before providing it with expensive resources.
Throughput Analysis: Measuring theoretical maximum power consumption or timing logic cycles without wasting materials.
This feature would significantly enhance vanilla automation for megabases and complex Space Age logistics without the need for external mods.

p.s. also Fully Automated Production Analysis: This allows for the creation of universal circuit controllers that can be connected to any unknown sub-factory to automatically calculate its potential capacity and identify idle machines without any manual oversight or external mods.

[terradus]

+Precision Diagnostics & Recovery:
With a standardized crafting time of 1 second, the circuit network can automatically compare active signals against the expected count of connected assemblers. This allows the system to detect desynchronization or reduced working speeds caused by power grid failures (e.g., partial blackouts where one section is powered on 100% and another is on 70%). This is especially critical for automatically verifying factory integrity after biter attacks, ensuring all machines are present and operating at 100% capacity without manual inspection.

And finally — it would just be cool!

[boskid]

I am not interested in this. It feels super complex for doing simplest things, if you want to detect if any assembler was destroyed you can just run a wire that goes in series over all assemblers, have a constant combinator on one end and detect if the signal is present on the other end. A "dry run" recipe would not be an accurate representative since it would require having some value of the recipe crafting time and it could happen to be different than the recipe you want to use so it would be pulsing for recipe completition at a wrong pace. Also such recipe would have to be a special one that has all recipe categories to be guaranteed craftable in each crafter, which only adds complexity. If instead this was requested as having a regular recipe but having it crafted without ingredients then this feature would add a lot of extra weird edge cases for game to handle (not returning ingredients due to recipe being crafted in a dry run, not producing items when giving products) and for mods to handle (edge case of a crafting machine having an increasing counter of recipes finished while machine was not producing). It does not even add anything interesting to the gameplay.