Temperature sensors' values disappear

[maxvatar]

Hello all,

a technical issue started a week ago (or so) on my LK3.8 v.1.49d. The symptom is that temperature sensors' (DS18B20) values disappear for approx. 5seconds and then come back again. It is happening on one of three sensors directly connected to LK from time to time, but mainly the sensors connected via splitter LANKON-099 are affected (all four sensors). Restart doesn't help. The temperatures are between 20 and 60°C.

The situation is rather annoying, because I have some events based on sensor values and with such problems the events doesn't work properly.

Can anybody give me an advice, what could be wrong?

Thank you in advance.
Best regards
Max

[notek]

Hello Max
What means disappear - the readings are -60 degree?
IF it happen, it means that controller is not able to decode read frames from sensors.
It can be caused by wrong connections but more probably are poor sensors, or long cables.
I newest firmware 1.57a we change little this function, to try more times (more frames) decode and if not success show -60 after longer time.
Maybe it help, but for reliable measurement system I suggest check sensors first. IF they not work correctly alone it is bad sign.
Did you buy this sensors from tinycontrol?

[maxvatar]

Hello Max
What means disappear - the readings are -60 degree?
IF it happen, it means that controller is not able to decode read frames from sensors.
It can be caused by wrong connections but more probably are poor sensors, or long cables.
I newest firmware 1.57a we change little this function, to try more  times (more frames) decode and if not success show -60 after longer time.
Maybe it help, but for reliable measurement system I suggest check sensors first. IF they not work correctly alone it is bad  sign.
Did you buy this sensors from tinycontrol?

Hello Notek,
the value are not -60 degrees, but rather null. The situation lasts for 5 till 16 seconds approx. and then the temperature value come back again. In UI it looks like this:


As I wrote earlier, this started to happen 2-3weeks ago, before that there was no problem at all. The sensors are original LANKON-070.

I have bought another LK3.8, I'm going to try to change the device for a new one. I can flash it with new 1.57a firmware, if you recommend that.

Any other ideas?

Thank you!
Best regards
MaX

[maxvatar]

Hello all,

just to complete this thread - with new LK HW 3.8 on SW 1.57a the problem is solved for now. At least I know, that sensors, wire's length and 1Wire splitters are OK. If there are further problems, I'll post the description here.

Have a nice one.
MaX

[Rudo1111]

Hello, LK3 also happens to me that once in a while the DS18B20 sensor "goes crazy" and shows e.g. -20,-40, see a picture. LK3-SW-1.57a | HW 3.7
I can't insert an image, only a URL 

[maxvatar]

Hello all,
let me reopen this thread - described malfunction still prevails. In cycles of approx 20seconds the values from temperature sensors disappear or reappear. It is important to be mentioned - sensors affected with this flaw are connected to "RJ12 splitter - 4x1-Wire + 1xI2C" and the splitter itself is connected to "RJ12 splitter - 3xI2C/1-Wire + 4x1-Wire", which is then connected to my LK3 (SW 1.61 | HW 3.8). There are three other temperature sensors connected via "tB2 - expansion board with 1-Wire, I2C, OLED" to "RJ12 splitter - 3xI2C/1-Wire + 4x1-Wire" and their reading is uninterupted.
What do you think can be source of the problem:

• serie connection "temperature sensor DS18B20" -> "RJ12 splitter - 4x1-Wire + 1xI2C" ->  "RJ12 splitter - 3xI2C/1-Wire + 4x1-Wire" -> LK3
  
• "RJ12 splitter - 4x1-Wire + 1xI2C" itself, because other temperature sensors connected via "tB2 - expansion board with 1-Wire, I2C, OLED" -> "RJ12 splitter - 3xI2C/1-Wire + 4x1-Wire" are OK
  
• LK3 unit itself? Another thing to be mentioned - I have OLED display connected to LK3, with 4 screens configured to be displayed in cycle of 3sconds via scheduler. It happens from time to time, that random screen freezes on OLED display and the OLED must be disabled/enabled (in OLED menu with SAVE button) to restore the OLED cycling.
  

The problem is rather crucial for me - I have two automatic events configured based on temperature values from sensors with bad reading. When the sensor value is NULL, the event goes off and on randomly.
 
Thank you for you opinions in advance.
Best regards
MaX