Temperature Sensor problems

tacopult

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I have 8 houses, 4 uses Chore Tronics Model 32 and the other 4 Model 40 system to monitor and control lights, fans, etc. I've been getting issues where the newly replaced temp sensors would malfunction the same way as the ones I replaced. Temp readings would go significantly higher or lower than the other nearby sensors, and would erratically climb or fall throughout the day. I followed the manual to check for the usual suspects, moisture in the sensor housing, damaged or corroded wires in the I/O Board, but found nothing. Any ideas?
 
Hi Tacopult and welcome to the Forum.
It sounds as if you're into poultry in a big way - how many birds do you keep in each house? I'm not sure if anyone on here has experience of what sounds like a commercial setup - this is a hobby forum and most of us just keep a few birds for our own pleasure. However, we have some multi-talented people on here so I hope someone can help you.
 
Thanks, Marigold. Seems all I can find are hobby/subsistance farmers online. I may have to fork over $ for professional help.
 
Thats a seriously packed I/O board!
I don't know except that the inputs do seem to be susceptible to EMF by the way they say to place the twisted pairs at 90 degrees to mains wiring. If the board looks dry and happy (and there are no over hot ICs, smell of roasted resistor etc)... Try removing all the inputs and see if you can isolate the problem?
Is it effecting all 8 houses with separate controllers?
 
rick said:
Thats a seriously packed I/O board!
I don't know except that the inputs do seem to be susceptible to EMF by the way they say to place the twisted pairs at 90 degrees to mains wiring. If the board looks dry and happy (and there are no over hot ICs, smell of roasted resistor etc)... Try removing all the inputs and see if you can isolate the problem?
Is it effecting all 8 houses with separate controllers?

90°? I suppose I can give it a try on one of the I/O boards and see what happens. Yes, each house has their own controller, but only 5 houses are having this issue. All dry and happy, or at least content with their lot in life, no heat that I've noticed, no smelll either.
"Remove inputs"?
 
It does seem odd that you are having the same issue with 5 separate systems. If you have eliminated the sensors themselves as a problem then it makes me wonder what has changed with those 5:
I.e is the power to those 5 separate to the other 3?
Some new source of interference?

The manual recommends running sensor wiring at 90 degs to the power. I.e not to run them together in one conduit and if they have to cross then minimise the coupling by crossing them at 90 degrees. But if you haven't changed any wiring lately (or potentially metal objects like poles near the wiring) then there would be no change from before.
By disconnecting the inputs I mean it as a way of diagnosing the problem. As you have a record of readings from them all then this may not be necessary. Is it always the same input lines that are playing up or do they vary?
Other possibilities are that the anolog to digital converter is malfunctioning or even that you have had a software update that is giving erroneous results.
I'm just guessing from general electronic principles!
 
https://photos.app.goo.gl/QFVEsFRNyhghwJ139
https://photos.app.goo.gl/uNGt665JJiWKWXGE8

Here's what I'm working with.
 
Screenshot from 2018-08-10 08-03-36.png

I am presuming that the red and black pairs are the sensor inputs. It might be worth tugging on them very gently to check that none are loose. A fractured wire is another possibility. You could diagnose that by attaching the sensor to that input with a short run of good wire and see if the problem goes away.

Beyond that you probably need an engineer as even they are unlikely to work out what is wrong without being there.

... obviously, if you have a rack of incubating eggs being served by this system right now then, apart from carefully checking for a poor connection, best wait till you can put it out of service for a while and diagnose the issue it when it isn't 'live'.
 
Yes, the red and black pairs are for each sensor. They all check out fine, none loose nor corroded. Fractured? There are places where the lines are pinned against the wall and ceiling by...two nails connected by a piece of plastic to resemble a staple. It isn't very much pressure, and then wires are protected by am addition layer of plastic. But if a fracture happened, I suppose it would be at those sharp curves.
 
I hope this makes sense tacopult but techie language is pretty much unavoidable!
Yes, the most likely explanation is a poor connection (at a terminal or along the wire run due to a fracture) causing a resistance change in the wire. That's if the temperature sensors are 'passive', simply a thermistor in a plug in module. They may be 'active' though (powered through the wires and producing a signal, usually frequency rather than digital) but that would be less susceptible to resistance in the line unless it caused a DC supply fault (possible). More susceptible to mains hum and interference though so I wonder...
I would pick a line where the fault is happening - the unexplained change in temperature reading - trace it from the sensor to the board, marking it with some tape or similar as you go. Is there anything new like a mains run or equipment along the length? If so, does the problem go away if you turn off/isolate that equipment or wiring?
If there seems to be nothing causing interference then try
Removing the wire from the staples and just running it temporarily across the floor. Any change? If not try
replacing the sensor wire with the same guage and preferably colours (red and black.). If that worked staple it back in place.
If the problem still persists on that line then it is definitely time to call someone in.

...Thinking about it, the sensors probably are producing an output signal as a frequency and the red and black wires are signifying polarity (its expensive kit and that would be the better spec way of doing it and explains the need for twisted pairs.) As it is affecting a number of sensors and not just one then it seems very likely to me that you have installed something like a pump or a new mains run maybe that is causing interference? Anything like that happened before the faults started happening? Even a new modem or hands free phone maybe? I'm imagining that your 8 systems are in 8 different sheds? If 5 of them are causing trouble then that would be some pretty big source of interference!

Just wondering, have you disconnected or changed earthing points for power recently like new earth rods or earth straps?
 
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