eBIAB control circuit help

[fc36]

I'm looking for either a concise wiring diagram or just some advice on my control panel. So, naturally, I'm looking in Walker and/or P-J's direction. To give you some background, I'm a chemical engineer that designs control panels that utilize pids and all that good stuff for a living, but I'm not the best when it comes to designing a correct control circuit. I usually wing it and let our QC guys correct my wiring schemes.

Anyway, I'd like to be able to use a 3-way selector switch to either flip between my PID for mash control or a PWM circuit for boil control, but I'm at a loss for where to wire it into the circuit. Should it be on the +vdc or -vdc side from each control circuit to my element ssr and how do you send two different control signals to a ssr?

Also, if I'm doing that, do I use two contact blocks to break both sides of the low voltage circuit or one contact block on just the +12vdc side, for example? I also have an e-Stop to wire in and connect to an Undervoltage release on my gfci circuit breaker (all din rail mount btw). And where in the circuit would I place the gfci, ahead of the ssr to my element or after it?

Thanks in advance. I'm good at this stuff, but I just need a little help and advice to finalize the last few details of my circuit. I also have indicator lights and other pushbuttons to wire in for element indicators and what not.

 

[KPSquared]

I'm on my phone so I don't have a picture but if you go to my profile and find the thread I started called "wiring diagram crtique" I have how my switch is wired. Same sort of idea your looking for. Just start stacking control blocks. When the pid is on, the pwm is off and vice versa. I'm only selecting full power or pwm but you get the idea I hope.