Cold Smoker Bypass

[NePaSmoKer]

Need some help.

If anyone has a Digital Generator sensor bypass that comes with the new Bradley Cold Smoke Adaptor I would like to buy it from you. Just pm me.

TY

nepas

[Smokin Soon]

Nepa, I may be wrong but the little thingie they give you is just a dummy plug. I assumed it was a shorted plug for some reason, but when I checked with an ohmeter it was open.
I think that it is just a Radio Shack item if you take your cord so they can match. If anyone else has checked this dummy plug, let us know as I have not used my cold smoke setup yet.

[Mr Walleye]

I would think there is more to it than just an open plug because the smoke generator will not run with out the sensor plugged in. I agree it is something very simple that creates the ability to bypass or simulate the sensor.

Mike

[Bradley (Head Office)]

I would think there is more to it than just an open plug because the smoke generator will not run with out the sensor plugged in. I agree it is something very simple that creates the ability to bypass or simulate the sensor.

Mike

You are correct Mike there is a small device in it to simulate the sensor ( I don't know the type or name of it )

But an open plug will not work.

Brian

[NePaSmoKer]

I was going to fit my BPS to this unit. Would work fine in the summer where it could be outside, but dont think i want the flame in the garage in the winter.

nepas

[Mr Walleye]

Thanks Brian

I guess not knowing if the sensor is a thermocouple, an RTD, or a thermistor it's difficult to know. I would assume its a thermocouple. A thermocouple is simply made of 2 dissimilar metals with a connection point. Based on the information below the 2 dissimilar metals when heated produce an electrical current which is measured and displayed as a temperature.

So... what does this mean?
Well... to me it means it should be very easy to bypass this providing your not concerned with the temp that is displayed. The display is showing what current it's getting from the TC and showing it as a temperature. I would bet you could simply take a connector and short the ends our with two dissimilar conductors. Obviously if the circut in the DBS does not sense any current it does not allow anything to run.

Hmmm... almost sounds like an experiment!  ::)

PS... I'm definitely no expert on this and I would consult someone with more expertise in it. I may do some playing with this idea and if I do I will let you know.

It would certainly be easier if someone who has purchased the Bradley Cold Smoke attachment for an OBS would mail NePas the the bypass sensor because they would have no use for it.

Just thinking out loud....

Mike



How does a thermocouple work?

T.J Seebeck discovered in the 1820s that an electric current flows in a closed circuit of two dissimilar metals when one of the two junctions is heated with respect to the other. In a thermocouple circuit the current continues to flow as long as the two junctions are at different temperatures. The magnitude and direction of the current depends on the temperature difference between the junctions and the properties of the metals used in the circuit. This is known as the Seebeck effect. Click here to see an example of the circuit.

If the circuit is broken at the center, the net open circuit voltage (the Seebeck voltage) is a function of the junction temperature and the composition of the two metals.

If the hot and cold junctions are reversed, current will flow in the opposite direction. Any two dissimilar metals can be used and the thermocouple circuit will generate a low voltage output that is almost (but not exactly) proportional to the temperature difference between the hot junction and the cold junction. The voltage output is between 15 and 40µV per degree C, dependant on the thermocouple conductor metals used. The actual metals used in industrial thermocouples depend on the application and temperature measurement range required.

[pensrock]

Mike, if it were only that easy. It can't be a thermocouple because I tried exactly what you mentioned. I bought a connector and soldered the two leads together. When it is plugged in, the BDS shows an 'E' just like the sensor was not connected. Maybe there is a resistor or something like that in the bypass. If someone has one it would be very interesting to see what is inside, it should be very easy to make once the mystery item is discovered.

[Mr Walleye]

Pens

I think whatever it is it must have to produce a current because that's basically what a TC does. Or at least that's how I understand it. When you did that did you us two different types of wire?

Mike

[pensrock]

No because I can short a thermocouple out and it will read ambient temp. We use tons of thermocouples at work and many many times I'll short the connections out to make sure the right wire goes to the correct instrument, when shorted you can see the reading on the instrument change. It doesn't matter if it is shorted at the instrument or at the thermocouple. If you want to try something, unhook the thermocouple on your PID and touch a wire across the two screws, it should read about ambient temp.

I guess I could bring home a piece of actual thermocouple wire, not thermocouple extention wire, and try connecting it. But my gut feeling is it will not work. I'll try to remember to bring a piece home tomorrow. Actual thermocouple wire is made of two dissimilar metals as you mentioned.

[Bradley (Head Office)]

I would think there is more to it than just an open plug because the smoke generator will not run with out the sensor plugged in. I agree it is something very simple that creates the ability to bypass or simulate the sensor.

Mike

You are correct Mike there is a small device in it to simulate the sensor ( I don't know the type or name of it )

But an open plug will not work.

Brian

Maybe i should clarify this better

The Temp sensor in the digital smoker is a Thermistor.
When i said i didn't know the type i meant the type that is installed in the bypass plug.

Sorry for the confusion
Brian

[pensrock]

OK, thanks Brian.

I'll see what I can find out about thermistors at work tomorrow. I know we only we thermocouples but I can check in some of our referance material, it may tell me something.

[Mr Walleye]

Thanks Brian

So Pens... You are probably correct regarding the resistor. I found this regarding thermistors

Thermistors are temperature sensitive resistors.  All resistors vary with temperature, but thermistors are constructed of semiconductor material with a resistivity that is especially sensitive to temperature.

Mike

[NePaSmoKer]

now i'm at at a loss here  :D 

nepas

[pensrock]

I just did some quick googling. Thermistors are a temperature sensitive resistor (like Mike found out), so that being said. If I were to measure the resistance of the thermistor at room temperature, I would think installing a resistor with about the same value would do the trick.

If I can get some time to play at work tomorrow, I'll try to see if it works.


OK Sparky, enough drinking at a distance..... you can jump in anytime and help us out.  ;D

[Mr Walleye]

NePas

Hopefully someone who has purchased the Bradley Cold Smoke attachment for an OBS and doesn't need the sensor bypass designed for the DBS will pass it along to you. At least that would be the simplest...

If not we'll get something figured out...

Mike