Double-R
Well-Known Member
Been looking an waiting, Pretty sure i'm not the only one wondering,
how do you build/make one. Some say get a PWM , you dont need a PID setup . SO I ask . HOW..
Buy this: http://www.bakatronics.com/shop/item.aspx?itemid=383
Replace C1 with a 2.2uF capacitor to lower the frequency.
Use a 12V wall wart as a power supply to the PWM board.
Connect the output of the PWM board to a SSR to control your boil.
This is how I did it and I'm very happy. Cheap, easy, responsive control.
The PWM controller turns the relay on and off faster for more heat, and slower for less. Think of it as controlling PULSES of electricity to the element. The faster the pulses come, the hotter the element will get.
Yeah, now that I re-read my post I have no idea why I posted it like that. I guess that's what happens when you are trying to install Exchange Server and figure Mash Adjustments while reading and posting on HBT...
The image above has a very good sample of the frequency showing the hotter vs the cooler pulse widths. It's more about the time per pulse that the element is on vs the time per pulse that it's off.
Here's a diagram I made. I tried to keep it simple. Hopefully it's enough to get you going. It's easier to understand once you get your hands on this stuff and start piecing it together.
freddyb said:Here's a diagram I made. I tried to keep it simple. Hopefully it's enough to get you going. It's easier to understand once you get your hands on this stuff and start piecing it together.
http://imageshack.us/photo/my-images/804/pwmboil.jpg/
Be careful here. I know some might argue the HBT board goes a bit overboard when it comes to safety, but is that really possible when we're using water, metal tanks and 30-50 amps at 115 to 230 V?
Specifically, the following concerns on the discussed schematic.
- There is no ground shown. ALWAYS use ground; no exceptions -- this absolutely should be shown on any schematic we post.
- Once the DPDT is switched ON, you'll have 120V at the element. This combined with no ground to the tanks could make for a very bad brewing day.
vballdrummer said:Be careful here. I know some might argue the HBT board goes a bit overboard when it comes to safety, but is that really possible when we're using water, metal tanks and 30-50 amps at 115 to 230 V?
Specifically, the following concerns on the discussed schematic.
[*]There is no ground shown. ALWAYS use ground; no exceptions -- this absolutely should be shown on any schematic we post.
[*]Once the DPDT is switched ON, you'll have 120V at the element. This combined with no ground to the tanks could make for a very bad brewing day.
What about the switch? is 30A required there, or is 20A enough?
For those of you who have used the bakatronics controller as suggested by freddyb, do you know what the duty cycle is for the base kit? Freddyb suggested switching out one of the capacitors, how does that affect the duty cycle and why is it necessary? Thanks for the input.
Cheers,
Greg
I guess I should have been more clear. It appeared in the wiring diagram that one leg of the 240 amp service was feeding the wall wart. Was this wired up to an outlet that is plugged in or directly to a transformer? I was hoping to attach my toolbox to the 240 and do all the wiring inside, so I was curious if there was a preferable/safer option.
Buy this: http://www.bakatronics.com/shop/item.aspx?itemid=383
Replace C1 with a 2.2uF capacitor to lower the frequency.
Use a 12V wall wart as a power supply to the PWM board.
Connect the output of the PWM board to a SSR to control your boil.
This is how I did it and I'm very happy. Cheap, easy, responsive control.
Bump for an answer. Anyone with this kit and a 'scope that could figure out the pule frequency for us? I would like to know the same thing.
P.S.
the duty cycle is not what is changed by the cap, the pot changes the duty cycle which is what we use to regulate heat output. the frequency of the pulse is what is in question.
were can i find the 2.2uf capactior at? thanks
edit: will this work( http://www.radioshack.com/product/i...Name=Type&filterValue=Electrolytic+capacitors )
Can you post the model/part number of the transistor? I want to try to build one in a super small package, like inside a 2" long piece of 1/2"-3/4 PVC, and put the pot in the end, mount behind panel door for my Hand-Off-Auto switches to have Variable-Off-Auto
Here. C1061.
Here is one I have working with a grand total of 3 components:
555
2.2uf cap
500k pot
It has about a 1Hz rate
I have it working now for 2 hours, and am letting it run overnight to test stability, but the package does not get any smaller than this...
CircuitBee drawing
anyone have a quick way I can get the imbedded code below to have the drawing show up here?
<iframe width='500' height='350' frameborder='0' src='http://c.circuitbee.com/build/r/schematic-embed.html?id=0000000094'></iframe>
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