Hi all,

I'm going to swap the controller on my reflow oven with something =20
custom.  It has 3 zones, conveyer, convection and cooling fans.  I =20
want to do this as simple/quick as possible, but would like to keep =20
the front panel interface (40x8 LCD, various touch switches, E-stop =20
and power switch).  There are 3 heating elements each with it's own =20
solid state relay (3-32V control voltage).  And 3 thermocouples.

So I'll have to create my own controller to interface with the front =20
panel elements and fans/conveyer, but would prefer to find some =20
off-the-shelf PID temperature controllers, to save me the hassle of =20
create PID controllers with autotuning.  And it would have to have =20
some interface that I can control it with my controller.

I found some decent candidates at Omega, Factorymation, Automation =20
Direct, etc, with 3 units running in the ballpark of $220-$270 total.  =20
I can live with that, but lower cost would be nicer.  These also come =20
with things I don't need -- UI (LED displays, switches, etc), ability =20
to do ramps/profiles/etc (I just set to a specific temperature and =20
regulate).  And they all have RS485/Modbus as the interface, and I'd =20
have to go figure out that part and code it.  But they have =20
autotuning, which I really want.

So instead, I'm thinking I should be able to find some open-source PIC =20
(or other uC) PID temperature controller project that I can use for =20
this.  Building the circuit/PCB/etc is no problem.  Or perhaps =20
something lower-cost commercial (open-frame for lower cost).  I know =20
that there is a PID library for the Arduino, but I haven't seen any =20
autotuning mechanism for it yet, and I think it will take some effort =20
for me to figure out how to create and autotuning algorithm.

Thoughts welcome.  Know of some COTS open-frame type temperature =20
regulator?  Or a PID temp-control project?  Or perhaps a Modbus master =20
library for PIC?  Or...?

Cheers,
-Neil


--=20
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.