[0.16.51] Train waiting for "Circuit" from "Read train con

[mhcmega]

[0.16.51] Train waiting for "Circuit" condition, calculated from "Read train content", requires additional wait condition to work properly
Note: Subject length limit makes it hard to make meaningful title

I wanted train to depart after any of its two products: green boards or copper plates depleted.

So I used option "Read train content" on Station and calculated in Arithmetic calculator:

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A = copper_plates * green_boards

And set train "Wait until" to

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Circuit: A < 1

This does not work, train stops and immediately starts.
I additionally added 1 second wait, then train stopped and waited until any of two products depleted.
IMO train exports its content data and reads circuit condition in the same tick. But signal "A", based on content read from train, is updated in next tick. So train departures basing on outdated signal.

Expected solution:
Trains stopped on station that uses "Read train contents", that also uses "Wait until: Circuit", should wait long enough before reading signal that signals state can be updated.
Alternatively, all trains wait at least one tick after stop, before deciding about departure.

Work around:
Add "AND 1 seconds passed" to "Wait until"

[boskid]

Not a Bug

Circuit network has finite, non zero delay because it is tick-based. You may get content from train in one tick, but at the same time, wait condition is already meet because signal A is still equal to 0 (it will be available in next tick as there is one logic component between). Additional wait time prevents condition beeing meet in first tick after train arrival.

Fixing this as you want would require developers to introduce arbitrary delay to trains, which may be appropriate for you but not for more complicated logics requiring more ticks to compute.

btw, your condition using multiplication looks like workaround to simple OR condition - you should be able to set condition right in train schedule: "copper = 0" OR "gc = 0" (use "and/or" button in train schedule options)

[mhcmega]

your condition using multiplication looks like workaround to simple OR condition

I knew there should be simple solution... Thank You!

Fixing this as you want would require developers

This can be booth FAD (Functions As Designed), Won'tFix or SimpleFix, let's developers decide.
E.g if architecture is:

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tick_start
    Train_stops
    Train_decide_of _departure
    Make_circut_logc
tick_end

then fix is simple changing to

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tick_start
    Train_stops
    Make_circut_logc
    Train_decide_of _departure
tick_end

As we have no idea what is architecture inside, fix can simple, can be hard, or maybe FAD

[DaleStan]

You skipped a tick in there:

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tick 1 start
    Train stops
    All devices read network (Combinator reads nothing)
    All devices write network (Combinator writes nothing, stop writes train contents)
    Train decides on departure, based on "A=0" signal
tick 1 end
tick 2 start
    All devices read network (Combinator reads train contents)
    All devices write network (Combinator writes signal A, stop again writes train contents)
    Train decides on departure, based on "A=BIGNUM" signal
tick 2 end

If you switch the read and write order, you get the same effect:

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tick 0 start
    All devices write network (No train present; train stop writes nothing.)
    All devices read network (combinator reads nothing)
tick 0 end
tick 1 start
    Train stops
    All devices write network (Combinator, having read nothing, writes nothing; stop writes train contents)
    All devices read network (Combinator reads train contents)
    Train decides on departure, based on "A=0" signal
tick 1 end
tick 2 start
    All devices write network (Combinator writes signal A, stop again writes train contents)
    All devices read network
    Train decides on departure, based on "A=BIGNUM" signal
tick 2 end

The output of any combinator is always based on the previous tick's input. This isn't helpful in this case, but it prevents infinite loops waiting for a circuit network to stabilize and it allows clocks and delay circuits.

Infinite loop: Connect the output of a combinator to its input. Set the combinator to Each+1=>Each. What values should be observed on the network?
Clock: What that Each+1=>Each combinator actually does (roughly).
Delay: Daisy-chain three Each+0=>Each combinators between an input and an output for a 1/20 second delay between an event and its reaction.

[mhcmega]

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    All devices write network (Combinator, having read nothing, writes nothing; stop writes train contents)
    All devices read network (Combinator reads train contents)

Given combinator order is reversed for me. I would rather expect ReadAll_Input->Caclulate->WrietAllOutput