Those K-Type Thermocouples appear to be good for up to 1100°C
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I've got the exact same setup, but...
I have the thermocouple on the top shelf of the insert.
The insert's fan has two speeds, low and high.
The temp controller now starts up the fan on low when temp hits 200F, switches to high at 700F, and the reverse.
I used to have it send a notification via an ecolink contact sensor, but got tired of the stove's inaccurate ways with its native thermo switch, that I replaced its action with the pid/thermo switch. I had to give up the warning, but realistically, I should be able to hear the high speed of the fan in the house, and I shouldn't be leaving the house until the burn is stabilized to my arbitrarily selected temp of below 700F.
I too would be very interested in a simple instrumentation deal. Something like, gee, I wonder what the stove temp is now? Or, what was the temp profile of my last burn using x wood?
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I was researching yesterday and found out what I need is a thermocouple transmitter. It's basically an amplifier circuit that takes the DC microvolt output of the thermocouple and brings it up to a linear 0-10vdc signal. It looks like what that guy is using in the video. I also ordered a Fibaro Smart Implant to connect it to. I'm not sure how accurate it will be or how I will handle the data translation to degrees, but it will give me something to start out and play with.
I will probably just add an additional thermocouple into my flue pipe for this new setup so that I can continue to use the display/sensor that I already have.
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How about something like this?
It says it's compensated.
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Yep, that's it
How would you convert the voltage readings that the Implant reports to temperature?
(This is probably beyond my capability.)
edit: maybe this driver will do it?
The smart implant driver supports entering an equation directly in the device page to convert voltage to temperature, even if it is not linear. See this post: [RELEASE] Fibaro Smart Implant FGBS-222 - #107 by christi999.
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Excellent, thanks.
I might actually spend money on this, lol.
I wonder if the amplifier and an existing pid temperature controller could share a thermocouple, or would each need a dedicated thermocouple?
Typically thermocouple inputs are high impedance. If you use the "Isolated Thermocouple to Analog Converter" you should be able to share. Mostly because of the isolation in the amplifier will not result in grounding (common) issues between the amplifier and PID controller.
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From what I have seen in researching this the past few days, it won't work. I ended up buying a new pid controller with analog 0-10vdc output this morning. Now I can use my existing thermocouple, get a nicer looking controller, and an output to Hubitat. Should be here Monday. The thermocouple transmitter I already ordered was coming from China, so who knows when I would have seen it.
Dwyer had 32 in stock this morning of the 32B-63-LV. The LV stands for low voltage. The non LV runs off 110V
https://www.dwyer-inst.com/Product/Temperature/ProcessControllers/Series32B
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Thanks very much. How the heck did you find that? Awesome.
It's too bad there doesn't seem to be one with linear voltage output as well as two relays, vs one. I've been using both relays on my existing Auber.
edit: You know, I'm thinking the output of the controller, 0-10v, is going to want to control a device to a setpoint, so it wouldn't be related to the actual temperature, just the difference from the setpoint. I'm so confused.
No doubt there will be some tinkering required. I am thinking the set point will likely be set to the highest anticipated stove temp. As the process (actual) temp approaches the set temp, the voltage output will change in a linear way.
But don't take my word for it. I'm guessing at this point, but optimistic in making it work.
I also saw some controllers that had temperature retransmission, but could not find documentation on how this works. It does not show the values that it would retransmit at. Since it's just retransmitting, I would assume it is at thermocouple/microvolt levels, not 0-10 volt levels.
If we really knew what we were doing we'd be using the RS-485.
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Yeah I was wondering what that was. The one I ordered has the feature, but hell if I know how to use it haha.
Those retransmitting units go for ~400 bucks!
The G series have retransmission, but don't seem to be in stock and the smallest size is 1/16 din (way too big for the wife approval factor since it mounts to the bottom of our mantle).
Seems like a good brand though. Stumbled on them from a beer brewing site that it was mentioned on.
https://www.dwyer-inst.com/Product/Temperature/ProcessControllers/Series16G-8G-4G
You are correct....
I would use something like the unit below to convert the thermocouple to 4-20 mA signal. Very easy to loop this signal output through multiple device inputs and to convert to 1-10 V (for the Fibaro) by using a 500 ohm resistor as a "jumper." Better double check the math on the resistor value before taking my word for it.
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I've used these at work (where it's not my money and reliability is key). If memory serves, it's close to $1,000. The version with a display is a couple hundred more.
I recieved this pid controller yesterday/early, and was looking through the manual. A couple of interesting points: the zero reset is able to be turned off on it, so it will not constantly adjust the output based on the difference between the process value and the set point. It will always maintain output at a 1:1 ratio with this turned off. Also, the output can be changed between heat and cool modes, so it will either increase or decrease voltage output in relation to input, depending on mode selected. There is also an offset value that can be applied to the output, in case the output needs to be within a certain voltage range.
Very cool. I'm much more confident I will be able to make this work in proportional control mode only.
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I installed your driver using the package manager, but I am unable to see any actual values of the analog input sensor. I have input 1 operating mode set to 'analog input without internal pullup'. I have a strange feeling I did not install the driver correctly. Does this seem correct?
Edit: after rereading the driver thread again, I realized that it was user error after all. I installed the device, then your (much better) driver. I needed to hit the reinstall action. All good now. It's connected to the pid controller. I played with the proportional band settings until I was able to get a smooth linear voltage transition from just over 1 volts at 70 deg F, to 9.8 volts at just over 600 degrees F. I just have to figure out the calculation to temperature and put it in the settings and it's done.
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