Brent i love the look of those devices. Cant wait to get my hands on some but have a few other projects in the works first.
Now given this thread shows people about the PID and use of SCR to manage the temp of their smoker i thought i would post some info here related to your update regarding the timing of the units output.
The thing about all these kinds of things and theory is that until one has personally experienced certain things happening some dont believe them possible.
So i want to add a few things here about some of my practices that make things safer in the long run.
I dont like crimp to wire lugs, i dont believe the resulting contact is a good one especially if the connection carries high current or is critical to the safe operation of a device. So what i do is solder the lugs on yeah its a pain but i know the joint is sure.
Second never screw down on a bare wire in a terminal. I have no idea how this has survived in code all these years in the electrical world. I was taught to put a ferrule over wire and then insert that into a screw type clamp terminal so that 1) all the wire is in the ferrule ensuring you using the full cross sectional area of the specified wire for the connection such that it comfortably carries the load. 2) now the screw terminal is clamping down on the ferrule and not the wire which if there is no tab beneath the screw it normally cuts into the wire and relies in essence on the tightness of the entry way to hold all the wire for clamping.
For this kind of connection to be safe the screw has to be properly snugged down and the wire should not be open to being moved. ie good practice is a tie bar. But that is not done in electrical panels.
My memory "blisters on my hand" that make me do this the long hard way are witnessing a glowing circuit breaker in real life when the connection to a high current device was not tight enough to prevent the joint from becoming a resistor and heating up.
Then when the opportunity to do so arises i always put a ring lug on so the connection cannot fall out the way a fork lug can. Again a bit more fiddle work.
Now with a soldered lug and ring lug all that needs to happen to have a safe joint is to make sure you tightened down on the lug ring with the screw.
This is what caused me to change out the screw terminal on my DP motor the other day which i poste
d a thread on in safety section here .
I know i am sounding like an old granny but hey rather that than have a fire.
This video brings this whole issue to mind.
http://www.youtube.com/watch?v=yM_5tGAZD64
I am all for modern gadgets and techie stuff but if applied the way things look in you tube videos without full attention to other details then oops things will happen.
So to validate what Brent said about not feeling comfortable with the PID output proportion on this setup watch the video and it gives you an idea of what happens to an SCR when it goes through these cycles.
Where i have issue with the guy doing the video is the lack of attention to how to secure the terminals to the SCR. These devices are design to switch fast that's their differentiating advantage over physical contacts. What needs to be attended to is whether the connections are done properly to handle the load and not create a resistive joint.
If a lug is used and properly seated then it will act like a washer and be securely clamped provided you not using a Tai Chi terminal block like was in my DP motor.
Many people will think well i dont have a lug so i will solder the end of my wires and put them in that way and this will ensure i get all the wire under the screw.
WRONG. For those that want to dabble and dont know solder will flow under pressure and you will get a loose joint and you will have a safety issue. How bad will just depend on what you connecting up.
Again my ancestors in the desire to make things cheap and easy our three pin plug system used a round piece of brass as a connector going into a round hole on the wall receptacle. Nice 1/4 inch chunk of brass not a super cheap metal. Then what they did was to drill a hole sideways through said brass rod and another on the top side which was drilled and tapped. A small brass screw was then used to come in from the top and clamp down on wire pushed through the side hole. The screw would notoriously cut the stranded wire on appliances and the hole on the side would be so small that getting stranded wire to go through as a total bunch meant twisting it up or what some appliance manufacturers did that thought they were making it easy for people to put a plug on was to dip the ends in solder. Go figure they just added to the problem.
So yeah i guess i am probably a pain in the but with these comments because when i build something like this i make up discrete individual wires with both ends terminated in lugs that can attach to each end. In the case of the parts used in the BBQ Smoker Brent has shared, all the devices needed have screw terminals. So its pretty easy to do this.
By lugs i mean these things just in case my terminology dont match yours.
Project just went from simple quick fix to rethink. Glad i aint cut the holes yet. 
