Controlled environment? Prob not. It's in a garage which can be =20 quite hot or cold depending on time of year. This is not the typical =20 toaster-oven reflow, but a proper conveyor oven, so don't really want =20 to implement something that may cause me a lot of problems and I'd =20 have to re-do again. With the original controller, it took me a while =20 with lots of tweaks of a few degrees here and there to get it right, =20 so a few degrees do matter. Cheers, -Neil. Quoting Marc Nicholas : > Hi Neil, > > I did something similar for my sous-vide cooker project. > > But I ended up using fuzzy logic rather than PID, so my question is: =20 > do you really need PID? Also, given you have a fairly controlled =20 > environment, maybe you can tweak the fuzzy logic rather than build =20 > auto-tune? > > -Marc > > On 2011-09-01, at 11:03 AM, PICdude wrote: > >> Hi all, >> >> I'm going to swap the controller on my reflow oven with something >> custom. It has 3 zones, conveyer, convection and cooling fans. I >> want to do this as simple/quick as possible, but would like to keep >> the front panel interface (40x8 LCD, various touch switches, E-stop >> and power switch). There are 3 heating elements each with it's own >> solid state relay (3-32V control voltage). And 3 thermocouples. >> >> So I'll have to create my own controller to interface with the front >> panel elements and fans/conveyer, but would prefer to find some >> off-the-shelf PID temperature controllers, to save me the hassle of >> create PID controllers with autotuning. And it would have to have >> some interface that I can control it with my controller. >> >> I found some decent candidates at Omega, Factorymation, Automation >> Direct, etc, with 3 units running in the ballpark of $220-$270 total. >> I can live with that, but lower cost would be nicer. These also come >> with things I don't need -- UI (LED displays, switches, etc), ability >> to do ramps/profiles/etc (I just set to a specific temperature and >> regulate). And they all have RS485/Modbus as the interface, and I'd >> have to go figure out that part and code it. But they have >> autotuning, which I really want. >> >> So instead, I'm thinking I should be able to find some open-source PIC >> (or other uC) PID temperature controller project that I can use for >> this. Building the circuit/PCB/etc is no problem. Or perhaps >> something lower-cost commercial (open-frame for lower cost). I know >> that there is a PID library for the Arduino, but I haven't seen any >> autotuning mechanism for it yet, and I think it will take some effort >> for me to figure out how to create and autotuning algorithm. >> >> Thoughts welcome. Know of some COTS open-frame type temperature >> regulator? Or a PID temp-control project? Or perhaps a Modbus master >> library for PIC? Or...? >> >> Cheers, >> -Neil >> >> >> -- >> http://www.piclist.com PIC/SX FAQ & list archive >> View/change your membership options at >> http://mailman.mit.edu/mailman/listinfo/piclist > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .