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Rbeckett · 06-13-2012, 10:12 PM

I found a bunch of two and 3 pin screw on connectors for pretty cheap on feebay. Heres a number I used: http://www.ebay.com/itm/180429630024?ssPageName=STRK:MEWNX:IT&_trksid=p398 4.m1439.l2649.

Heres the 2 pin version for thermocouples and sensors too: http://www.ebay.com/itm/170849224254?ssPageName=STRK:MEWNX:IT&_trksid=p398 4.m1439.l2649.

And heres ther power in connectors I got today: http://www.ebay.com/itm/110858711894?ssPageName=STRK:MEWNX:IT&_trksid=p398 4.m1439.l2649

Those vendors shipped pretty fast and the connectors are excelent quality. Probably make you miss your Birthday deadline though...
Bob

**carlisle_bob** · 06-13-2012, 10:39 PM

Hi

Be careful with those connectors for thermocouples. They are fine for thermistors or RTD's. For thermocouples you really want something made from the same metals as the thermocouple it's self.

Bob

Rbeckett · 06-14-2012, 12:43 AM

Carlisle,
Isnt the cold junction thermocouple going to cancel any accumulated error from the TC by comparing the cold junction value? I thought that was the reason that I was supposed to use that configuration to eliminate resistance and reading errors. Do you have a circuit diagram for what you have been using? Even just a napkin drawing would help. Any info you can share would be appreciated, just remember I am also an electronic noob so I have to get some stuff spoon fed so I can piece it together. TIA..
Wheelchair Bob

ClaudiusB · 06-14-2012, 05:20 AM

Quote:

Originally Posted by Rbeckett

Carlisle,
Isnt the cold junction thermocouple going to cancel any accumulated error from the TC by comparing the cold junction value? I thought that was the reason that I was supposed to use that configuration to eliminate resistance and reading errors. Do you have a circuit diagram for what you have been using? Even just a napkin drawing would help. Any info you can share would be appreciated, just remember I am also an electronic noob so I have to get some stuff spoon fed so I can piece it together. TIA..
Wheelchair Bob

Thermocouple connectors, choose K or J depending on your type.

http://www.omega.com/toc_asp/subsectionsc.asp?book=Temperature&subsection=G05&f lag=1

**carlisle_bob** · 06-15-2012, 12:54 PM

Quote:

Originally Posted by Rbeckett

Carlisle,
Isnt the cold junction thermocouple going to cancel any accumulated error from the TC by comparing the cold junction value? I thought that was the reason that I was supposed to use that configuration to eliminate resistance and reading errors. Do you have a circuit diagram for what you have been using? Even just a napkin drawing would help. Any info you can share would be appreciated, just remember I am also an electronic noob so I have to get some stuff spoon fed so I can piece it together. TIA..
Wheelchair Bob

Hi

Ok, first some theory. Any junction between two different metals is going to be a thermocouple. To do a good job running them as a thermometer you want a thermocouple at the thing you are measuring. Two metals contact there, call them A and B. Since they don't make op-amps out of "thermocouple stuff" you need to have two more thermocouples in the circuit. One is metal A to copper the other is metal B to copper. You then measure the voltage copper to copper. Measure the temperature of the second two thermocouples and correct things. Net result is you can calculate the temperature of the first thermocouple.

The gotcha is you need to *know* the temperature of the second two thermocouples. They don't *have* to be at the same temperature, but wow is it complicated if they are not. The only practical way to do it is to bring the thermocouple metal up to a nice massive block and connect to copper there. Then measure the temperature of that block.

The need for that block and the fiddly stuff to make it work is what makes thermocouples a pain. The connector stuff is pretty easy, you just get the ones they specifically make for the exact type of thermocouple you have. Better yet, don't use connectors, get sensors with long leads on them.

If you do use connectors, you then need thermocouple extension wire to go with them. Normally this is the same metal (A and B) as the thermocouples. That way the thermocouple is made from A and B, the connectors are made from A and B and the wire is A and B. The only place you go to anything other than A and B is at the cold block.

Crazy stuff ....

Bob

**Squeeky** · 06-15-2012, 01:15 PM

I appreciate the discussion, but my thread has been hijacked

Rbeckett · 06-16-2012, 10:47 AM

Sorry Squeeky, unintended. Back on topic now.
Wheelchair Bob

**Squeeky** · 06-16-2012, 04:00 PM

No worries just giving you a hard time.

Rbeckett · 06-16-2012, 11:39 PM

Did you see the valve and stainless pipe set up that just came back up on the current threads. It is from 2010, but has a very similar setup to yours with some really really nice bent tubing and clean angle. I think the heading says something about Behemoth. Looks great and well thought out. Your auto panel would be perfect on a set up like that.
Bobn

**emjay** · 06-17-2012, 12:07 AM

Hey Squeeky!

I've talked to you before about the valves, as I'm going with a roughly 20-valve automated setup - includes hot or cold tap water, recirc/transfer for all three vessels, 3 pumps (I want to be able to brew back to back), a switch to send the BK transfer or recirc through a hopback/filter, and totally automated line drainage.

I've had two thoughts of how to control all this, but I really wanted to go with a Brewtroller as well. Problem is, I've been kind of worried I might not be able to properly implement it, and be forced to end up going with a simpler, electrical control setup anyways (similar to Kal's, but with actuated valves, probably controlled on a separate panel). Since our systems are going to be so similar (though mine will be 3 vessels), I'm wondering if I can pick your brain a bit if I run into any roadblocks. Is that okay? It won't be until later this year anyways.

Either way, I'll definitely be watching this thread!