DS18B20 configuration webpage issues

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chunter1
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Posts: 82
Joined: 22 Jan 2016, 22:40

DS18B20 configuration webpage issues

#1 Post by chunter1 » 20 Nov 2018, 17:38

I did a clean install of the latest built on a Wemos D1 mini.
When configuring a DS18B20 sensor, the configuration webpage sometimes shows a sensor, sometimes not, sometimes it shows the correct bit-width selected, sometimes not...
It's a total mess each time i reaload the page.
When looking at the log-screen, i see that sometimes the values are not read.
Even more, when i additionally configure a controller that the ESPEasy should send the data to, or when i enable the Wifi indication LED.
Sensor is wired correctly (3-wire, pullup etc.)
Tried several modules, everywhere the same issue.
Anybody knows a solution?

Domosapiens
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Posts: 307
Joined: 06 Nov 2016, 13:45

Re: DS18B20 configuration webpage issues

#2 Post by Domosapiens » 22 Nov 2018, 01:42

Yes, I recognize this.

But first:
the latest built
the latest built is a forbidden word, .. useless text, ...without information.
Almost every day there is a new release. Be precise!

The symptoms look like a DS18B20 in parasite mode, that could be caused by a bad Vcc or Gnd connection.
Also make sure you have a strong pull-up (4.7K down to 2K in case of hairy wires).
Add a 4.7uF ElCo close to the connection point.
Try D5,D6 or D7, the known trouble-free GPIO's (D0 also in my setup).

And then ...
Wemos D1 mini
What GPIO ? Be precise!

There are a number of reports with weak/bad voltage regulators:
See https://www.reddit.com/r/esp8266/commen ... r_on_your/

As the DS18B20 works on the 3.3.V side, it is an extra load to the voltage convertor.
You can try a 47uF ElCo on the 3.3V side to support the onboard capacitor.
Or use a separate 3.3. voltage convertor.

In total I bought 77 DS18B20 sensors from different shops.
Recently I have experienced a "bad" (?) batch of #5 DS18B20 from Ali supplier: Shop1280487 Store, that shop is gone now!
Later a good batch of #5 from http://www.aliexpress.com/store/1916536 ... 4c4dYjtXez
So you could have a bad batch!

I use this meter: https://nl.aliexpress.com/item/GM328-Mu ... Title=true to check the connections.
It shows 2 diodes from GND to VCC and Data.
In that way, I know that my wiring is correct.

Here also a report from an unexplained problem with DS18B20:
https://github.com/letscontrolit/ESPEasy/issues/1723

You could try a release of a long time ago.
ESPEasy_mega-20180323 is reported as more than 150 day stable.
(sorry, can not find a GitHub link)
For my production environment I use ESPEasy_v2.0.0-dev11 running all the time, with an automatic reboot before the 49day bug comes in!
30+ ESP units for production and test. Ranging from control of heating equipment, flow sensing, floor temp sensing, energy calculation, floor thermostat, water usage, to an interactive "fun box" for my grandson. Mainly Wemos D1.

chunter1
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Posts: 82
Joined: 22 Jan 2016, 22:40

Re: DS18B20 configuration webpage issues

#3 Post by chunter1 » 01 Dec 2018, 22:51

But first:
...the latest built is a forbidden word, .. useless text, ...without information.
Almost every day there is a new release. Be precise!
Neither useless, nor forbidden... actually totally simple - just look at the date of the posting. ;)
The symptoms look like a DS18B20 in parasite mode, that could be caused by a bad Vcc or Gnd connection.
Also make sure you have a strong pull-up (4.7K down to 2K in case of hairy wires).
Add a 4.7uF ElCo close to the connection point.
Try D5,D6 or D7, the known trouble-free GPIO's (D0 also in my setup).
All well and ofcourse no parasite mode with 12 sensors in a line.
EMI issues, brownouts or voltage stability issues definately no - always checking signal integirty with the scope.
What GPIO ? Be precise!
Does definately not depend on GPIO.


Why should the web-interface show different sensor addresses in the task setting almost each time i reload the page if there was a hardware issue?
It's definately a software issue.

BAnton
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Posts: 1
Joined: 20 Nov 2018, 13:57

Re: DS18B20 configuration webpage issues

#4 Post by BAnton » 05 Dec 2018, 15:15

The entire plugin Dallas is broken since https://github.com/letscontrolit/ESPEas ... 6e4356031d.

Namely it provides stale data and violates the 1-wire bus.

Solution: use prior version

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grovkillen
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Location: Hudiksvall, Sweden
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Re: DS18B20 configuration webpage issues

#5 Post by grovkillen » 05 Dec 2018, 20:31

BAnton wrote: 05 Dec 2018, 15:15 The entire plugin Dallas is broken since https://github.com/letscontrolit/ESPEas ... 6e4356031d.

Namely it provides stale data and violates the 1-wire bus.

Solution: use prior version
I didn't know that. Could you open a new issue on GitHub?
ESP Easy Flasher [flash tool and wifi setup at flash time]
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Official shop: https://firstbyte.shop/
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chunter1
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Posts: 82
Joined: 22 Jan 2016, 22:40

Re: DS18B20 configuration webpage issues

#6 Post by chunter1 » 06 Dec 2018, 22:36

I finally took a look at the "_P004_Dallas.ino" plugin code.
Found that the 1-wire communication part and timing is not optimal.
Especially if wires are a bit longer (my bus is 4 meters with 12 sensors) the existing code provocates unstable behaviour (as i described in the opening post).
I changed the code to be on the secure/conservative side in compliance with the timings in the datasheet.
Ofcourse it needs some more testing - but so far the issues have completely gone :)
Maybe somebody can check in parallel before i open a pull request?

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