cpeters - 7-12-2010 at 22:44
It this would be more appropriately placed in another section please feel free to move it.
I have a Corning hot plate. Stirring and heating, not digital. Very similar to the following:
http://catalog2.corning.com/Lifesciences/en-US/Shopping/Prod...
I have the need to control the temperature accurately to control reactions overnight. What I want is to be able to (either by a dial or digital) set
a certain temperature ~0-150C. This would be measured by a probe in a water or oil bath. And accuracy or about +/-5C.
I have a limited knowledge of circuits. I have taken one college course but it was pretty brief. I believe this would involve wiring a themocouple
and a relay.
Has anyone done this before or know a relatively simple way or achieving what I am looking to do?
Any help would be greatly appreciated. Thanks
Ephoton - 8-12-2010 at 04:05
solinoid and furnace controller (damb it I have forgoten the name of them could
some one help me out here)
hook temp prob into furnace controller and then have the solinoid that is also hooked
to the furnace controller too the mains power for your hotplate.
turn hotplate on full and let the furnace controller turn the hotplate on and off to keep
temp were it is ment to be.
better than soldering stuff and screwing up your hotplate.
ahh I found it a PID and thermocouple setup with solinoid is
what you want.
here is a PID on ebay to get you in the right direction.
there cheap too.
http://cgi.ebay.com.au/PID-SSR-TEMPERATURE-CONTROLLER-FURNAC...
[Edited on 8-12-2010 by Ephoton]
[Edited on 8-12-2010 by Ephoton]
cpeters - 8-12-2010 at 08:39
I haven't ever opened up one of these hot plates before to see what the wiring looks like. Do you think it would be fairly straight forward?
Also, would I be able to keep the stirrer ON and only have the heater turn ON/OFF when the temperature gets above a set level?
Ephoton - 8-12-2010 at 12:16
that makes it a bit harder 
most of the hotplates I have seen run of an IC.
[Edited on 8-12-2010 by Ephoton]
Magpie - 8-12-2010 at 13:44
See:
http://www.sciencemadness.org/talk/viewthread.php?tid=14682#...
The power to the stirrer function would have to be provided by an independent source. This would involve some wire reroute in the hotplate. I have
not done that as I find that I get sufficient stirring even though it is intermittent.
[Edited on 8-12-2010 by Magpie]
[Edited on 8-12-2010 by Magpie]