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I have a commercial reflow controller I was hoping to programme for annealing/normalising plexiglass but its not up to it.
I have therefore purchased a reflow controller shield.
I notice some here have done similar.
Requirement is for a controlled ramp up to 80 or 140 deg C over about 3 hours , 2 hours soak, controlled temp reduction over about 20 hours.
Anyone got any thoughts on this programming wise ? 
I intend to zero voltage switch discrete half cycles so range will be in 1% steps .
 Finer steps could be had by doing 1 cycle in 99,98 etc.
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Maybe not the most DIY solution, but this device: http://www.auberins.com/index.php?main_page=product_info&cPath=1&products_id=4 sounds like it will do just what you're looking for.  Add a temp sensor and an SSR to control the heating, and you should be good to go.
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Thanks, I have looked at these before,I cannot see a way of doing the cool down period though.
I was wondering if someone who knows the pid library had any ideas.

They either do ramp up or ramp down but not both,also I think that 30 points is not enough.
Temp accuracy is not critical but rate is, cool down is the critical one.

I've characterised the oven so hope to be able to generate a rough linear equation to approximate then use pid to tweak ?
« Last Edit: April 04, 2013, 10:44:52 am by Boardburner2 » Logged

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The PID algorithm can handle the cool down fine.  Is your oven capable of the proper cooling rate?
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Yes, some heating during the cool down period will be needed to slow down the cooling process.
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