[MCPE-12848] Comparators measuring a container take redstone 2 ticks to change their state instead of 1 Created: 30/Jan/16  Updated: 02/Dec/18  Resolved: 19/Jul/17

Status: Resolved
Project: Minecraft (Bedrock codebase)
Component/s: None
Affects Version/s: 0.14.0 Beta 2, 0.14.0 Beta 3, 0.14.2, 0.14.3, 0.15.0, 0.15.2, 0.15.6, 0.15.90.7, 0.15.9, 0.16.1, 0.16.2
Fix Version/s: None

Type: Bug
Reporter: skribe
Resolution: Works As Intended Votes: 11
Labels: redstone, redstone-comparator, redstone-timing

Attachments: JPEG File 12848-2.jpg     PNG File 2016-01-30 04.05.27.png     PNG File comparator-delays-2-ticks.png     JPEG File comparator-is-the-culprit-not-hopper.jpg    
Issue Links:
Duplicate
is duplicated by MCPE-13108 Redstone pulses from repeaters last t... Resolved
Relates
relates to MCPE-15793 Redstone components don't apply the c... Reopened
relates to MCPE-12796 Comparator Output Length too Short Resolved
relates to MCPE-15607 Pistons take 3 redstone ticks to exte... Resolved
Confirmation Status: Confirmed
Platform: Tablet - Android - Samsung Galaxy Tab 4 Nook
CHK:
ADO: 32132

 Description   

Comparators send their signal too slowly when activated. This causes a problem with unloaders because the powered rail doesn't deactivate in time to stop the minecart chest over the hopper. Usually the minecart bounces off the block and returns back along the track. The hopper is only has time to disgorge one item from the cart per run.

I've tried a couple of designs and both have the same issue.



 Comments   
Comment by Scott mc [ 02/Dec/18 ]

Quick list of the possible problems.

Power rails are reativating too quickly.

Items being taken from a minecart/hopper to another hopper are leaving the second hopper too quickly.

https://youtu.be/gr4tlA9-430

https://youtu.be/t-cWqvP8rw0

These two designs no longer work in xb360.

The mine cart drops one item and is sent back down the rail. 

 

Comment by Helen Zbihlyj [ 19/Jul/17 ]

Devs reported back that this works as intended.
Explanation:
1 tick for updating the torch.
1 tick for updating the hoppers. (arguably this could take a tick longer)
1 tick for updating the comparator.

Comment by Zeb [ 31/Mar/17 ]

This may just be a duplicate of MCPE-15793... it's hard to tell. When 15793 is fixed, we'll know for sure.

Comment by [MCPE Mod] Auldrick [ 16/Jan/17 ]

Appears to be fixed in 1.0 (Windows 10 at least).

Comment by PHO [ 16/Dec/16 ]


OH WHAT THE

...so this is very similar to MCPE-17208 / MCPE-17274...

Comment by [Mojang] Tomas Alaeus [ 16/Dec/16 ]

We don't know what exactly is incorrect and in what way it is incorrect. PHO, in the last image you posted, you will get another result if you put a repeater between the lever and the rest of the machine. (yes, that is another bug which I think is already reported) However, it looks to me that it's the dispenser that's too slow...

Comment by PHO [ 30/Sep/16 ]


The screenshot shown above proves that it's comparators that are doing the wrong thing, not hoppers.

There is a single item in the dropper. Push the button to activate a dropper that is measured by a comparator. The dropper pushes the item into the hopper after 2 ticks (as expected). The comparator deactivates after 2 ticks (unexpectedly) instead of 1 tick.

Comment by [Mojang] Adrian Östergård [ 20/Sep/16 ]

This bug has been reported to our internal bug tracker for further testing and a fix. It is scheduled to be fixed in one of the future updates (no specific date can be provided).

Comment by Zeb [ 27/Aug/16 ]

Confirmed for 0.15.6. (Tested on Windows 10.)

Comment by Lloyd Lewis [ 26/Aug/16 ]

I am trying to build an item sorting system and the slow reaction of the comparator is causing the items to go past the filter and wind up in the junk chest.

I am using a standard sorting construct with overflow protection. Items come up an item elevator into a hopper line.

Comment by PHO [ 07/Apr/16 ]

Still affects 0.14.1.

Comment by PHO [ 06/Mar/16 ]

But skribe, I think your unloader is not very reliable because even without the bug it would take 3 redstone ticks (6 game ticks) for the powered rail to deactivate after the minecart hits the block. I assume 6 game ticks is long enough for the minecart to bounce off.

Comment by PHO [ 04/Mar/16 ]

Confirmed in 0.14.0 alpha / iOS.

Summary: Comparator delays 2 ticks instead of 1 while measuring a container

In my screenshot below, the right side of two hoppers facing each other has 1 item. When the button is pushed, it should take 2 ticks for the comparator to change its state (1 tick for the torch, and 1 for the comp itself). But actually it takes 3 ticks as shown.

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