Ladder Logic DIN, sluggish/no response

clearwaterbrewer · Post by **clearwaterbrewer** » Thu Aug 25, 2011 6:56 am

I have momentary button on a digital input in a contactor sealing circuit on rungs 2-3 of the following ladder logic diagram (now working in 3.4.3, thank you!), but the Din0 and Din1 take a full 2 seconds to be recognized... I tried one-shot on and off, no difference.. is there a scanning rate of the ladder logic? If I press a button, I really need it to recognize it very quickly...

-mike

: Din0 - OFF.png (10.63 KiB) Viewed 5798 times

ECC · Post by **ECC** » Thu Aug 25, 2011 7:19 am

Scan time is 100ms. The 2sec delay that you are seeing is just the refresh rate of the display on your browser. When you hook it up to something real you will see it happen instantly.

Post by **JonW** » Thu Aug 25, 2011 8:11 am

I'm using a Din to cancel the hardware alarm. While it is not a full 2 seconds, I do have to push and hold it to cancel the alarm versus just being able to momentarily push it.

ECC · Post by **ECC** » Thu Aug 25, 2011 8:32 am

We debounce the inputs for 160ms... maybe that's a little excessive, could probably halve that so at least it fits within a scan.

clearwaterbrewer · Post by **clearwaterbrewer** » Thu Aug 25, 2011 1:41 pm

here is a youtube video showing 2 seconds http://www.youtube.com/watch?v=44YvttEtXDc

Post by **JonW** » Sun Sep 04, 2011 8:33 pm

I brewed again today and made extensive use of the alarm output for hop additions, process changes, etc. I had to press and hold the button I put on a DIN to cancel the alarm for a good two seconds every time. It seemed like it occasionally even took longer. I know this isn't exactly a bug, but it is pretty annoying.

clearwaterbrewer · Post by **clearwaterbrewer** » Tue Sep 06, 2011 11:24 am

I will probably wire up a 555 timer as a one-shot for the inputs that need it... unless we hear a faster scan rate is in the works... hint, hint

ECC · Post by **ECC** » Tue Sep 06, 2011 9:30 pm

This turned out to be a bug in the ladder logic. Its actually a nasty little bug, the DIN contacts incorrectly used a variable that was only updated when the interface requested a refresh. So if a browser wasn't connected, the DIN contact wouldn't close.

Thanks for finding this. I think the ladder logic feature is finally getting some real-world testing.

Fixed in v3.4.4

clearwaterbrewer · Post by **clearwaterbrewer** » Wed Sep 07, 2011 5:56 am

Works great! Thanks!

ECC · Post by **ECC** » Wed Sep 07, 2011 6:38 am

I updated the topic title to be a little more descriptive in case others are searching for a solution to this problem.

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Ladder Logic DIN, sluggish/no response

Ladder Logic DIN, sluggish/no response

Re: 2-sec delay for recognizing Digital Input?

Re: 2-sec delay for recognizing Digital Input?

Re: 2-sec delay for recognizing Digital Input?

Re: 2-sec delay for recognizing Digital Input?

Re: 2-sec delay for recognizing Digital Input?

Re: 2-sec delay for recognizing Digital Input?

Re: 2-sec delay for recognizing Digital Input?

Re: 2-sec delay for recognizing Digital Input?

Re: Ladder Logic DIN, sluggish/no response