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MarkBall2
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 Posted: Sat Apr 17 10 1:52 pm Post subject: |
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Either way works for me. I'm not an engineer, but am very mechanically inclined and can read a wiring diagram.
That said, maybe one is to be kept simple, the other be more "robust" and technical. That way both crowds/skill levels can choose which direction they want to go.
Either way, I'm learning from this thread.
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Mark
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JimmieOhio
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Joined: 11 Mar 2008
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| Posted: Sat Apr 17 10 8:36 pm Post subject: |
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KillSwitch, I apologize for going off on a high tech tangent and complicating things.
The thing that got me thinking was this reference everyone makes about a PID controller. This application is NOT a really a PID application.
The short and simple answer is that for fan control, a PID-capable controller really only works in "on-off" mode because pulsing the fan cannot happen too frequently or you will burn it up. And PID-capable controllers are no more expensive than controllers designed for on-off mode only.
At the end of the day, you are simply making a thermostat for your firebox. Temperature input and fan output based on the temperature feedback.
What did you think about my solenoid toggling idea with the fan on continuously?
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Jimmie Ohio
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"Never criticize a man until you have walked a mile in his shoes. Then, criticize him all you want since you're a mile away and you have HIS shoes." |
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Soybomb
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Joined: 10 Nov 2009
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| Posted: Sat Apr 17 10 8:57 pm Post subject: |
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Killswitch, holler if you want us to start a new thread but it seems like this is general controller discussion right now.
I could use some thermocouple advice from you more experienced guys. I have a wsm and hate snaking cords through it for thermometers. I'm thinking about getting a 12" long probe and putting some eyelets in the cooker. Then when its time to cook, just stick the probe in through the eyelet and let it hang out. Seems easy. My only concern is will the extra hot temps coming up the side of the bullet radiate down the length of my probe and skew the temp and not give a true tip reading? |
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killswitch505
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Joined: 05 Apr 2009
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Location: Hobbs, NM
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| Posted: Sat Apr 17 10 10:13 pm Post subject: |
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| JimmieOhio wrote: |
What did you think about my solenoid toggling idea with the fan on continuously? |
I actually like the pulse because it helps with over shoot on the temps Shawn the (guy I built the first one for) turned that feature off and found that it would over shoot like 10-15 degrees and it only pulses when it comes with in 10 degrees of the set point I know that its not a sever duty motor but I’m more then confident the fan and the pid will be able to handle this. The fan you specified in your post is the same fan used on the guru well 12vdc not 24vdc (the same as I planned on using on my newest build I’ve already bought 3 of them) and it pulses I might need to shoot them an email letting them know that it wont work or that’s how its not indented to work actually Jimmie will you please do that for me I’m a little busy this week
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| Mrs. K.A.M. wrote: | Those are some of the best looking wieners I've ever seen  |
Last edited by killswitch505 on Sun Apr 18 10 8:41 am; edited 3 times in total |
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killswitch505
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| Posted: Sun Apr 18 10 7:19 am Post subject: |
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| Soybomb wrote: | Killswitch, holler if you want us to start a new thread but it seems like this is general controller discussion right now.
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no way man I love it I think its what the ring is all about as long as it stays remotely on the subject and no one starts bad mouthing the Chargers lol
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| Mrs. K.A.M. wrote: | | Those are some of the best looking wieners I've ever seen |
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killswitch505
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| Posted: Sun Apr 18 10 8:42 am Post subject: |
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| Mrs. K.A.M. wrote: | | Those are some of the best looking wieners I've ever seen |
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killswitch505
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animal
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Location: Wisconsin
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| Posted: Sun Apr 18 10 8:45 am Post subject: |
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| What value of resistor do you use with the k Thermocouple |
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killswitch505
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| Posted: Sun Apr 18 10 10:02 am Post subject: |
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| animal wrote: | | What value of resistor do you use with the k Thermocouple |
sorry man I don’t really understand the question and im not sure where or why you would want to insert a resister in a thermoelectric circuit. When you take 2 wires that are dissimilar and join them if you and heat this union a voltage is produced that voltage is measured and that is where you get your temp from I cant see where you would want a resistor in this part of the circuit. Now if you asking what kind of resistor the controller may have built into it I have no idea I would need to see a diagram of the PCB most companies consider this proprietary and wont give out this info but I can think of some here that probably knows (please help this guy Jimmie lol)
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| Mrs. K.A.M. wrote: | | Those are some of the best looking wieners I've ever seen |
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k.a.m.
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| Posted: Sun Apr 18 10 10:18 am Post subject: |
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killswitch505, I have read through your thread and have to say Kudos my Man.  I am not really into the electronics end of the cookers but for those that are you have created a valuable tool. Nicely done my man.
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animal
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Location: Wisconsin
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| Posted: Sun Apr 18 10 8:34 pm Post subject: |
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| killswitch505 wrote: | | animal wrote: | | What value of resistor do you use with the k Thermocouple |
sorry man I don’t really understand the question and im not sure where or why you would want to insert a resister in a thermoelectric circuit. When you take 2 wires that are dissimilar and join them if you and heat this union a voltage is produced that voltage is measured and that is where you get your temp from I cant see where you would want a resistor in this part of the circuit. Now if you asking what kind of resistor the controller may have built into it I have no idea I would need to see a diagram of the PCB most companies consider this proprietary and wont give out this info but I can think of some here that probably knows (please help this guy Jimmie lol) |
Sorry, I got the damn thing with no documentation They sent me a different model than I ordered, surprise surprise. I hooked up the thermocouple and got an error message, saw the jumper spot on the back for a resistor to - Thermocouple connection. Tried different value resistors and got a reading. Then found a pot with that approximate range and dialed her in. This morning I found the manual and printed it off, was able to enter the programming mode and found I don't need the resistor once I enter the type of thermocouple I am using. |
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animal
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Location: Wisconsin
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| Posted: Sun Apr 18 10 8:42 pm Post subject: |
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| Time to start the ribs and ABT's, looks like I am still using the Lang the old fashioned way until next time |
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JimmieOhio
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Joined: 11 Mar 2008
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Location: east side of Cleveland, Ohio
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| Posted: Sun Apr 18 10 9:36 pm Post subject: |
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| killswitch505 wrote: | | animal wrote: | | What value of resistor do you use with the k Thermocouple |
sorry man I don’t really understand the question and im not sure where or why you would want to insert a resister in a thermoelectric circuit. When you take 2 wires that are dissimilar and join them if you and heat this union a voltage is produced that voltage is measured and that is where you get your temp from I cant see where you would want a resistor in this part of the circuit. Now if you asking what kind of resistor the controller may have built into it I have no idea I would need to see a diagram of the PCB most companies consider this proprietary and wont give out this info but I can think of some here that probably knows (please help this guy Jimmie lol) |
Not only is it a voltage, it is millivolts (that's thousandths of a volt = 0.001). Thermocouples are used directly, no need for a resistor of any kind.
And KillSwitch, thanks for the links. The one I really like is the trunk lifter. You could adapt that to a cooker door easily. Wiring I'm pretty good at since my parents ran a control panel company years ago. That's where I learned a lot, even compared to four years of college.
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Jimmie Ohio
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"Never criticize a man until you have walked a mile in his shoes. Then, criticize him all you want since you're a mile away and you have HIS shoes." |
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killswitch505
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Joined: 05 Apr 2009
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Location: Hobbs, NM
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| Posted: Sun Apr 18 10 11:59 pm Post subject: |
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| Quote: | | Not only is it a voltage, it is millivolts (that's thousandths of a volt = 0.001). Thermocouples are used directly, no need for a resistor of any kind. |
thanks Jimmie i knew you could add to my reply
P.S. jimmy do you think animal might have crossed the tc wires I know if you land them backwards they will read reverse or the controller might even see it as an error and most controller fail high (or fail open) animal
send me or jimmie a part # it might not be a type k PID[/quote]
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| Mrs. K.A.M. wrote: | | Those are some of the best looking wieners I've ever seen |
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JimmieOhio
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Location: east side of Cleveland, Ohio
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| Posted: Mon Apr 19 10 3:50 pm Post subject: |
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| killswitch505 wrote: | P.S. jimmy do you think animal might have crossed the tc wires I know if you land them backwards they will read reverse or the controller might even see it as an error and most controller fail high (or fail open) animal
send me or jimmie a part # it might not be a type k PID |
Each type of thermocouple has its own color code. Polarity is absolutely important.
Type K is chromel (+) / alumel (-) with positive being yellow and negative being red.
Type J is another type of commonly used thermocouple and is easy to tell which is which, even blindfolded since it is iron (+) / constantan (-). Iron is magnetic, so with any simple magnet, you can tell which conductor is which.
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Jimmie Ohio
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"Never criticize a man until you have walked a mile in his shoes. Then, criticize him all you want since you're a mile away and you have HIS shoes." |
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Soybomb
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Joined: 10 Nov 2009
Posts: 373
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| Posted: Mon Apr 19 10 9:24 pm Post subject: |
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Speaking of temperature sensing devices, do you guys know if you can get away with extending the wires on a thermistor? As I'm planning my pid control box I can't help but get the urge to integrate my maverick et-73 sender unit in it too. I have no idea what kind of resistance range a thermistor falls into though and if the wire extensions might introduce too much error into it.
So what kind of temp bounce do you normally see killswitch? As I'm reading other stuff it seems like some people feel the big bolt thermocouple might be slow to respond to temp shifts and cause temp flux. I'm wondering if its worth the extra bucks to get a thinner one or if cheap really works fine. |
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JimmieOhio
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| Posted: Mon Apr 19 10 9:59 pm Post subject: |
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| Soybomb wrote: | | So what kind of temp bounce do you normally see killswitch? As I'm reading other stuff it seems like some people feel the big bolt thermocouple might be slow to respond to temp shifts and cause temp flux. I'm wondering if its worth the extra bucks to get a thinner one or if cheap really works fine. |
I'm using type K thermocouple for two reasons:
1) The ones I got are industrial grade. Many can be ordered with armored sheathes that will protect them from pinches. They will also hold up to the elements, unlike the cheaper temp probes. Accuracy is within a degree and you always know the tip is the sensing point.
2) ThermoWorks makes Thermopens using a type K thermocouple. That's good enough for me.
Although the caveat of using a thermocouple may be the fact that you can't extend it using lamp cord from Wal-Mart and thermocouple extension wire runs about $1 per foot, you can always order them either with longer leads or locate your control box within six feet of the probe. My thermocouples from ThermoWorks were 78" long standard.
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Jimmie Ohio
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"Never criticize a man until you have walked a mile in his shoes. Then, criticize him all you want since you're a mile away and you have HIS shoes." |
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Soybomb
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Joined: 10 Nov 2009
Posts: 373
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| Posted: Mon Apr 19 10 10:26 pm Post subject: |
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| JimmieOhio wrote: | | Soybomb wrote: | | So what kind of temp bounce do you normally see killswitch? As I'm reading other stuff it seems like some people feel the big bolt thermocouple might be slow to respond to temp shifts and cause temp flux. I'm wondering if its worth the extra bucks to get a thinner one or if cheap really works fine. |
I'm using type K thermocouple for two reasons:
1) The ones I got are industrial grade. Many can be ordered with armored sheathes that will protect them from pinches. They will also hold up to the elements, unlike the cheaper temp probes. Accuracy is within a degree and you always know the tip is the sensing point.
2) ThermoWorks makes Thermopens using a type K thermocouple. That's good enough for me.
Although the caveat of using a thermocouple may be the fact that you can't extend it using lamp cord from Wal-Mart and thermocouple extension wire runs about $1 per foot, you can always order them either with longer leads or locate your control box within six feet of the probe. My thermocouples from ThermoWorks were 78" long standard. |
The impression I got was that people weren't really doubting the accuracy of a thermocouple, as much as how the packaging of the thermocouple effects its time to read. Case in point, the thermapen. The tip is very very fine and the thermocouple is likely grounded so it reads very very quickly. With the large bolt ended thermocouples that generally constitute the cheapies, who knows how much thicker the metal is and if the thermocouple is grounded or not. After 15 seconds they might register the same temperature as a thinner probe, but if the thinner/grounded enclosure registered it after 1 second it could have signaled its controller to quit stoking the fire that much earlier. The end result, at least for them, was that a big/thick bolt like thermocouple like this http://www.lightobject.com/16ft-5M-K-type-Thermocouple-P406.aspx might make your pid overshoot by reading slower than a thinner probe. But those were mostly electric smokers. I figured I'd see what our own killswitch has seen in practice. |
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JimmieOhio
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Joined: 11 Mar 2008
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Location: east side of Cleveland, Ohio
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| Posted: Tue Apr 20 10 1:31 am Post subject: |
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Soybomb,
Don't confuse a thermocouple in a cooker that is reading constantly with an INSTANT read thermometer.
This thread is dealing with an ongoing monitoring process, so any kind of tip, thick or thin, to read continuous temps is not the same as the need to plunge a probe into meat and have the temp settle out in a matter of seconds.
Apples and oranges.
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Jimmie Ohio
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"Never criticize a man until you have walked a mile in his shoes. Then, criticize him all you want since you're a mile away and you have HIS shoes." |
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Soybomb
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Joined: 10 Nov 2009
Posts: 373
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| Posted: Tue Apr 20 10 1:43 am Post subject: |
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Not to be difficult, but how come? Isn't a thermocouple that can report temp changes to the controller more quickly going to allow that controller to react to them with greater accuracy? If the air temp is 265 by the time the thermocouple sends 255 it seems like you could create a very circular chasing problem.
I'd liken it to being on the caboose of a train and calling for the conductor to stop. If I can radio the message to him we'll get the train stopped a lot quicker than if we have to relay the message through every car in the train. |
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