Arduino code not giving target temperature.

Hi,

Please check the wiring diagram you have posted, you have gnd connected to the +ve input term of the Crydom, and the -ve input term to the Vref. The -ve input should go to gnd and the +ve input to the output pin of your Arduino that controls the Crydom.

Tom... :)

boardburner2 It is said that a picture is worth a thousand words. Well, that is true for a noob like me, but I agree that depends on the audience. I was just trying to be comprehensive, but I understand your disinterest & boredom at the karma64 level. One more attachment & I promise it's the last.

Last attachment.

Hi,
Have you got the oven connected by switching to the mains cable that comes out of the oven?
If so it means all the thermostat gear in the oven is still in circuit.
Have you tried the oven with the oven thermostat in 240C rather than TOAST?
dial_1.jpg
Tom… :slight_smile:

The reason im going on about this is some of these devices are not a proper thermostat. They actually a crude thermally controlled form of pwm.

Hi,

Boardburner2: The reason im going on about this is some of these devices are not a proper thermostat. They actually a crude thermally controlled form of pwm.

Yes, tempostats I think they are called, used on electric stove heat rings. Tom.... :)

I built my oven after i was given it by a relative as she could not cook with it, she bought another of the same model. Similar problem and i tested them. They regulated, but the temperature bore little relevance to the actual dial setting. Wildly different between the two ovens as well although one of them was in my shed which was much colder.

Mine would not get to advertised temp either it was 30 deg less i think, could only do lead solder initially. I think that was a fault though rather than improper operation.

dalpets: boardburner2 It is said that a picture is worth a thousand words. Well, that is true for a noob like me, but I agree that depends on the audience. I was just trying to be comprehensive, but I understand your disinterest & boredom at the karma64 level. One more attachment & I promise it's the last.

You have missed the point.

A couple of questions have been asked which you have not answered.

One other point, siting the thermocouple is important. It needs to be attatched to the board, left dangling it will give the symptoms you have described.

Boardburner2: One other point, siting the thermocouple is important. It needs to be attatched to the board, left dangling it will give the symptoms you have described.

I'm not using any boards until I resolve the temp issue?

dalpets: I'm not using any boards until I resolve the temp issue?

Then stick it on a piece of scrap board in the middle of the oven.

And re read toms post #3. If there is something you do not understand, ask.

Boardburner2: You have missed the point.

A couple of questions have been asked which you have not answered.

Give me a break mate!. I've spent most of my waking hours on this, admittedly too much time on the sketch & attachments.

I haven't forgotten the questions.

dalpets: The oven front panel temp dial has 3 settings viz., 240C, Grill & Toast. Only the Toast setting was able to take me through the sketch code without a problem. I have only verified that success on 3 runs-I'm keeping my fingers crossed.

So your circuit is working, something else is the problem unless you changed something.

dalpets: Give me a break mate!.

Sorry not trying to put pressure. Just pointing out a problem which is actually very common with newcomers here.

Hi Tom,

TomGeorge:
Hi,
Have you got the oven connected by switching to the mains cable that comes out of the oven?
If so it means all the thermostat gear in the oven is still in circuit.
Have you tried the oven with the oven thermostat in 240C rather than TOAST?
dial_1.jpg
Tom… :slight_smile:

1st question re mains cable =yes (connections as per my sketch). How do I take the oven thermostat out of circuit. Is an internal modification of the oven required. Details please for a noob.

2nd question-have used all 3 knob positions-all fail the target 9 out of 10 times.

TomGeorge: Hi, Is the controller shutting OFF the element at 206C or is it still turned ON.

This is the question i was referring to.

What are the lights doing when you reach target temperature. The reason for this question is to determine if its your controller or the oven at fault.

You may not need to modify your oven if the problem lies elsewhere.

Something I just noticed - the solid-state relay is rated for 5A, it appears, but the toaster oven is 1400W so will draw over 5A. Does the SSR have over-current protection? I'm wondering if it's shutting itself down and stopping your setup reaching the set temperature. You might need to get one with a higher current rating.

Or does the toaster oven have a couple of elements that total 1400W, but you're only using one element?

Just a thought.

TomGeorge: Hi, Is the controller shutting OFF the element at 206C or is it still turned ON. Can you post picture of your project so we can see the arrangement and size of the oven.? Is the oven and heater element designed to go to 240C, what power wattage is the element.

Yes the element does shuts off in sync with the controller. The oven has 4 elements: 2 upper & 2 lower. With an independent thermometer I've had it to 275C

TomGeorge: Do you have the supply input to the 595 AMPLIFIER bypassed and the output from the AMPLIFIER bypassed?

I don't understand the question, Tom. Could you please clarify in circuit wiring terms for a noob.

dalpets: The oven has 4 elements: 2 upper & 2 lower. With an independent thermometer I've had it to 275C

On mine in the toast position only the upper 2 elements are on.

A 5A ssr is fine with that.

If i use it in the oven position it does indeed shut down as xxx oldsteve has suggested.

Provided that the power light and arduino light are blinking in sync its not shutting down. If arduino blinks and power light does not then it is.

Another thought has occoured.

Say you have blink 1 second on to 1 second off. Eventually a point is reached (equilibrium) beyond which temp cannot increase.

To cure that the mark to space ratio of the blink needs to be changed.

Ie more on less off.

If at 206 the light continues to blink i suspect this or a faulty thermostat.

If the light stops blinking then that would imply measurement problem.

OldSteve: Something I just noticed - the solid-state relay is rated for 5A, it appears, but the toaster oven is 1400W so will draw over 5A. Does the SSR have over-current protection? I'm wondering if it's shutting itself down and stopping your setup reaching the set temperature. You might need to get one with a higher current rating.

Or does the toaster oven have a couple of elements that total 1400W, but you're only using one element?

Just a thought.

Hi OldSteve,

Thanks for your thoughts. Looked the specs up online @ http://www.digikey.com.au/product-detail/en/crydom-co/EZ240D5/CC2176-ND/752093 Unfortunately there is no mention of the current rating. I haven't taken notice which elements come on at each setting but I will do so. Thanks