The instructions seem straight forward although he is using a slightly different PID.
Here is what works: PID powers on, PT100 reads correct temperature, multimeter is reading around 120vac at the heaters, the water pump works and the relay clicks on when the output lights up
What doesnt work: The heaters are not heating up.
I made a terrible wiring diagram to help decipher any errors
any help would be appreciated. Im an uber rookie to wiring and using a multimeter as well
Last edited by bleach8484 on Tue Jan 18, 2011 8:36 pm, edited 1 time in total.
If you have 120V across the heaters and they are not getting hot, then there is something wrong with the ehaters -- is there an over temp thermnostat in them that needs to be reset? Maybe a loose connection? Think of them as light bulbs -- when you put the AC line voltage across a light bulb, it lights unless no current is flowing because the connection is open, as when the bulb is burned out or when the switch is set to off. When you put AC line voltage across a heater, it gets hot, unless no current is flowing, meaning the element is open or the connection is open somewhere. Couldn't read you diagram -- too small, and when I enlarged it, it got too fuzzy...
What kind of relay do you have there? You say that the relay clicks, which tells me it's a mechanical relay. From your diagram, it looks like you're connected up to the SSR relay output (pins 6 and 7).
The article you linked to uses the CD101 which has built-in support for driving the primary coils of a mechanical relay. The JLD612 does not. The SSR output may be enough to make the relay click, but I think it's not designed to provide enough current to properly energize the coils of a mechanical relay.
So, what are the specs on that relay you are using?
JLD612 provide two relay output. You can use it to control any devices. Remeber, it's output is On/Off switch (relay output), not voltage output. Output from the SSR is 8V DC with low current, possible 20mA at most which is not high enough to drive a big relay. To drive a coil appliance, it's better to use the JLD612 relay instead of the SSR.
" It’s best to use a relay, since usually the relays built into these controllers are only rated for switching about 375W, and your heaters add to 900W."
That was a response from the creator of this project. It seems people destroyed the pid when using the internal relay.
Correct. A lot of forums use the internal relay for controlling high power equipment and end up burn out the relay. It's suppose to use it to drive samll device, something rate about 1A or 1.5A at most, even though the relay rated 3A. But I won't bet on that. So, it means that the controller relay should be used to drive anything over 150Watt for safety and for good sake.
Are you using the Radio Shack Relay used in the Food Geek article? I took a look and have following conclusion: Don't use it. Here's why.
The 275-005 specs don't state what the resistance is of the coil, and as such we don't know what kind of current it needs to clamp shut. The JLD612 SSR output specs state that it's 8v, but that's open circuit, not loaded. I checked the voltage of mine with the SSR connected and it happens to be 6.4V. If we were comparing apples to apples, that would not be enough for your relay. Did you see the reviews of the 275-005 on the Radio Shack website? The reviewers say that even 9V isn't enough to clamp it.
Despite what the specs say, the 275-005 really looks too small for the application. If you're using the same heating coil setup shown, then you've got 3 X 300W @120V, or 7.5 amps. It says' it's rated for 12A, but I find that hard to swallow - just look at the tiny leads! It's meant for a circuit board, not really for power applications. One reviewer reportedly melted his with just 4 amps.
Input/Output capacities aside, there is also a longevity factor. When the PID is doing it's thing, it pulses the output on and off - lots. Would those mini relay contacts last with 7.5A being switched on and off thousands of times each time you cook something? And what about the noise? Do you really want to hear that clickity-clack going when you make your 72-hour short ribs?
You could find a better mechanical relay for the job, such as one with a 120V coil, and then switch power to it using J2 pins 4/5 and program it to use outY=1 control mode. My recommendation however is to go with a SSR - it's designed for the job, quiet, long lasting (no moving parts) and easier to wire up.
Use an SSR. Period. Get one rated for 40 amps or more. Use a heat sink, Will last more or less forever, no noise, just works. Small size is no good thing here.
I went and picked up an ssr relay. Now it's time to rebuild.
It's a 4 prong relay.
Now to rewire this I would run the two inputs to pins 6 and 7. The power to pin one. And connect the heating elements to #2 load side on the relay?
Connect the JLD612 pins 6/7 to the relay's 3/4, respectively. Route power to your heater through relay pins 1/2 (or 2/1 - polarity does not matter on the output of the relay, and it' A/C anyway...).
