• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

1wire temperature sensor - working conditions 0-300 degrees C

arhi

Member
anyone have any knowledge of 1wire temperature sensor (like DS1820)
that can work in environment with temperatures 0-300 degrees C.

attm I use temperature to resistance transducers but they require too many wires :( .. as I would like to put approx 50 sensors inside the oven, the one wire ones would make the job much easier/cheaper then temp->resistance ones.

The size does not matter, the sensors need to be mounted inside the oven (12m*4m*4m) on the rails to measure temperature in different regions in the oven. The signal will go trough metal rails (3 metal bars make a rail - but I can make it 4 if I cannot find 1wire device so some 2wire i2c/can/xyz will do the job too)

I know that 12m will work ok for the 1wire .. the i2c will not work on that distance so afaik the 1wire is best for this sort of job, only, ds1820 is limited to 130C and would probably melt around 300C

ATTM I have only 4 transducers (temp->resistance) that I read with uC and control the temperature in the oven, but that works ok for smaller oven's, for 12m length I need more sensors and that makes the temp->resistance ones pretty useless.

EDIT: I need precision of 1 degree C
 
Last edited:

Leftyretro

New Member
Most normal semiconductor components can't live and work in 300c temp.

The normal practice is to place the measurement end of the thermocouples in the oven and route their leads out through high temp seals and then attach to the electronic components that process the sensor's voltage output.

Most ovens have lots of external insulation so mounting electronics on the outside of the oven should not be a problem. Most applications like you have in mind would use a micro based signal processing and multiplexing circuits and utilize some standard communications protocol to a remote host.

Alternaly a industrial standard PID controller could be mounted locally to the oven to perform the control function. However your requirement to use 50 TC sensors will require some kind of none standard method to utilize these measurement. Do use wish to average the 50 sensors to one overall measurement to be used for control or are you going to control on the highest or lowest sensor? Is there a single temperature controlled element (electrical heating elements I assume?) or many controlled temperature elements used in your single oven?

Lefty
 
Last edited:

arhi

Member
@Leftyretro yup I know most of them will not survive the conditions I need them to work in, that's why I posted the question :) hoping someone will prove me wrong and point me to part that might work :)

The project is actually quite simple, I have oven 12x4x4m. The oven is heated via electrical heating elements positioned around the oven. The heating elements are grouped in segments, and each segment can be controlled separately. The job oven is used for require
- no fan can be used (so I cannot use fan to "mix" the air inside the oven)
- equal temperature throughout the oven

At the moment, in smaller oven (4x4x2m) I use temperature to resistance transducers (4 of them) that are positioned in "key" parts of the oven to control 4 heating segments. The transducers are connected to the "control box" via 3mm wire insulated with porcelain "bits".

To control the 12x4x4m oven, I need much more (50 is too much, but I might use the same solution for something else, or some bigger oven, for this one ~20 sensors would do) then 4 sensors and running 40 wires trough the oven ain't pretty/easy/cheap/... not to mention, I need then 40 AD inputs .. (ok, I can use SPI/I2C ADC's as I do not need high readout speed so that can be solved that way)...

In general, I can "automatize" this oven with same technology I'm using for smaller ones, but with 1wire device that can withstand the temperature, I can get much better results
 

Leftyretro

New Member
@Leftyretro yup I know most of them will not survive the conditions I need them to work in, that's why I posted the question :) hoping someone will prove me wrong and point me to part that might work :)

The project is actually quite simple, I have oven 12x4x4m. The oven is heated via electrical heating elements positioned around the oven. The heating elements are grouped in segments, and each segment can be controlled separately. The job oven is used for require
- no fan can be used (so I cannot use fan to "mix" the air inside the oven)
- equal temperature throughout the oven

At the moment, in smaller oven (4x4x2m) I use temperature to resistance transducers (4 of them) that are positioned in "key" parts of the oven to control 4 heating segments. The transducers are connected to the "control box" via 3mm wire insulated with porcelain "bits".

To control the 12x4x4m oven, I need much more (50 is too much, but I might use the same solution for something else, or some bigger oven, for this one ~20 sensors would do) then 4 sensors and running 40 wires trough the oven ain't pretty/easy/cheap/... not to mention, I need then 40 AD inputs .. (ok, I can use SPI/I2C ADC's as I do not need high readout speed so that can be solved that way)...

In general, I can "automatize" this oven with same technology I'm using for smaller ones, but with 1wire device that can withstand the temperature, I can get much better results

Well good luck with your search for hi temp semiconductor devices. The highest I've ever read about were some Motorola devices designed for installing in oil well drilling applications where the sensors were at the drill bit end, thousands of feet down into the well being drilled, but I seem to recall a 350F limit (176C) so not enought for your furnace. This was several decades ago so maybe they have made some advances in max temp specs that I haven't come across. Even if you find such I'm sure the costs would knock your socks off ;)

Lefty
 

arhi

Member
Well good luck with your search for hi temp semiconductor devices.
Thanks anyway .. I think I'm doomed to use the same transducers I use ATTM, and a lot of wires ... the oven is custom made (by me) so I can place the sensors where I need them and "hide" the wire's .. but I wanted to check if someone know about some 1/2w devices that might fit the description :( .. I already did research and find nothing before I posted a question here .. the best I was able to find are some 200C but those are not good enough ..
 

Pommie

Well-Known Member
Most Helpful Member
Just out of curiosity, can I ask, what the oven is used for that it needs such precise control and high temperature.

Mike.
 

arhi

Member
Just out of curiosity, can I ask, what the oven is used for that it needs such precise control and high temperature.

Mike.
of course Mike, I forgot to mention it :)

Oven is not used for anything "high tech" it is used for powder coating. Thing is, with 99% colours the tolerance is 10 degrees or even more, and on top of that, most of the colours are cured at 100-150 degrees C. But, yup, there is always that "but", there are few colours that have very low tolerance ... they will produce different shade at +-3 degrees .. and that is usually not a problem, but, some long metal stripes used for "shaders" are often coated, and if temperature vary more then 3C they get different shade and you can see that on 12m stripe .. on top of that, the batch from one oven need to be same as the batch from another one ...

The problem is that different colours cure at different temperatures .. most from 100-150 .. but then again, some need ~280C ... and for some materials, you need to heat the material to ~300C and then coat it, after that cure at ~120C .. so the oven itself go up to 300C so any probe that goes in must withstand 300C

The QoS will pass even on 5C margin, as the shade, even different, is not noticeable by naked eye, but the problem is, when you are on ~200C it is not easy to up/down temp by 1C so you need good resolution in order to react on time .. another problem is, you cannot compensate for human error, so those thing you can compensate, you have to :)

For 99% colours, 1 analog thermostat connected to relay switching the heaters on/off is enough for 20x6x4m oven... the problem is that 1% :)
 

DTF

New Member
Thanks anyway .. I think I'm doomed to use the same transducers I use ATTM, and a lot of wires ... the oven is custom made (by me) so I can place the sensors where I need them and "hide" the wire's .. but I wanted to check if someone know about some 1/2w devices that might fit the description :( .. I already did research and find nothing before I posted a question here .. the best I was able to find are some 200C but those are not good enough ..
Arhi, can you please share with me the name of the 200 C one wire senzor?
 

JimB

Super Moderator
Most Helpful Member
Arhi, can you please share with me the name of the 200 C one wire senzor?
Arhi was last seen here in 2016.

JimB
 

Visitor

Active Member
Start a new thread, spelling out what you need.

Suggestion – the title should be more than "Need Help"
 

Latest threads

EE World Online Articles

Loading

 
Top