as stated before, i did not read the manual. so i don't know for sure how this device works. i am not sure if relay contacts only operate when certain mode is chosen or any time when temperature is above/below some setpoint. this is offered for consideration by those that did get familiar with the product.

 

I tested your 2 relay circuit works just fine. Much thanks. Just not %100 sure if I can connect the rc snubber module on the common (C) and the NC (D) as per diagram.

 

RC snubber can be added across inductive load or across contacts.

 

So here it is. Unfortunately half finished. I was just about to install the temperature controllers and the 240 VAC outlet to the panel and realized I got a little problem. It has been a while since I have posted so a basic recap is warranted.

Although the actual setup is patterned after panic mode’s clever circuit I am going to disregard some components just to keep things simple. The setup comprises of the following:

6 (STC-1000) temperature controllers running on 12 VDC which are wired to a normally open contactor rated at 240 VAC (12 VDC coil). The contactor is wired to a 240 VAC outlet, to which plugged in are an ozone and an oxygen generator which in turn feed a column reactor.

The column reactor is monitored by six probes hooked up to the 6 STC 1000’s, if and when one of the probes hits the trigger temperature of 40 degrees Celsius the circuit is disrupted - the contactor reverts to a normally open state with no power running through the 240 VAC outlet, which automatically shuts down the generators.

The problem with this current setup is that when the station is left unattended and a trigger temperature is hit the system shuts down the generators (which is awesome), but as soon at the temperature in the reactor drops a couple degrees, the temperature contollers re-energies the contactor’s coil, power comes back on and the cycle repeats, continuously turning the generators on and off. No good.

When the target temperature is triggered the power should turn off and remain off until it is switched back on manually - as in resetting a circuit breaker. To my knowledge the only way around this would be 240 VAC GFCI with a manual reset. Unfortunately I could not find one online.

Much dismayed. I could really use a good idea right now.

 

Much dismayed. I could really use a good idea right now.

Suggestion #1
The CPC1002 is a solid state relay (SSR) that when activated applies 12 volts to the Contactor coil.
When all the STC switches are first closed the SSR is momentarily turned ON through D1,C1 and R2.
D2 and R1 immediately provide a latching action to hold the SSR ON. At this time C1 is fully charged.
When any STC contact opens the SSR drops out shutting OFF the Contactor.
C1 stays charged and cannot discharge because of D1.
Next time when all the STC contacts are closed again the SSR does not turn ON because C1 is fully charged.
The SSR will remain OFF regardless of how many times any STC contact opens or closes until Reset.

 

Wow! Thank you. With no electronics background or whatsoever I got to say this circuit is daunting but I will definitely take all the time necessary to understand it and its integration. If I have any questions I will post.


Than you, sghioto!

 

Would you prefer using a Module with a few extra components added?
What's the maximum time the system is left unattened?

 

The reactor is located in a remote area just in case something goes boom. Sometimes it could be as long as a week before I head out there. So I’d say the system can be left unattended for as much as 7 days. With the “Module” schematic you have made it clear as glass for me. I understand. Much thanks!! It makes the CPC1002 diagram also easier to understand via cross referencing - although not there yet.

For the “Module” schematic by, “ To Contactor Coil” you mean A2 or A1?

The temperature control system also comprises of an additional contactor (normally closed) which gets energized by the STC 1000’s when cooling kicks in. It was proposed by panic mode as a redundant (safety contactor) just in case the contacts of the first contactor (normally open) got stuck. So I guess I would use another module for the normally closed contactor with the same wiring?

 

Can't see in the photo the coil connections.
Link to the contactor?

 

I will prepare a diagram and post soon just to make sure we are on the same page

 

Here is a schematic of the current temperature control system - without fusing. Hope this helps.

 

So I guess I would use another module for the normally closed contactor with the same wiring?

I believe so.

 

So from what I understood one module will be connected to line A1 (Heating) and the other module also to line A1 (Cooling), with each module basically acting as a relay before a relay. Hopefully the capacitor will hold it’s charge for more than a week. Anyway I just ordered the parts. I will figure it out - one way or the other. If I have any questions I will post. Much thanks sghioto! This forum has some beautiful minds!

 

Hopefully the capacitor will hold it’s charge for more than a week

What type capacitor did you order?

 

Hope it is the right one.

 

Not the one's I would recommend.
Like the photo, a polypropylene type rated 100 volts is better.

 

Gotcha. Thanks!

 

I have that circuit on a breadboard.
Will give updates.

 

Nice!