PID with controllable output effect?

[wess]

Hello guys,

Im searching for a PID for my future "Braumeister clone" that I can limit the maximum output effect on.

The reason is that I want to be sure that I wont burn the mash when Im mashing, so when Im mashin I want to limit the max output to about 50% or something like that and still use PID-mode (I know Manual Mode on some PIDs let you control the output), but when Im boiling I want it to be 100%.

 

[Brettomomyces]

http://www.auberins.com/index.php?main_page=product_info&products_id=444

Like this guy? It's not exactly like a manual PID but can control the power in a kind of linear way.

 

[Bobby_M]

Two options I'm aware of.
1. Use a regular PID for temp control signalling one SSR and use the power control linked above to a second SSR. Have a hot leg of the element go through both SSRs in series. The PID still calls for heat in relatively large cycles, like one second pulses or longer. Then you have the power controller potentially limiting the power down to the 1/60th of a second level so that if you set the power controller to 50%, the PID literally cannot make the element run more than half power even for a second.

2. Use a 240v to 120v selector switch so you can go from full power to quarter power. This is a little cheaper, but not as adjustable.

 

[wessman]

Ok, cool. Thanks a lot for your answers! I think the volt switch may be enough for me =)

 

[Bobby_M]

Keep in mind you'll drop about $30 for a 30amp capable DPDT switch which is about the same price as the power controller with infinite adjustability.